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git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux
Pull gpio updates from Bartosz Golaszewski:
"Relatively few updates for this release cycle. We have a single new
driver and some minor changes in drivers, more work on limiting the
usage of of_node in drivers and DT updates:
- new driver: gpio-en7523
- dt-bindings: convertion of faraday,ftgpio010 to YAML, new
compatible string in gpio-vf610 and a bugfix in an example
- gpiolib core: several improvements and some code shrink
- documentation: convert all public docs into kerneldoc format
- set IRQ bus token in gpio-crystalcove (addresses a debugfs issue)
- add a missing return value check for kstrdup() in gpio-merrifield
- allow gpio-tps68470 to be built as module
- more work on limiting usage of of_node in GPIO drivers
- several sysfs interface improvements
- use SDPX in gpio-ts4900"
* tag 'gpio-updates-for-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux:
gpio: ts4900: Use SPDX header
gpiolib: Use list_first_entry()/list_last_entry()
gpiolib: sysfs: Simplify edge handling in the code
gpiolib: sysfs: Move kstrtox() calls outside of the mutex lock
gpiolib: sysfs: Move sysfs_emit() calls outside of the mutex lock
gpiolib: make struct comments into real kernel docs
dt-bindings: gpio: convert faraday,ftgpio01 to yaml
dt-bindings: gpio: gpio-vf610: Add imx93 compatible string
gpiolib: Simplify error path in gpiod_get_index() when requesting GPIO
gpiolib: Use short form of ternary operator in gpiod_get_index()
gpiolib: Introduce for_each_gpio_desc_with_flag() macro
gpio: Add support for Airoha EN7523 GPIO controller
dt-bindings: arm: airoha: Add binding for Airoha GPIO controller
dt-bindings: gpio: fix gpio-hog example
gpio: tps68470: Allow building as module
gpio: tegra: Get rid of duplicate of_node assignment
gpio: altera-a10sr: Switch to use fwnode instead of of_node
gpio: merrifield: check the return value of devm_kstrdup()
gpio: crystalcove: Set IRQ domain bus token to DOMAIN_BUS_WIRED
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git://git.kernel.org/pub/scm/linux/kernel/git/hid/hid
Pull HID updates from Jiri Kosina:
- rework of generic input handling which ultimately makes the
processing of tablet events more generic and reliable (Benjamin
Tissoires)
- fixes for handling unnumbered reports fully correctly in i2c-hid
(Angela Czubak, Dmitry Torokhov)
- untangling of intermingled code for sending and handling output
reports in i2c-hid (Dmitry Torokhov)
- Apple magic keyboard support improvements for newer models (José
Expósito)
- Apple T2 Macs support improvements (Aun-Ali Zaidi, Paul Pawlowski)
- driver for Razer Blackwidow keyboards (Jelle van der Waa)
- driver for SiGma Micro keyboards (Desmond Lim)
- integration of first part of DIGImend patches in order to ultimately
vastly improve Linux support of tablets (Nikolai Kondrashov, José
Expósito)
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/hid/hid: (55 commits)
HID: intel-ish-hid: Use dma_alloc_coherent for firmware update
Input: docs: add more details on the use of BTN_TOOL
HID: input: accommodate priorities for slotted devices
HID: input: remove the need for HID_QUIRK_INVERT
HID: input: enforce Invert usage to be processed before InRange
HID: core: for input reports, process the usages by priority list
HID: compute an ordered list of input fields to process
HID: input: move up out-of-range processing of input values
HID: input: rework spaghetti code with switch statements
HID: input: tag touchscreens as such if the physical is not there
HID: core: split data fetching from processing in hid_input_field()
HID: core: de-duplicate some code in hid_input_field()
HID: core: statically allocate read buffers
HID: uclogic: Support multiple frame input devices
HID: uclogic: Define report IDs before their descriptors
HID: uclogic: Put version first in rdesc namespace
HID: uclogic: Use "frame" instead of "buttonpad"
HID: uclogic: Use different constants for frame report IDs
HID: uclogic: Specify total report size to buttonpad macro
HID: uclogic: Switch to matching subreport bytes
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git://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86
Pull x86 platform driver updates from Hans de Goede:
"New drivers:
- AMD Host System Management Port (HSMP)
- Intel Software Defined Silicon
Removed drivers (functionality folded into other drivers):
- intel_cht_int33fe_microb
- surface3_button
amd-pmc:
- s2idle bug-fixes
- Support for AMD Spill to DRAM STB feature
hp-wmi:
- Fix SW_TABLET_MODE detection method (and other fixes)
- Support omen thermal profile policy v1
serial-multi-instantiate:
- Add SPI device support
- Add support for CS35L41 amplifiers used in new laptops
think-lmi:
- syfs-class-firmware-attributes Certificate authentication support
thinkpad_acpi:
- Fixes + quirks
- Add platform_profile support on AMD based ThinkPads
x86-android-tablets:
- Improve Asus ME176C / TF103C support
- Support Nextbook Ares 8, Lenovo Tab 2 830 and 1050 tablets
Lots of various other small fixes and hardware-id additions"
* tag 'platform-drivers-x86-v5.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86: (60 commits)
platform/x86: think-lmi: Certificate authentication support
Documentation: syfs-class-firmware-attributes: Lenovo Certificate support
platform/x86: amd-pmc: Only report STB errors when STB enabled
platform/x86: amd-pmc: Drop CPU QoS workaround
platform/x86: amd-pmc: Output error codes in messages
platform/x86: amd-pmc: Move to later in the suspend process
ACPI / x86: Add support for LPS0 callback handler
platform/x86: thinkpad_acpi: consistently check fan_get_status return.
platform/x86: hp-wmi: support omen thermal profile policy v1
platform/x86: hp-wmi: Changing bios_args.data to be dynamically allocated
platform/x86: hp-wmi: Fix 0x05 error code reported by several WMI calls
platform/x86: hp-wmi: Fix SW_TABLET_MODE detection method
platform/x86: hp-wmi: Fix hp_wmi_read_int() reporting error (0x05)
platform/x86: amd-pmc: Validate entry into the deepest state on resume
platform/x86: thinkpad_acpi: Don't use test_bit on an integer
platform/x86: thinkpad_acpi: Fix compiler warning about uninitialized err variable
platform/x86: thinkpad_acpi: clean up dytc profile convert
platform/x86: x86-android-tablets: Depend on EFI and SPI
platform/x86: amd-pmc: uninitialized variable in amd_pmc_s2d_init()
platform/x86: intel-uncore-freq: fix uncore_freq_common_init() error codes
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git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild update for C11 language base from Masahiro Yamada:
"Kbuild -std=gnu11 updates for v5.18
Linus pointed out the benefits of C99 some years ago, especially
variable declarations in loops [1]. At that time, we were not ready
for the migration due to old compilers.
Recently, Jakob Koschel reported a bug in list_for_each_entry(), which
leaks the invalid pointer out of the loop [2]. In the discussion, we
agreed that the time had come. Now that GCC 5.1 is the minimum
compiler version, there is nothing to prevent us from going to
-std=gnu99, or even straight to -std=gnu11.
Discussions for a better list iterator implementation are ongoing, but
this patch set must land first"
[1] https://lore.kernel.org/all/CAHk-=wgr12JkKmRd21qh-se-_Gs69kbPgR9x4C+Es-yJV2GLkA@mail.gmail.com/
[2] https://lore.kernel.org/lkml/86C4CE7D-6D93-456B-AA82-F8ADEACA40B7@gmail.com/
* tag 'kbuild-gnu11-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
Kbuild: use -std=gnu11 for KBUILD_USERCFLAGS
Kbuild: move to -std=gnu11
Kbuild: use -Wdeclaration-after-statement
Kbuild: add -Wno-shift-negative-value where -Wextra is used
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Merge yet more updates from Andrew Morton:
"This is the material which was staged after willystuff in linux-next.
Subsystems affected by this patch series: mm (debug, selftests,
pagecache, thp, rmap, migration, kasan, hugetlb, pagemap, madvise),
and selftests"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (113 commits)
selftests: kselftest framework: provide "finished" helper
mm: madvise: MADV_DONTNEED_LOCKED
mm: fix race between MADV_FREE reclaim and blkdev direct IO read
mm: generalize ARCH_HAS_FILTER_PGPROT
mm: unmap_mapping_range_tree() with i_mmap_rwsem shared
mm: warn on deleting redirtied only if accounted
mm/huge_memory: remove stale locking logic from __split_huge_pmd()
mm/huge_memory: remove stale page_trans_huge_mapcount()
mm/swapfile: remove stale reuse_swap_page()
mm/khugepaged: remove reuse_swap_page() usage
mm/huge_memory: streamline COW logic in do_huge_pmd_wp_page()
mm: streamline COW logic in do_swap_page()
mm: slightly clarify KSM logic in do_swap_page()
mm: optimize do_wp_page() for fresh pages in local LRU pagevecs
mm: optimize do_wp_page() for exclusive pages in the swapcache
mm/huge_memory: make is_transparent_hugepage() static
userfaultfd/selftests: enable hugetlb remap and remove event testing
selftests/vm: add hugetlb madvise MADV_DONTNEED MADV_REMOVE test
mm: enable MADV_DONTNEED for hugetlb mappings
kasan: disable LOCKDEP when printing reports
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git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux
Pull RISC-V updates from Palmer Dabbelt:
- Support for Sv57-based virtual memory.
- Various improvements for the MicroChip PolarFire SOC and the
associated Icicle dev board, which should allow upstream kernels to
boot without any additional modifications.
- An improved memmove() implementation.
- Support for the new Ssconfpmf and SBI PMU extensions, which allows
for a much more useful perf implementation on RISC-V systems.
- Support for restartable sequences.
* tag 'riscv-for-linus-5.18-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (36 commits)
rseq/selftests: Add support for RISC-V
RISC-V: Add support for restartable sequence
MAINTAINERS: Add entry for RISC-V PMU drivers
Documentation: riscv: Remove the old documentation
RISC-V: Add sscofpmf extension support
RISC-V: Add perf platform driver based on SBI PMU extension
RISC-V: Add RISC-V SBI PMU extension definitions
RISC-V: Add a simple platform driver for RISC-V legacy perf
RISC-V: Add a perf core library for pmu drivers
RISC-V: Add CSR encodings for all HPMCOUNTERS
RISC-V: Remove the current perf implementation
RISC-V: Improve /proc/cpuinfo output for ISA extensions
RISC-V: Do no continue isa string parsing without correct XLEN
RISC-V: Implement multi-letter ISA extension probing framework
RISC-V: Extract multi-letter extension names from "riscv, isa"
RISC-V: Minimal parser for "riscv, isa" strings
RISC-V: Correctly print supported extensions
riscv: Fixed misaligned memory access. Fixed pointer comparison.
MAINTAINERS: update riscv/microchip entry
riscv: dts: microchip: add new peripherals to icicle kit device tree
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git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull s390 updates from Vasily Gorbik:
- Raise minimum supported machine generation to z10, which comes with
various cleanups and code simplifications (usercopy/spectre
mitigation/etc).
- Rework extables and get rid of anonymous out-of-line fixups.
- Page table helpers cleanup. Add set_pXd()/set_pte() helper functions.
Covert pte_val()/pXd_val() macros to functions.
- Optimize kretprobe handling by avoiding extra kprobe on
__kretprobe_trampoline.
- Add support for CEX8 crypto cards.
- Allow to trigger AP bus rescan via writing to /sys/bus/ap/scans.
- Add CONFIG_EXPOLINE_EXTERN option to build the kernel without COMDAT
group sections which simplifies kpatch support.
- Always use the packed stack layout and extend kernel unwinder tests.
- Add sanity checks for ftrace code patching.
- Add s390dbf debug log for the vfio_ap device driver.
- Various virtual vs physical address confusion fixes.
- Various small fixes and improvements all over the code.
* tag 's390-5.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (69 commits)
s390/test_unwind: add kretprobe tests
s390/kprobes: Avoid additional kprobe in kretprobe handling
s390: convert ".insn" encoding to instruction names
s390: assume stckf is always present
s390/nospec: move to single register thunks
s390: raise minimum supported machine generation to z10
s390/uaccess: Add copy_from/to_user_key functions
s390/nospec: align and size extern thunks
s390/nospec: add an option to use thunk-extern
s390/nospec: generate single register thunks if possible
s390/pci: make zpci_set_irq()/zpci_clear_irq() static
s390: remove unused expoline to BC instructions
s390/irq: use assignment instead of cast
s390/traps: get rid of magic cast for per code
s390/traps: get rid of magic cast for program interruption code
s390/signal: fix typo in comments
s390/asm-offsets: remove unused defines
s390/test_unwind: avoid build warning with W=1
s390: remove .fixup section
s390/bpf: encode register within extable entry
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Pull Xtensa updates from Max Filippov:
- remove dependency on the compiler's libgcc
- allow selection of internal kernel ABI via Kconfig
- enable compiler plugins support for gcc-12 or newer
- various minor cleanups and fixes
* tag 'xtensa-20220325' of https://github.com/jcmvbkbc/linux-xtensa:
xtensa: define update_mmu_tlb function
xtensa: fix xtensa_wsr always writing 0
xtensa: enable plugin support
xtensa: clean up kernel exit assembly code
xtensa: rearrange NMI exit path
xtensa: merge stack alignment definitions
xtensa: fix DTC warning unit_address_format
xtensa: fix stop_machine_cpuslocked call in patch_text
xtensa: make secondary reset vector support conditional
xtensa: add kernel ABI selection to Kconfig
xtensa: don't link with libgcc
xtensa: add helpers for division, remainder and shifts
xtensa: add missing XCHAL_HAVE_WINDOWED check
xtensa: use XCHAL_NUM_AREGS as pt_regs::areg size
xtensa: rename PT_SIZE to PT_KERNEL_SIZE
xtensa: Remove unused early_read_config_byte() et al declarations
xtensa: use strscpy to copy strings
net: xtensa: use strscpy to copy strings
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git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman:
"Livepatch support for 32-bit is probably the standout new feature,
otherwise mostly just lots of bits and pieces all over the board.
There's a series of commits cleaning up function descriptor handling,
which touches a few other arches as well as LKDTM. It has acks from
Arnd, Kees and Helge.
Summary:
- Enforce kernel RO, and implement STRICT_MODULE_RWX for 603.
- Add support for livepatch to 32-bit.
- Implement CONFIG_DYNAMIC_FTRACE_WITH_ARGS.
- Merge vdso64 and vdso32 into a single directory.
- Fix build errors with newer binutils.
- Add support for UADDR64 relocations, which are emitted by some
toolchains. This allows powerpc to build with the latest lld.
- Fix (another) potential userspace r13 corruption in transactional
memory handling.
- Cleanups of function descriptor handling & related fixes to LKDTM.
Thanks to Abdul Haleem, Alexey Kardashevskiy, Anders Roxell, Aneesh
Kumar K.V, Anton Blanchard, Arnd Bergmann, Athira Rajeev, Bhaskar
Chowdhury, Cédric Le Goater, Chen Jingwen, Christophe JAILLET,
Christophe Leroy, Corentin Labbe, Daniel Axtens, Daniel Henrique
Barboza, David Dai, Fabiano Rosas, Ganesh Goudar, Guo Zhengkui, Hangyu
Hua, Haren Myneni, Hari Bathini, Igor Zhbanov, Jakob Koschel, Jason
Wang, Jeremy Kerr, Joachim Wiberg, Jordan Niethe, Julia Lawall, Kajol
Jain, Kees Cook, Laurent Dufour, Madhavan Srinivasan, Mamatha Inamdar,
Maxime Bizon, Maxim Kiselev, Maxim Kochetkov, Michal Suchanek,
Nageswara R Sastry, Nathan Lynch, Naveen N. Rao, Nicholas Piggin,
Nour-eddine Taleb, Paul Menzel, Ping Fang, Pratik R. Sampat, Randy
Dunlap, Ritesh Harjani, Rohan McLure, Russell Currey, Sachin Sant,
Segher Boessenkool, Shivaprasad G Bhat, Sourabh Jain, Thierry Reding,
Tobias Waldekranz, Tyrel Datwyler, Vaibhav Jain, Vladimir Oltean,
Wedson Almeida Filho, and YueHaibing"
* tag 'powerpc-5.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (179 commits)
powerpc/pseries: Fix use after free in remove_phb_dynamic()
powerpc/time: improve decrementer clockevent processing
powerpc/time: Fix KVM host re-arming a timer beyond decrementer range
powerpc/tm: Fix more userspace r13 corruption
powerpc/xive: fix return value of __setup handler
powerpc/64: Add UADDR64 relocation support
powerpc: 8xx: fix a return value error in mpc8xx_pic_init
powerpc/ps3: remove unneeded semicolons
powerpc/64: Force inlining of prevent_user_access() and set_kuap()
powerpc/bitops: Force inlining of fls()
powerpc: declare unmodified attribute_group usages const
powerpc/spufs: Fix build warning when CONFIG_PROC_FS=n
powerpc/secvar: fix refcount leak in format_show()
powerpc/64e: Tie PPC_BOOK3E_64 to PPC_FSL_BOOK3E
powerpc: Move C prototypes out of asm-prototypes.h
powerpc/kexec: Declare kexec_paca static
powerpc/smp: Declare current_set static
powerpc: Cleanup asm-prototypes.c
powerpc/ftrace: Use STK_GOT in ftrace_mprofile.S
powerpc/ftrace: Regroup PPC64 specific operations in ftrace_mprofile.S
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git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux
Pull MIPS updates from Thomas Bogendoerfer:
- added support for QCN550x (ath79)
- enabled KCSAN
- removed TX39XX support
- various cleanups and fixes
* tag 'mips_5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux: (31 commits)
MIPS: Fix build error for loongson64 and sgi-ip27
MIPS: ingenic: correct unit node address
MIPS: Fix wrong comments in asm/prom.h
MIPS: Remove redundant definitions of device_tree_init()
MIPS: Remove redundant check in device_tree_init()
MIPS: pgalloc: fix memory leak caused by pgd_free()
MIPS: RB532: fix return value of __setup handler
MIPS: Only use current_stack_pointer on GCC
MIPS: boot/compressed: Use array reference for image bounds
mips: cdmm: Fix refcount leak in mips_cdmm_phys_base
mips: remove reference to "newer Loongson-3"
mips: Always permit to build u-boot images
MIPS: Sanitise Cavium switch cases in TLB handler synthesizers
DEC: Limit PMAX memory probing to R3k systems
mips: DEC: honor CONFIG_MIPS_FP_SUPPORT=n
MIPS: fix fortify panic when copying asm exception handlers
mips: ralink: fix a refcount leak in ill_acc_of_setup()
mips: Implement "current_stack_pointer"
MIPS: Remove TX39XX support
MIPS: Modernize READ_IMPLIES_EXEC
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git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu
Pull iommu updates from Joerg Roedel:
- IOMMU Core changes:
- Removal of aux domain related code as it is basically dead and
will be replaced by iommu-fd framework
- Split of iommu_ops to carry domain-specific call-backs separatly
- Cleanup to remove useless ops->capable implementations
- Improve 32-bit free space estimate in iova allocator
- Intel VT-d updates:
- Various cleanups of the driver
- Support for ATS of SoC-integrated devices listed in ACPI/SATC
table
- ARM SMMU updates:
- Fix SMMUv3 soft lockup during continuous stream of events
- Fix error path for Qualcomm SMMU probe()
- Rework SMMU IRQ setup to prepare the ground for PMU support
- Minor cleanups and refactoring
- AMD IOMMU driver:
- Some minor cleanups and error-handling fixes
- Rockchip IOMMU driver:
- Use standard driver registration
- MSM IOMMU driver:
- Minor cleanup and change to standard driver registration
- Mediatek IOMMU driver:
- Fixes for IOTLB flushing logic
* tag 'iommu-updates-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu: (47 commits)
iommu/amd: Improve amd_iommu_v2_exit()
iommu/amd: Remove unused struct fault.devid
iommu/amd: Clean up function declarations
iommu/amd: Call memunmap in error path
iommu/arm-smmu: Account for PMU interrupts
iommu/vt-d: Enable ATS for the devices in SATC table
iommu/vt-d: Remove unused function intel_svm_capable()
iommu/vt-d: Add missing "__init" for rmrr_sanity_check()
iommu/vt-d: Move intel_iommu_ops to header file
iommu/vt-d: Fix indentation of goto labels
iommu/vt-d: Remove unnecessary prototypes
iommu/vt-d: Remove unnecessary includes
iommu/vt-d: Remove DEFER_DEVICE_DOMAIN_INFO
iommu/vt-d: Remove domain and devinfo mempool
iommu/vt-d: Remove iova_cache_get/put()
iommu/vt-d: Remove finding domain in dmar_insert_one_dev_info()
iommu/vt-d: Remove intel_iommu::domains
iommu/mediatek: Always tlb_flush_all when each PM resume
iommu/mediatek: Add tlb_lock in tlb_flush_all
iommu/mediatek: Remove the power status checking in tlb flush all
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Pull SCSI updates from James Bottomley:
"This series consists of the usual driver updates (qla2xxx, pm8001,
libsas, smartpqi, scsi_debug, lpfc, iscsi, mpi3mr) plus minor updates
and bug fixes.
The high blast radius core update is the removal of write same, which
affects block and several non-SCSI devices. The other big change,
which is more local, is the removal of the SCSI pointer"
* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (281 commits)
scsi: scsi_ioctl: Drop needless assignment in sg_io()
scsi: bsg: Drop needless assignment in scsi_bsg_sg_io_fn()
scsi: lpfc: Copyright updates for 14.2.0.0 patches
scsi: lpfc: Update lpfc version to 14.2.0.0
scsi: lpfc: SLI path split: Refactor BSG paths
scsi: lpfc: SLI path split: Refactor Abort paths
scsi: lpfc: SLI path split: Refactor SCSI paths
scsi: lpfc: SLI path split: Refactor CT paths
scsi: lpfc: SLI path split: Refactor misc ELS paths
scsi: lpfc: SLI path split: Refactor VMID paths
scsi: lpfc: SLI path split: Refactor FDISC paths
scsi: lpfc: SLI path split: Refactor LS_RJT paths
scsi: lpfc: SLI path split: Refactor LS_ACC paths
scsi: lpfc: SLI path split: Refactor the RSCN/SCR/RDF/EDC/FARPR paths
scsi: lpfc: SLI path split: Refactor PLOGI/PRLI/ADISC/LOGO paths
scsi: lpfc: SLI path split: Refactor base ELS paths and the FLOGI path
scsi: lpfc: SLI path split: Introduce lpfc_prep_wqe
scsi: lpfc: SLI path split: Refactor fast and slow paths to native SLI4
scsi: lpfc: SLI path split: Refactor lpfc_iocbq
scsi: lpfc: Use kcalloc()
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git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm
Pull device mapper updates from Mike Snitzer:
- Significant refactoring and fixing of how DM core does bio-based IO
accounting with focus on fixing wildly inaccurate IO stats for
dm-crypt (and other DM targets that defer bio submission in their own
workqueues). End result is proper IO accounting, made possible by
targets being updated to use the new dm_submit_bio_remap() interface.
- Add hipri bio polling support (REQ_POLLED) to bio-based DM.
- Reduce dm_io and dm_target_io structs so that a single dm_io (which
contains dm_target_io and first clone bio) weighs in at 256 bytes.
For reference the bio struct is 128 bytes.
- Various other small cleanups, fixes or improvements in DM core and
targets.
- Update MAINTAINERS with my kernel.org email address to allow
distinction between my "upstream" and "Red" Hats.
* tag 'for-5.18/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (46 commits)
dm: consolidate spinlocks in dm_io struct
dm: reduce size of dm_io and dm_target_io structs
dm: switch dm_target_io booleans over to proper flags
dm: switch dm_io booleans over to proper flags
dm: update email address in MAINTAINERS
dm: return void from __send_empty_flush
dm: factor out dm_io_complete
dm cache: use dm_submit_bio_remap
dm: simplify dm_sumbit_bio_remap interface
dm thin: use dm_submit_bio_remap
dm: add WARN_ON_ONCE to dm_submit_bio_remap
dm: support bio polling
block: add ->poll_bio to block_device_operations
dm mpath: use DMINFO instead of printk with KERN_INFO
dm: stop using bdevname
dm-zoned: remove the ->name field in struct dmz_dev
dm: remove unnecessary local variables in __bind
dm: requeue IO if mapping table not yet available
dm io: remove stale comment block for dm_io()
dm thin metadata: remove unused dm_thin_remove_block and __remove
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Pull rdma updates from Jason Gunthorpe:
- Minor bug fixes in mlx5, mthca, pvrdma, rtrs, mlx4, hfi1, hns
- Minor cleanups: coding style, useless includes and documentation
- Reorganize how multicast processing works in rxe
- Replace a red/black tree with xarray in rxe which improves performance
- DSCP support and HW address handle re-use in irdma
- Simplify the mailbox command handling in hns
- Simplify iser now that FMR is eliminated
* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma: (93 commits)
RDMA/nldev: Prevent underflow in nldev_stat_set_counter_dynamic_doit()
IB/iser: Fix error flow in case of registration failure
IB/iser: Generalize map/unmap dma tasks
IB/iser: Use iser_fr_desc as registration context
IB/iser: Remove iser_reg_data_sg helper function
RDMA/rxe: Use standard names for ref counting
RDMA/rxe: Replace red-black trees by xarrays
RDMA/rxe: Shorten pool names in rxe_pool.c
RDMA/rxe: Move max_elem into rxe_type_info
RDMA/rxe: Replace obj by elem in declaration
RDMA/rxe: Delete _locked() APIs for pool objects
RDMA/rxe: Reverse the sense of RXE_POOL_NO_ALLOC
RDMA/rxe: Replace mr by rkey in responder resources
RDMA/rxe: Fix ref error in rxe_av.c
RDMA/hns: Use the reserved loopback QPs to free MR before destroying MPT
RDMA/irdma: Add support for address handle re-use
RDMA/qib: Fix typos in comments
RDMA/mlx5: Fix memory leak in error flow for subscribe event routine
Revert "RDMA/core: Fix ib_qp_usecnt_dec() called when error"
RDMA/rxe: Remove useless argument for update_state()
...
|
|
Instead of having each time that wants to use ksft_exit() have to figure
out the internals of kselftest.h, add the helper ksft_finished() that
makes sure the passes, xfails, and skips are equal to the test plan count.
Link: https://lkml.kernel.org/r/20220201013717.2464392-1-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
MADV_DONTNEED historically rejects mlocked ranges, but with MLOCK_ONFAULT
and MCL_ONFAULT allowing to mlock without populating, there are valid use
cases for depopulating locked ranges as well.
Users mlock memory to protect secrets. There are allocators for secure
buffers that want in-use memory generally mlocked, but cleared and
invalidated memory to give up the physical pages. This could be done with
explicit munlock -> mlock calls on free -> alloc of course, but that adds
two unnecessary syscalls, heavy mmap_sem write locks, vma splits and
re-merges - only to get rid of the backing pages.
Users also mlockall(MCL_ONFAULT) to suppress sustained paging, but are
okay with on-demand initial population. It seems valid to selectively
free some memory during the lifetime of such a process, without having to
mess with its overall policy.
Why add a separate flag? Isn't this a pretty niche usecase?
- MADV_DONTNEED has been bailing on locked vmas forever. It's at least
conceivable that someone, somewhere is relying on mlock to protect
data from perhaps broader invalidation calls. Changing this behavior
now could lead to quiet data corruption.
- It also clarifies expectations around MADV_FREE and maybe
MADV_REMOVE. It avoids the situation where one quietly behaves
different than the others. MADV_FREE_LOCKED can be added later.
- The combination of mlock() and madvise() in the first place is
probably niche. But where it happens, I'd say that dropping pages
from a locked region once they don't contain secrets or won't page
anymore is much saner than relying on mlock to protect memory from
speculative or errant invalidation calls. It's just that we can't
change the default behavior because of the two previous points.
Given that, an explicit new flag seems to make the most sense.
[hannes@cmpxchg.org: fix mips build]
Link: https://lkml.kernel.org/r/20220304171912.305060-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Problem:
=======
Userspace might read the zero-page instead of actual data from a direct IO
read on a block device if the buffers have been called madvise(MADV_FREE)
on earlier (this is discussed below) due to a race between page reclaim on
MADV_FREE and blkdev direct IO read.
- Race condition:
==============
During page reclaim, the MADV_FREE page check in try_to_unmap_one() checks
if the page is not dirty, then discards its rmap PTE(s) (vs. remap back
if the page is dirty).
However, after try_to_unmap_one() returns to shrink_page_list(), it might
keep the page _anyway_ if page_ref_freeze() fails (it expects exactly
_one_ page reference, from the isolation for page reclaim).
Well, blkdev_direct_IO() gets references for all pages, and on READ
operations it only sets them dirty _later_.
So, if MADV_FREE'd pages (i.e., not dirty) are used as buffers for direct
IO read from block devices, and page reclaim happens during
__blkdev_direct_IO[_simple]() exactly AFTER bio_iov_iter_get_pages()
returns, but BEFORE the pages are set dirty, the situation happens.
The direct IO read eventually completes. Now, when userspace reads the
buffers, the PTE is no longer there and the page fault handler
do_anonymous_page() services that with the zero-page, NOT the data!
A synthetic reproducer is provided.
- Page faults:
===========
If page reclaim happens BEFORE bio_iov_iter_get_pages() the issue doesn't
happen, because that faults-in all pages as writeable, so
do_anonymous_page() sets up a new page/rmap/PTE, and that is used by
direct IO. The userspace reads don't fault as the PTE is there (thus
zero-page is not used/setup).
But if page reclaim happens AFTER it / BEFORE setting pages dirty, the PTE
is no longer there; the subsequent page faults can't help:
The data-read from the block device probably won't generate faults due to
DMA (no MMU) but even in the case it wouldn't use DMA, that happens on
different virtual addresses (not user-mapped addresses) because `struct
bio_vec` stores `struct page` to figure addresses out (which are different
from user-mapped addresses) for the read.
Thus userspace reads (to user-mapped addresses) still fault, then
do_anonymous_page() gets another `struct page` that would address/ map to
other memory than the `struct page` used by `struct bio_vec` for the read.
(The original `struct page` is not available, since it wasn't freed, as
page_ref_freeze() failed due to more page refs. And even if it were
available, its data cannot be trusted anymore.)
Solution:
========
One solution is to check for the expected page reference count in
try_to_unmap_one().
There should be one reference from the isolation (that is also checked in
shrink_page_list() with page_ref_freeze()) plus one or more references
from page mapping(s) (put in discard: label). Further references mean
that rmap/PTE cannot be unmapped/nuked.
(Note: there might be more than one reference from mapping due to
fork()/clone() without CLONE_VM, which use the same `struct page` for
references, until the copy-on-write page gets copied.)
So, additional page references (e.g., from direct IO read) now prevent the
rmap/PTE from being unmapped/dropped; similarly to the page is not freed
per shrink_page_list()/page_ref_freeze()).
- Races and Barriers:
==================
The new check in try_to_unmap_one() should be safe in races with
bio_iov_iter_get_pages() in get_user_pages() fast and slow paths, as it's
done under the PTE lock.
The fast path doesn't take the lock, but it checks if the PTE has changed
and if so, it drops the reference and leaves the page for the slow path
(which does take that lock).
The fast path requires synchronization w/ full memory barrier: it writes
the page reference count first then it reads the PTE later, while
try_to_unmap() writes PTE first then it reads page refcount.
And a second barrier is needed, as the page dirty flag should not be read
before the page reference count (as in __remove_mapping()). (This can be
a load memory barrier only; no writes are involved.)
Call stack/comments:
- try_to_unmap_one()
- page_vma_mapped_walk()
- map_pte() # see pte_offset_map_lock():
pte_offset_map()
spin_lock()
- ptep_get_and_clear() # write PTE
- smp_mb() # (new barrier) GUP fast path
- page_ref_count() # (new check) read refcount
- page_vma_mapped_walk_done() # see pte_unmap_unlock():
pte_unmap()
spin_unlock()
- bio_iov_iter_get_pages()
- __bio_iov_iter_get_pages()
- iov_iter_get_pages()
- get_user_pages_fast()
- internal_get_user_pages_fast()
# fast path
- lockless_pages_from_mm()
- gup_{pgd,p4d,pud,pmd,pte}_range()
ptep = pte_offset_map() # not _lock()
pte = ptep_get_lockless(ptep)
page = pte_page(pte)
try_grab_compound_head(page) # inc refcount
# (RMW/barrier
# on success)
if (pte_val(pte) != pte_val(*ptep)) # read PTE
put_compound_head(page) # dec refcount
# go slow path
# slow path
- __gup_longterm_unlocked()
- get_user_pages_unlocked()
- __get_user_pages_locked()
- __get_user_pages()
- follow_{page,p4d,pud,pmd}_mask()
- follow_page_pte()
ptep = pte_offset_map_lock()
pte = *ptep
page = vm_normal_page(pte)
try_grab_page(page) # inc refcount
pte_unmap_unlock()
- Huge Pages:
==========
Regarding transparent hugepages, that logic shouldn't change, as MADV_FREE
(aka lazyfree) pages are PageAnon() && !PageSwapBacked()
(madvise_free_pte_range() -> mark_page_lazyfree() -> lru_lazyfree_fn())
thus should reach shrink_page_list() -> split_huge_page_to_list() before
try_to_unmap[_one](), so it deals with normal pages only.
(And in case unlikely/TTU_SPLIT_HUGE_PMD/split_huge_pmd_address() happens,
which should not or be rare, the page refcount should be greater than
mapcount: the head page is referenced by tail pages. That also prevents
checking the head `page` then incorrectly call page_remove_rmap(subpage)
for a tail page, that isn't even in the shrink_page_list()'s page_list (an
effect of split huge pmd/pmvw), as it might happen today in this unlikely
scenario.)
MADV_FREE'd buffers:
===================
So, back to the "if MADV_FREE pages are used as buffers" note. The case
is arguable, and subject to multiple interpretations.
The madvise(2) manual page on the MADV_FREE advice value says:
1) 'After a successful MADV_FREE ... data will be lost when
the kernel frees the pages.'
2) 'the free operation will be canceled if the caller writes
into the page' / 'subsequent writes ... will succeed and
then [the] kernel cannot free those dirtied pages'
3) 'If there is no subsequent write, the kernel can free the
pages at any time.'
Thoughts, questions, considerations... respectively:
1) Since the kernel didn't actually free the page (page_ref_freeze()
failed), should the data not have been lost? (on userspace read.)
2) Should writes performed by the direct IO read be able to cancel
the free operation?
- Should the direct IO read be considered as 'the caller' too,
as it's been requested by 'the caller'?
- Should the bio technique to dirty pages on return to userspace
(bio_check_pages_dirty() is called/used by __blkdev_direct_IO())
be considered in another/special way here?
3) Should an upcoming write from a previously requested direct IO
read be considered as a subsequent write, so the kernel should
not free the pages? (as it's known at the time of page reclaim.)
And lastly:
Technically, the last point would seem a reasonable consideration and
balance, as the madvise(2) manual page apparently (and fairly) seem to
assume that 'writes' are memory access from the userspace process (not
explicitly considering writes from the kernel or its corner cases; again,
fairly).. plus the kernel fix implementation for the corner case of the
largely 'non-atomic write' encompassed by a direct IO read operation, is
relatively simple; and it helps.
Reproducer:
==========
@ test.c (simplified, but works)
#define _GNU_SOURCE
#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/mman.h>
int main() {
int fd, i;
char *buf;
fd = open(DEV, O_RDONLY | O_DIRECT);
buf = mmap(NULL, BUF_SIZE, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
for (i = 0; i < BUF_SIZE; i += PAGE_SIZE)
buf[i] = 1; // init to non-zero
madvise(buf, BUF_SIZE, MADV_FREE);
read(fd, buf, BUF_SIZE);
for (i = 0; i < BUF_SIZE; i += PAGE_SIZE)
printf("%p: 0x%x\n", &buf[i], buf[i]);
return 0;
}
@ block/fops.c (formerly fs/block_dev.c)
+#include <linux/swap.h>
...
... __blkdev_direct_IO[_simple](...)
{
...
+ if (!strcmp(current->comm, "good"))
+ shrink_all_memory(ULONG_MAX);
+
ret = bio_iov_iter_get_pages(...);
+
+ if (!strcmp(current->comm, "bad"))
+ shrink_all_memory(ULONG_MAX);
...
}
@ shell
# NUM_PAGES=4
# PAGE_SIZE=$(getconf PAGE_SIZE)
# yes | dd of=test.img bs=${PAGE_SIZE} count=${NUM_PAGES}
# DEV=$(losetup -f --show test.img)
# gcc -DDEV=\"$DEV\" \
-DBUF_SIZE=$((PAGE_SIZE * NUM_PAGES)) \
-DPAGE_SIZE=${PAGE_SIZE} \
test.c -o test
# od -tx1 $DEV
0000000 79 0a 79 0a 79 0a 79 0a 79 0a 79 0a 79 0a 79 0a
*
0040000
# mv test good
# ./good
0x7f7c10418000: 0x79
0x7f7c10419000: 0x79
0x7f7c1041a000: 0x79
0x7f7c1041b000: 0x79
# mv good bad
# ./bad
0x7fa1b8050000: 0x0
0x7fa1b8051000: 0x0
0x7fa1b8052000: 0x0
0x7fa1b8053000: 0x0
Note: the issue is consistent on v5.17-rc3, but it's intermittent with the
support of MADV_FREE on v4.5 (60%-70% error; needs swap). [wrap
do_direct_IO() in do_blockdev_direct_IO() @ fs/direct-io.c].
- v5.17-rc3:
# for i in {1..1000}; do ./good; done \
| cut -d: -f2 | sort | uniq -c
4000 0x79
# mv good bad
# for i in {1..1000}; do ./bad; done \
| cut -d: -f2 | sort | uniq -c
4000 0x0
# free | grep Swap
Swap: 0 0 0
- v4.5:
# for i in {1..1000}; do ./good; done \
| cut -d: -f2 | sort | uniq -c
4000 0x79
# mv good bad
# for i in {1..1000}; do ./bad; done \
| cut -d: -f2 | sort | uniq -c
2702 0x0
1298 0x79
# swapoff -av
swapoff /swap
# for i in {1..1000}; do ./bad; done \
| cut -d: -f2 | sort | uniq -c
4000 0x79
Ceph/TCMalloc:
=============
For documentation purposes, the use case driving the analysis/fix is Ceph
on Ubuntu 18.04, as the TCMalloc library there still uses MADV_FREE to
release unused memory to the system from the mmap'ed page heap (might be
committed back/used again; it's not munmap'ed.) - PageHeap::DecommitSpan()
-> TCMalloc_SystemRelease() -> madvise() - PageHeap::CommitSpan() ->
TCMalloc_SystemCommit() -> do nothing.
Note: TCMalloc switched back to MADV_DONTNEED a few commits after the
release in Ubuntu 18.04 (google-perftools/gperftools 2.5), so the issue
just 'disappeared' on Ceph on later Ubuntu releases but is still present
in the kernel, and can be hit by other use cases.
The observed issue seems to be the old Ceph bug #22464 [1], where checksum
mismatches are observed (and instrumentation with buffer dumps shows
zero-pages read from mmap'ed/MADV_FREE'd page ranges).
The issue in Ceph was reasonably deemed a kernel bug (comment #50) and
mostly worked around with a retry mechanism, but other parts of Ceph could
still hit that (rocksdb). Anyway, it's less likely to be hit again as
TCMalloc switched out of MADV_FREE by default.
(Some kernel versions/reports from the Ceph bug, and relation with
the MADV_FREE introduction/changes; TCMalloc versions not checked.)
- 4.4 good
- 4.5 (madv_free: introduction)
- 4.9 bad
- 4.10 good? maybe a swapless system
- 4.12 (madv_free: no longer free instantly on swapless systems)
- 4.13 bad
[1] https://tracker.ceph.com/issues/22464
Thanks:
======
Several people contributed to analysis/discussions/tests/reproducers in
the first stages when drilling down on ceph/tcmalloc/linux kernel:
- Dan Hill
- Dan Streetman
- Dongdong Tao
- Gavin Guo
- Gerald Yang
- Heitor Alves de Siqueira
- Ioanna Alifieraki
- Jay Vosburgh
- Matthew Ruffell
- Ponnuvel Palaniyappan
Reviews, suggestions, corrections, comments:
- Minchan Kim
- Yu Zhao
- Huang, Ying
- John Hubbard
- Christoph Hellwig
[mfo@canonical.com: v4]
Link: https://lkml.kernel.org/r/20220209202659.183418-1-mfo@canonical.comLink: https://lkml.kernel.org/r/20220131230255.789059-1-mfo@canonical.com
Fixes: 802a3a92ad7a ("mm: reclaim MADV_FREE pages")
Signed-off-by: Mauricio Faria de Oliveira <mfo@canonical.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Dan Hill <daniel.hill@canonical.com>
Cc: Dan Streetman <dan.streetman@canonical.com>
Cc: Dongdong Tao <dongdong.tao@canonical.com>
Cc: Gavin Guo <gavin.guo@canonical.com>
Cc: Gerald Yang <gerald.yang@canonical.com>
Cc: Heitor Alves de Siqueira <halves@canonical.com>
Cc: Ioanna Alifieraki <ioanna-maria.alifieraki@canonical.com>
Cc: Jay Vosburgh <jay.vosburgh@canonical.com>
Cc: Matthew Ruffell <matthew.ruffell@canonical.com>
Cc: Ponnuvel Palaniyappan <ponnuvel.palaniyappan@canonical.com>
Cc: <stable@vger.kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
ARCH_HAS_FILTER_PGPROT config has duplicate definitions on platforms that
subscribe it. Instead make it a generic config option which can be
selected on applicable platforms when required.
Link: https://lkml.kernel.org/r/1643004823-16441-1-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Revert 48ec833b7851 ("Revert "mm/memory.c: share the i_mmap_rwsem"") to
reinstate c8475d144abb ("mm/memory.c: share the i_mmap_rwsem"): the
unmap_mapping_range family of functions do the unmapping of user pages
(ultimately via zap_page_range_single) without modifying the interval tree
itself, and unmapping races are necessarily guarded by page table lock,
thus the i_mmap_rwsem should be shared in unmap_mapping_pages() and
unmap_mapping_folio().
Commit 48ec833b7851 was intended as a short-term measure, allowing the
other shared lock changes into 3.19 final, before investigating three
trinity crashes, one of which had been bisected to commit c8475d144ab:
[1] https://lkml.org/lkml/2014/11/14/342
https://lore.kernel.org/lkml/5466142C.60100@oracle.com/
[2] https://lkml.org/lkml/2014/12/22/213
https://lore.kernel.org/lkml/549832E2.8060609@oracle.com/
[3] https://lkml.org/lkml/2014/12/9/741
https://lore.kernel.org/lkml/5487ACC5.1010002@oracle.com/
Two of those were Bad page states: free_pages_prepare() found PG_mlocked
still set - almost certain to have been fixed by 4.4 commit b87537d9e2fe
("mm: rmap use pte lock not mmap_sem to set PageMlocked"). The NULL deref
on rwsem in [2]: unclear, only happened once, not bisected to c8475d144ab.
No change to the i_mmap_lock_write() around __unmap_hugepage_range_final()
in unmap_single_vma(): IIRC that's a special usage, helping to serialize
hugetlbfs page table sharing, not to be dabbled with lightly. No change
to other uses of i_mmap_lock_write() by hugetlbfs.
I am not aware of any significant gains from the concurrency allowed by
this commit: it is submitted more to resolve an ancient misunderstanding.
Link: https://lkml.kernel.org/r/e4a5e356-6c87-47b2-3ce8-c2a95ae84e20@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
filemap_unaccount_folio() has a WARN_ON_ONCE(folio_test_dirty(folio)). It
is good to warn of late dirtying on a persistent filesystem, but late
dirtying on tmpfs can only lose data which is expected to be thrown away;
and it's a pity if that warning comes ONCE on tmpfs, then hides others
which really matter. Make it conditional on mapping_cap_writeback().
Cleanup: then folio_account_cleaned() no longer needs to check that for
itself, and so no longer needs to know the mapping.
Link: https://lkml.kernel.org/r/b5a1106c-7226-a5c6-ad41-ad4832cae1f@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Jan Kara <jack@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Let's remove the stale logic that was required for reuse_swap_page().
[akpm@linux-foundation.org: simplification, per Yang Shi]
Link: https://lkml.kernel.org/r/20220131162940.210846-10-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Liang Zhang <zhangliang5@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
All users are gone, let's remove it.
Link: https://lkml.kernel.org/r/20220131162940.210846-9-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Liang Zhang <zhangliang5@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
All users are gone, let's remove it. We'll let SWP_STABLE_WRITES stick
around for now, as it might come in handy in the near future.
Link: https://lkml.kernel.org/r/20220131162940.210846-8-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Liang Zhang <zhangliang5@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
reuse_swap_page() currently indicates if we can write to an anon page
without COW. A COW is required if the page is shared by multiple
processes (either already mapped or via swap entries) or if there is
concurrent writeback that cannot tolerate concurrent page modifications.
However, in the context of khugepaged we're not actually going to write to
a read-only mapped page, we'll copy the page content to our newly
allocated THP and map that THP writable. All we have to make sure is that
the read-only mapped page we're about to copy won't get reused by another
process sharing the page, otherwise, page content would get modified. But
that is already guaranteed via multiple mechanisms (e.g., holding a
reference, holding the page lock, removing the rmap after copying the
page).
The swapcache handling was introduced in commit 10359213d05a ("mm:
incorporate read-only pages into transparent huge pages") and it sounds
like it merely wanted to mimic what do_swap_page() would do when trying to
map a page obtained via the swapcache writable.
As that logic is unnecessary, let's just remove it, removing the last user
of reuse_swap_page().
Link: https://lkml.kernel.org/r/20220131162940.210846-7-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Liang Zhang <zhangliang5@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
We currently have a different COW logic for anon THP than we have for
ordinary anon pages in do_wp_page(): the effect is that the issue reported
in CVE-2020-29374 is currently still possible for anon THP: an unintended
information leak from the parent to the child.
Let's apply the same logic (page_count() == 1), with similar optimizations
to remove additional references first as we really want to avoid
PTE-mapping the THP and copying individual pages best we can.
If we end up with a page that has page_count() != 1, we'll have to PTE-map
the THP and fallback to do_wp_page(), which will always copy the page.
Note that KSM does not apply to THP.
I. Interaction with the swapcache and writeback
While a THP is in the swapcache, the swapcache holds one reference on each
subpage of the THP. So with PageSwapCache() set, we expect as many
additional references as we have subpages. If we manage to remove the THP
from the swapcache, all these references will be gone.
Usually, a THP is not split when entered into the swapcache and stays a
compound page. However, try_to_unmap() will PTE-map the THP and use PTE
swap entries. There are no PMD swap entries for that purpose,
consequently, we always only swapin subpages into PTEs.
Removing a page from the swapcache can fail either when there are
remaining swap entries (in which case COW is the right thing to do) or if
the page is currently under writeback.
Having a locked, R/O PMD-mapped THP that is in the swapcache seems to be
possible only in corner cases, for example, if try_to_unmap() failed after
adding the page to the swapcache. However, it's comparatively easy to
handle.
As we have to fully unmap a THP before starting writeback, and swapin is
always done on the PTE level, we shouldn't find a R/O PMD-mapped THP in
the swapcache that is under writeback. This should at least leave
writeback out of the picture.
II. Interaction with GUP references
Having a R/O PMD-mapped THP with GUP references (i.e., R/O references)
will result in PTE-mapping the THP on a write fault. Similar to ordinary
anon pages, do_wp_page() will have to copy sub-pages and result in a
disconnect between the GUP references and the pages actually mapped into
the page tables. To improve the situation in the future, we'll need
additional handling to mark anonymous pages as definitely exclusive to a
single process, only allow GUP pins on exclusive anon pages, and disallow
sharing of exclusive anon pages with GUP pins e.g., during fork().
III. Interaction with references from LRU pagevecs
There is no need to try draining the (local) LRU pagevecs in case we would
stumble over a !PageLRU() page: folio_add_lru() and friends will always
flush the affected pagevec after adding a compound page to it immediately
-- pagevec_add_and_need_flush() always returns "true" for them. Note that
the LRU pagevecs will hold a reference on the compound page for a very
short time, between adding the page to the pagevec and draining it
immediately afterwards.
IV. Interaction with speculative/temporary references
Similar to ordinary anon pages, other speculative/temporary references on
the THP, for example, from the pagecache or page migration code, will
disallow exclusive reuse of the page. We'll have to PTE-map the THP.
Link: https://lkml.kernel.org/r/20220131162940.210846-6-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Liang Zhang <zhangliang5@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Currently we have a different COW logic when:
* triggering a read-fault to swapin first and then trigger a write-fault
-> do_swap_page() + do_wp_page()
* triggering a write-fault to swapin
-> do_swap_page() + do_wp_page() only if we fail reuse in do_swap_page()
The COW logic in do_swap_page() is different than our reuse logic in
do_wp_page(). The COW logic in do_wp_page() -- page_count() == 1 -- makes
currently sure that we certainly don't have a remaining reference, e.g.,
via GUP, on the target page we want to reuse: if there is any unexpected
reference, we have to copy to avoid information leaks.
As do_swap_page() behaves differently, in environments with swap enabled
we can currently have an unintended information leak from the parent to
the child, similar as known from CVE-2020-29374:
1. Parent writes to anonymous page
-> Page is mapped writable and modified
2. Page is swapped out
-> Page is unmapped and replaced by swap entry
3. fork()
-> Swap entries are copied to child
4. Child pins page R/O
-> Page is mapped R/O into child
5. Child unmaps page
-> Child still holds GUP reference
6. Parent writes to page
-> Page is reused in do_swap_page()
-> Child can observe changes
Exchanging 2. and 3. should have the same effect.
Let's apply the same COW logic as in do_wp_page(), conditionally trying to
remove the page from the swapcache after freeing the swap entry, however,
before actually mapping our page. We can change the order now that we use
try_to_free_swap(), which doesn't care about the mapcount, instead of
reuse_swap_page().
To handle references from the LRU pagevecs, conditionally drain the local
LRU pagevecs when required, however, don't consider the page_count() when
deciding whether to drain to keep it simple for now.
Link: https://lkml.kernel.org/r/20220131162940.210846-5-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Liang Zhang <zhangliang5@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Let's make it clearer that KSM might only have to copy a page in case we
have a page in the swapcache, not if we allocated a fresh page and
bypassed the swapcache. While at it, add a comment why this is usually
necessary and merge the two swapcache conditions.
[akpm@linux-foundation.org: fix comment, per David]
Link: https://lkml.kernel.org/r/20220131162940.210846-4-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Liang Zhang <zhangliang5@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
For example, if a page just got swapped in via a read fault, the LRU
pagevecs might still hold a reference to the page. If we trigger a write
fault on such a page, the additional reference from the LRU pagevecs will
prohibit reusing the page.
Let's conditionally drain the local LRU pagevecs when we stumble over a
!PageLRU() page. We cannot easily drain remote LRU pagevecs and it might
not be desirable performance-wise. Consequently, this will only avoid
copying in some cases.
Add a simple "page_count(page) > 3" check first but keep the
"page_count(page) > 1 + PageSwapCache(page)" check in place, as we want to
minimize cases where we remove a page from the swapcache but won't be able
to reuse it, for example, because another process has it mapped R/O, to
not affect reclaim.
We cannot easily handle the following cases and we will always have to
copy:
(1) The page is referenced in the LRU pagevecs of other CPUs. We really
would have to drain the LRU pagevecs of all CPUs -- most probably
copying is much cheaper.
(2) The page is already PageLRU() but is getting moved between LRU
lists, for example, for activation (e.g., mark_page_accessed()),
deactivation (MADV_COLD), or lazyfree (MADV_FREE). We'd have to
drain mostly unconditionally, which might be bad performance-wise.
Most probably this won't happen too often in practice.
Note that there are other reasons why an anon page might temporarily not
be PageLRU(): for example, compaction and migration have to isolate LRU
pages from the LRU lists first (isolate_lru_page()), moving them to
temporary local lists and clearing PageLRU() and holding an additional
reference on the page. In that case, we'll always copy.
This change seems to be fairly effective with the reproducer [1] shared by
Nadav, as long as writeback is done synchronously, for example, using
zram. However, with asynchronous writeback, we'll usually fail to free
the swapcache because the page is still under writeback: something we
cannot easily optimize for, and maybe it's not really relevant in
practice.
[1] https://lkml.kernel.org/r/0480D692-D9B2-429A-9A88-9BBA1331AC3A@gmail.com
Link: https://lkml.kernel.org/r/20220131162940.210846-3-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Liang Zhang <zhangliang5@huawei.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Patch series "mm: COW fixes part 1: fix the COW security issue for THP and swap", v3.
This series attempts to optimize and streamline the COW logic for ordinary
anon pages and THP anon pages, fixing two remaining instances of
CVE-2020-29374 in do_swap_page() and do_huge_pmd_wp_page(): information
can leak from a parent process to a child process via anonymous pages
shared during fork().
This issue, including other related COW issues, has been summarized in [2]:
"1. Observing Memory Modifications of Private Pages From A Child Process
Long story short: process-private memory might not be as private as you
think once you fork(): successive modifications of private memory
regions in the parent process can still be observed by the child
process, for example, by smart use of vmsplice()+munmap().
The core problem is that pinning pages readable in a child process, such
as done via the vmsplice system call, can result in a child process
observing memory modifications done in the parent process the child is
not supposed to observe. [1] contains an excellent summary and [2]
contains further details. This issue was assigned CVE-2020-29374 [9].
For this to trigger, it's required to use a fork() without subsequent
exec(), for example, as used under Android zygote. Without further
details about an application that forks less-privileged child processes,
one cannot really say what's actually affected and what's not -- see the
details section the end of this mail for a short sshd/openssh analysis.
While commit 17839856fd58 ("gup: document and work around "COW can break
either way" issue") fixed this issue and resulted in other problems
(e.g., ptrace on pmem), commit 09854ba94c6a ("mm: do_wp_page()
simplification") re-introduced part of the problem unfortunately.
The original reproducer can be modified quite easily to use THP [3] and
make the issue appear again on upstream kernels. I modified it to use
hugetlb [4] and it triggers as well. The problem is certainly less
severe with hugetlb than with THP; it merely highlights that we still
have plenty of open holes we should be closing/fixing.
Regarding vmsplice(), the only known workaround is to disallow the
vmsplice() system call ... or disable THP and hugetlb. But who knows
what else is affected (RDMA? O_DIRECT?) to achieve the same goal -- in
the end, it's a more generic issue"
This security issue was first reported by Jann Horn on 27 May 2020 and it
currently affects anonymous pages during swapin, anonymous THP and hugetlb.
This series tackles anonymous pages during swapin and anonymous THP:
- do_swap_page() for handling COW on PTEs during swapin directly
- do_huge_pmd_wp_page() for handling COW on PMD-mapped THP during write
faults
With this series, we'll apply the same COW logic we have in do_wp_page()
to all swappable anon pages: don't reuse (map writable) the page in
case there are additional references (page_count() != 1). All users of
reuse_swap_page() are remove, and consequently reuse_swap_page() is
removed.
In general, we're struggling with the following COW-related issues:
(1) "missed COW": we miss to copy on write and reuse the page (map it
writable) although we must copy because there are pending references
from another process to this page. The result is a security issue.
(2) "wrong COW": we copy on write although we wouldn't have to and
shouldn't: if there are valid GUP references, they will become out
of sync with the pages mapped into the page table. We fail to detect
that such a page can be reused safely, especially if never more than
a single process mapped the page. The result is an intra process
memory corruption.
(3) "unnecessary COW": we copy on write although we wouldn't have to:
performance degradation and temporary increases swap+memory
consumption can be the result.
While this series fixes (1) for swappable anon pages, it tries to reduce
reported cases of (3) first as good and easy as possible to limit the
impact when streamlining. The individual patches try to describe in
which cases we will run into (3).
This series certainly makes (2) worse for THP, because a THP will now
get PTE-mapped on write faults if there are additional references, even
if there was only ever a single process involved: once PTE-mapped, we'll
copy each and every subpage and won't reuse any subpage as long as the
underlying compound page wasn't split.
I'm working on an approach to fix (2) and improve (3): PageAnonExclusive
to mark anon pages that are exclusive to a single process, allow GUP
pins only on such exclusive pages, and allow turning exclusive pages
shared (clearing PageAnonExclusive) only if there are no GUP pins. Anon
pages with PageAnonExclusive set never have to be copied during write
faults, but eventually during fork() if they cannot be turned shared.
The improved reuse logic in this series will essentially also be the
logic to reset PageAnonExclusive. This work will certainly take a
while, but I'm planning on sharing details before having code fully
ready.
#1-#5 can be applied independently of the rest. #6-#9 are mostly only
cleanups related to reuse_swap_page().
Notes:
* For now, I'll leave hugetlb code untouched: "unnecessary COW" might
easily break existing setups because hugetlb pages are a scarce resource
and we could just end up having to crash the application when we run out
of hugetlb pages. We have to be very careful and the security aspect with
hugetlb is most certainly less relevant than for unprivileged anon pages.
* Instead of lru_add_drain() we might actually just drain the lru_add list
or even just remove the single page of interest from the lru_add list.
This would require a new helper function, and could be added if the
conditional lru_add_drain() turn out to be a problem.
* I extended the test case already included in [1] to also test for the
newly found do_swap_page() case. I'll send that out separately once/if
this part was merged.
[1] https://lkml.kernel.org/r/20211217113049.23850-1-david@redhat.com
[2] https://lore.kernel.org/r/3ae33b08-d9ef-f846-56fb-645e3b9b4c66@redhat.com
This patch (of 9):
Liang Zhang reported [1] that the current COW logic in do_wp_page() is
sub-optimal when it comes to swap+read fault+write fault of anonymous
pages that have a single user, visible via a performance degradation in
the redis benchmark. Something similar was previously reported [2] by
Nadav with a simple reproducer.
After we put an anon page into the swapcache and unmapped it from a single
process, that process might read that page again and refault it read-only.
If that process then writes to that page, the process is actually the
exclusive user of the page, however, the COW logic in do_co_page() won't
be able to reuse it due to the additional reference from the swapcache.
Let's optimize for pages that have been added to the swapcache but only
have an exclusive user. Try removing the swapcache reference if there is
hope that we're the exclusive user.
We will fail removing the swapcache reference in two scenarios:
(1) There are additional swap entries referencing the page: copying
instead of reusing is the right thing to do.
(2) The page is under writeback: theoretically we might be able to reuse
in some cases, however, we cannot remove the additional reference
and will have to copy.
Note that we'll only try removing the page from the swapcache when it's
highly likely that we'll be the exclusive owner after removing the page
from the swapache. As we're about to map that page writable and redirty
it, that should not affect reclaim but is rather the right thing to do.
Further, we might have additional references from the LRU pagevecs, which
will force us to copy instead of being able to reuse. We'll try handling
such references for some scenarios next. Concurrent writeback cannot be
handled easily and we'll always have to copy.
While at it, remove the superfluous page_mapcount() check: it's
implicitly covered by the page_count() for ordinary anon pages.
[1] https://lkml.kernel.org/r/20220113140318.11117-1-zhangliang5@huawei.com
[2] https://lkml.kernel.org/r/0480D692-D9B2-429A-9A88-9BBA1331AC3A@gmail.com
Link: https://lkml.kernel.org/r/20220131162940.210846-2-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reported-by: Liang Zhang <zhangliang5@huawei.com>
Reported-by: Nadav Amit <nadav.amit@gmail.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Jann Horn <jannh@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Don Dutile <ddutile@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
It's only used inside the huge_memory.c now. Don't export it and make
it static. We can thus reduce the size of huge_memory.o a bit.
Without this patch:
text data bss dec hex filename
32319 2965 4 35288 89d8 mm/huge_memory.o
With this patch:
text data bss dec hex filename
32042 2957 4 35003 88bb mm/huge_memory.o
Link: https://lkml.kernel.org/r/20220302082145.12028-1-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
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With MADV_DONTNEED support added to hugetlb mappings, mremap testing can
also be enabled for hugetlb.
Modify the tests to use madvise MADV_DONTNEED and MADV_REMOVE instead of
fallocate hole puch for releasing hugetlb pages.
Link: https://lkml.kernel.org/r/20220215002348.128823-4-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Axel Rasmussen <axelrasmussen@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Peter Xu <peterx@redhat.com>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Now that MADV_DONTNEED support for hugetlb is enabled, add corresponding
tests. MADV_REMOVE has been enabled for some time, but no tests exist so
add them as well.
Link: https://lkml.kernel.org/r/20220215002348.128823-3-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Patch series "Add hugetlb MADV_DONTNEED support", v3.
Userfaultfd selftests for hugetlb does not perform UFFD_EVENT_REMAP
testing. However, mremap support was recently added in commit
550a7d60bd5e ("mm, hugepages: add mremap() support for hugepage backed
vma"). While attempting to enable mremap support in the test, it was
discovered that the mremap test indirectly depends on MADV_DONTNEED.
madvise does not allow MADV_DONTNEED for hugetlb mappings. However, that
is primarily due to the check in can_madv_lru_vma(). By simply removing
the check and adding huge page alignment, MADV_DONTNEED can be made to
work for hugetlb mappings.
Do note that there is no compelling use case for adding this support.
This was discussed in the RFC [1]. However, adding support makes sense as
it is fairly trivial and brings hugetlb functionality more in line with
'normal' memory.
After enabling support, add selftest for MADV_DONTNEED as well as
MADV_REMOVE. Then update userfaultfd selftest.
If new functionality is accepted, then madvise man page will be updated to
indicate hugetlb is supported. It will also be updated to clarify what
happens to the passed length argument.
This patch (of 3):
MADV_DONTNEED is currently disabled for hugetlb mappings. This certainly
makes sense in shared file mappings as the pagecache maintains a reference
to the page and it will never be freed. However, it could be useful to
unmap and free pages in private mappings. In addition, userfaultfd minor
fault users may be able to simplify code by using MADV_DONTNEED.
The primary thing preventing MADV_DONTNEED from working on hugetlb
mappings is a check in can_madv_lru_vma(). To allow support for hugetlb
mappings create and use a new routine madvise_dontneed_free_valid_vma()
that allows hugetlb mappings in this specific case.
For normal mappings, madvise requires the start address be PAGE aligned
and rounds up length to the next multiple of PAGE_SIZE. Do similarly for
hugetlb mappings: require start address be huge page size aligned and
round up length to the next multiple of huge page size. Use the new
madvise_dontneed_free_valid_vma routine to check alignment and round up
length/end. zap_page_range requires this alignment for hugetlb vmas
otherwise we will hit BUGs.
Link: https://lkml.kernel.org/r/20220215002348.128823-1-mike.kravetz@oracle.com
Link: https://lkml.kernel.org/r/20220215002348.128823-2-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: David Hildenbrand <david@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: Mike Rapoport <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
If LOCKDEP detects a bug while KASAN is printing a report and if
panic_on_warn is set, KASAN will not be able to finish. Disable LOCKDEP
while KASAN is printing a report.
See https://bugzilla.kernel.org/show_bug.cgi?id=202115 for an example
of the issue.
Link: https://lkml.kernel.org/r/c48a2a3288200b07e1788b77365c2f02784cfeb4.1646237226.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
- Move kasan_save_enable/restore_multi_shot() declarations to
mm/kasan/kasan.h, as there is no need for them to be visible outside
of KASAN implementation.
- Only define and export these functions when KASAN tests are enabled.
- Move their definitions closer to other test-related code in report.c.
Link: https://lkml.kernel.org/r/6ba637333b78447f027d775f2d55ab1a40f63c99.1646237226.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Move print_error_description()'s, report_suppressed()'s, and
report_enabled()'s definitions to improve the logical order of function
definitions in report.c.
No functional changes.
Link: https://lkml.kernel.org/r/82aa926c411e00e76e97e645a551ede9ed0c5e79.1646237226.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Currently, only kasan_report() checks the KASAN_BIT_REPORTED and
KASAN_BIT_MULTI_SHOT flags.
Make other reporting routines check these flags as well.
Also add explanatory comments.
Note that the current->kasan_depth check is split out into
report_suppressed() and only called for kasan_report().
Link: https://lkml.kernel.org/r/715e346b10b398e29ba1b425299dcd79e29d58ce.1646237226.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Add a comment explaining why kasan_report() is the only reporting function
that uses user_access_save/restore().
Link: https://lkml.kernel.org/r/1201ca3c2be42c7bd077c53d2e46f4a51dd1476a.1646237226.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Rename kasan_access_info to kasan_report_info, as the latter name better
reflects the struct's purpose.
Link: https://lkml.kernel.org/r/158a4219a5d356901d017352558c989533a0782c.1646237226.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Place kasan_report_async() next to the other main reporting routines.
Also simplify printed information.
Link: https://lkml.kernel.org/r/52d942ef3ffd29bdfa225bbe8e327bc5bda7ab09.1646237226.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Call print_report() in kasan_report_invalid_free() instead of calling
printing functions directly. Compared to the existing implementation of
kasan_report_invalid_free(), print_report() makes sure that the buggy
address has metadata before printing it.
The change requires adding a report type field into kasan_access_info and
using it accordingly.
kasan_report_async() is left as is, as using print_report() will only
complicate the code.
Link: https://lkml.kernel.org/r/9ea6f0604c5d2e1fb28d93dc6c44232c1f8017fe.1646237226.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Merge __kasan_report() into kasan_report(). The code is simple enough to
be readable without the __kasan_report() helper.
Link: https://lkml.kernel.org/r/c8a125497ef82f7042b3795918dffb81a85a878e.1646237226.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Restructure kasan_report() to make reviewing the subsequent patches
easier.
Link: https://lkml.kernel.org/r/ca28042889858b8cc4724d3d4378387f90d7a59d.1646237226.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Move the addr_has_metadata() check into kasan_find_first_bad_addr().
Link: https://lkml.kernel.org/r/a49576f7a23283d786ba61579cb0c5057e8f0b9b.1646237226.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Split out the part of __kasan_report() that prints things into
print_report(). One of the subsequent patches makes another error handler
use print_report() as well.
Includes lower-level changes:
- Allow addr_has_metadata() accepting a tagged address.
- Drop the const qualifier from the fields of kasan_access_info to
avoid excessive type casts.
- Change the type of the address argument of __kasan_report() and
end_report() to void * to reduce the number of type casts.
Link: https://lkml.kernel.org/r/9be3ed99dd24b9c4e1c4a848b69a0c6ecefd845e.1646237226.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Move the disable_trace_on_warning() call, which enables the
/proc/sys/kernel/traceoff_on_warning interface for KASAN bugs, to
start_report(), so that it functions for all types of KASAN reports.
Link: https://lkml.kernel.org/r/7c066c5de26234ad2cebdd931adfe437f8a95d58.1646237226.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Instead of duplicating calls to update_kunit_status() in every error
report routine, call it once in start_report(). Pass the sync flag as an
additional argument to start_report().
Link: https://lkml.kernel.org/r/cae5c845a0b6f3c867014e53737cdac56b11edc7.1646237226.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Check the more specific CONFIG_KASAN_KUNIT_TEST config option when
defining things related to KUnit-compatible KASAN tests instead of
CONFIG_KUNIT.
Also put the kunit_kasan_status definition next to the definitons of other
KASAN-related structs.
Link: https://lkml.kernel.org/r/223592d38d2a601a160a3b2b3d5a9f9090350e62.1646237226.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
- Rename kasan_update_kunit_status() to update_kunit_status() (the
function is static).
- Move the IS_ENABLED(CONFIG_KUNIT) to the function's definition
instead of duplicating it at call sites.
- Obtain and check current->kunit_test within the function.
Link: https://lkml.kernel.org/r/dac26d811ae31856c3d7666de0b108a3735d962d.1646237226.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Currently, end_report() does not call trace_error_report_end() for bugs
detected in either async or asymm mode (when kasan_async_fault_possible()
returns true), as the address of the bad access might be unknown.
However, for asymm mode, the address is known for faults triggered by read
operations.
Instead of using kasan_async_fault_possible(), simply check that the addr
is not NULL when calling trace_error_report_end().
Link: https://lkml.kernel.org/r/1c8ce43f97300300e62c941181afa2eb738965c5.1646237226.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
