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2022-11-11KVM: arm64: Unmap 'kvm_arm_hyp_percpu_base' from the hostQuentin Perret4-10/+8
When pKVM is enabled, the hypervisor at EL2 does not trust the host at EL1 and must therefore prevent it from having unrestricted access to internal hypervisor state. The 'kvm_arm_hyp_percpu_base' array holds the offsets for hypervisor per-cpu allocations, so move this this into the nVHE code where it cannot be modified by the untrusted host at EL1. Tested-by: Vincent Donnefort <vdonnefort@google.com> Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221110190259.26861-22-will@kernel.org
2022-11-11KVM: arm64: Return guest memory from EL2 via dedicated teardown memcacheQuentin Perret5-44/+40
Rather than relying on the host to free the previously-donated pKVM hypervisor VM pages explicitly on teardown, introduce a dedicated teardown memcache which allows the host to reclaim guest memory resources without having to keep track of all of the allocations made by the pKVM hypervisor at EL2. Tested-by: Vincent Donnefort <vdonnefort@google.com> Co-developed-by: Fuad Tabba <tabba@google.com> Signed-off-by: Fuad Tabba <tabba@google.com> Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Will Deacon <will@kernel.org> [maz: dropped __maybe_unused from unmap_donated_memory_noclear()] Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221110190259.26861-21-will@kernel.org
2022-11-11KVM: arm64: Instantiate guest stage-2 page-tables at EL2Quentin Perret3-3/+132
Extend the initialisation of guest data structures within the pKVM hypervisor at EL2 so that we instantiate a memory pool and a full 'struct kvm_s2_mmu' structure for each VM, with a stage-2 page-table entirely independent from the one managed by the host at EL1. The 'struct kvm_pgtable_mm_ops' used by the page-table code is populated with a set of callbacks that can manage guest pages in the hypervisor without any direct intervention from the host, allocating page-table pages from the provided pool and returning these to the host on VM teardown. To keep things simple, the stage-2 MMU for the guest is configured identically to the host stage-2 in the VTCR register and so the IPA size of the guest must match the PA size of the host. For now, the new page-table is unused as there is no way for the host to map anything into it. Yet. Tested-by: Vincent Donnefort <vdonnefort@google.com> Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221110190259.26861-20-will@kernel.org
2022-11-11KVM: arm64: Consolidate stage-2 initialisation into a single functionQuentin Perret6-48/+41
The initialisation of guest stage-2 page-tables is currently split across two functions: kvm_init_stage2_mmu() and kvm_arm_setup_stage2(). That is presumably for historical reasons as kvm_arm_setup_stage2() originates from the (now defunct) KVM port for 32-bit Arm. Simplify this code path by merging both functions into one, taking care to map the 'struct kvm' into the hypervisor stage-1 early on in order to simplify the failure path. Tested-by: Vincent Donnefort <vdonnefort@google.com> Co-developed-by: Fuad Tabba <tabba@google.com> Signed-off-by: Fuad Tabba <tabba@google.com> Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221110190259.26861-19-will@kernel.org
2022-11-11KVM: arm64: Add generic hyp_memcache helpersQuentin Perret4-0/+118
The host at EL1 and the pKVM hypervisor at EL2 will soon need to exchange memory pages dynamically for creating and destroying VM state. Indeed, the hypervisor will rely on the host to donate memory pages it can use to create guest stage-2 page-tables and to store VM and vCPU metadata. In order to ease this process, introduce a 'struct hyp_memcache' which is essentially a linked list of available pages, indexed by physical addresses so that it can be passed meaningfully between the different virtual address spaces configured at EL1 and EL2. Tested-by: Vincent Donnefort <vdonnefort@google.com> Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221110190259.26861-18-will@kernel.org
2022-11-11KVM: arm64: Provide I-cache invalidation by virtual address at EL2Will Deacon5-3/+16
In preparation for handling cache maintenance of guest pages from within the pKVM hypervisor at EL2, introduce an EL2 copy of icache_inval_pou() which will later be plumbed into the stage-2 page-table cache maintenance callbacks, ensuring that the initial contents of pages mapped as executable into the guest stage-2 page-table is visible to the instruction fetcher. Tested-by: Vincent Donnefort <vdonnefort@google.com> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221110190259.26861-17-will@kernel.org
2022-11-11KVM: arm64: Initialise hypervisor copies of host symbols unconditionallyWill Deacon1-6/+9
The nVHE object at EL2 maintains its own copies of some host variables so that, when pKVM is enabled, the host cannot directly modify the hypervisor state. When running in normal nVHE mode, however, these variables are still mirrored at EL2 but are not initialised. Initialise the hypervisor symbols from the host copies regardless of pKVM, ensuring that any reference to this data at EL2 with normal nVHE will return a sensibly initialised value. Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Tested-by: Vincent Donnefort <vdonnefort@google.com> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221110190259.26861-16-will@kernel.org
2022-11-11KVM: arm64: Add per-cpu fixmap infrastructure at EL2Quentin Perret7-13/+128
Mapping pages in a guest page-table from within the pKVM hypervisor at EL2 may require cache maintenance to ensure that the initialised page contents is visible even to non-cacheable (e.g. MMU-off) accesses from the guest. In preparation for performing this maintenance at EL2, introduce a per-vCPU fixmap which allows the pKVM hypervisor to map guest pages temporarily into its stage-1 page-table for the purposes of cache maintenance and, in future, poisoning on the reclaim path. The use of a fixmap avoids the need for memory allocation or locking on the map() path. Tested-by: Vincent Donnefort <vdonnefort@google.com> Signed-off-by: Quentin Perret <qperret@google.com> Co-developed-by: Will Deacon <will@kernel.org> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221110190259.26861-15-will@kernel.org
2022-11-11KVM: arm64: Instantiate pKVM hypervisor VM and vCPU structures from EL1Fuad Tabba6-6/+182
With the pKVM hypervisor at EL2 now offering hypercalls to the host for creating and destroying VM and vCPU structures, plumb these in to the existing arm64 KVM backend to ensure that the hypervisor data structures are allocated and initialised on first vCPU run for a pKVM guest. In the host, 'struct kvm_protected_vm' is introduced to hold the handle of the pKVM VM instance as well as to track references to the memory donated to the hypervisor so that it can be freed back to the host allocator following VM teardown. The stage-2 page-table, hypervisor VM and vCPU structures are allocated separately so as to avoid the need for a large physically-contiguous allocation in the host at run-time. Tested-by: Vincent Donnefort <vdonnefort@google.com> Signed-off-by: Fuad Tabba <tabba@google.com> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221110190259.26861-14-will@kernel.org
2022-11-11KVM: arm64: Add infrastructure to create and track pKVM instances at EL2Fuad Tabba12-0/+531
Introduce a global table (and lock) to track pKVM instances at EL2, and provide hypercalls that can be used by the untrusted host to create and destroy pKVM VMs and their vCPUs. pKVM VM/vCPU state is directly accessible only by the trusted hypervisor (EL2). Each pKVM VM is directly associated with an untrusted host KVM instance, and is referenced by the host using an opaque handle. Future patches will provide hypercalls to allow the host to initialize/set/get pKVM VM/vCPU state using the opaque handle. Tested-by: Vincent Donnefort <vdonnefort@google.com> Signed-off-by: Fuad Tabba <tabba@google.com> Co-developed-by: Will Deacon <will@kernel.org> Signed-off-by: Will Deacon <will@kernel.org> [maz: silence warning on unmap_donated_memory_noclear()] Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221110190259.26861-13-will@kernel.org
2022-11-11KVM: arm64: Rename 'host_kvm' to 'host_mmu'Will Deacon2-26/+26
In preparation for introducing VM and vCPU state at EL2, rename the existing 'struct host_kvm' and its singleton 'host_kvm' instance to 'host_mmu' so as to avoid confusion between the structure tracking the host stage-2 MMU state and the host instance of a 'struct kvm' for a protected guest. Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Tested-by: Vincent Donnefort <vdonnefort@google.com> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221110190259.26861-12-will@kernel.org
2022-11-11KVM: arm64: Add hyp_spinlock_t static initializerFuad Tabba1-1/+9
Introduce a static initializer macro for 'hyp_spinlock_t' so that it is straightforward to instantiate global locks at EL2. This will be later utilised for locking the VM table in the hypervisor. Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Tested-by: Vincent Donnefort <vdonnefort@google.com> Signed-off-by: Fuad Tabba <tabba@google.com> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221110190259.26861-11-will@kernel.org
2022-11-11KVM: arm64: Include asm/kvm_mmu.h in nvhe/mem_protect.hWill Deacon1-0/+1
nvhe/mem_protect.h refers to __load_stage2() in the definition of __load_host_stage2() but doesn't include the relevant header. Include asm/kvm_mmu.h in nvhe/mem_protect.h so that users of the latter don't have to do this themselves. Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Tested-by: Vincent Donnefort <vdonnefort@google.com> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221110190259.26861-10-will@kernel.org
2022-11-11KVM: arm64: Add helpers to pin memory shared with the hypervisor at EL2Quentin Perret3-1/+57
Add helpers allowing the hypervisor to check whether a range of pages are currently shared by the host, and 'pin' them if so by blocking host unshare operations until the memory has been unpinned. This will allow the hypervisor to take references on host-provided data-structures (e.g. 'struct kvm') with the guarantee that these pages will remain in a stable state until the hypervisor decides to release them, for example during guest teardown. Tested-by: Vincent Donnefort <vdonnefort@google.com> Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221110190259.26861-9-will@kernel.org
2022-11-11KVM: arm64: Prevent the donation of no-map pagesQuentin Perret1-6/+16
Memory regions marked as "no-map" in the host device-tree routinely include TrustZone carev-outs and DMA pools. Although donating such pages to the hypervisor may not breach confidentiality, it could be used to corrupt its state in uncontrollable ways. To prevent this, let's block host-initiated memory transitions targeting "no-map" pages altogether in nVHE protected mode as there should be no valid reason to do this in current operation. Thankfully, the pKVM EL2 hypervisor has a full copy of the host's list of memblock regions, so we can easily check for the presence of the MEMBLOCK_NOMAP flag on a region containing pages being donated from the host. Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Tested-by: Vincent Donnefort <vdonnefort@google.com> Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221110190259.26861-8-will@kernel.org
2022-11-11KVM: arm64: Implement do_donate() helper for donating memoryWill Deacon2-0/+241
Transferring ownership information of a memory region from one component to another can be achieved using a "donate" operation, which results in the previous owner losing access to the underlying pages entirely and the new owner having exclusive access to the page. Implement a do_donate() helper, along the same lines as do_{un,}share, and provide this functionality for the host-{to,from}-hyp cases as this will later be used to donate/reclaim memory pages to store VM metadata at EL2. In a similar manner to the sharing transitions, permission checks are performed by the hypervisor to ensure that the component initiating the transition really is the owner of the page and also that the completer does not currently have a page mapped at the target address. Tested-by: Vincent Donnefort <vdonnefort@google.com> Co-developed-by: Quentin Perret <qperret@google.com> Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221110190259.26861-7-will@kernel.org
2022-11-11KVM: arm64: Unify identifiers used to distinguish host and hypervisorWill Deacon3-10/+6
The 'pkvm_component_id' enum type provides constants to refer to the host and the hypervisor, yet this information is duplicated by the 'pkvm_hyp_id' constant. Remove the definition of 'pkvm_hyp_id' and move the 'pkvm_component_id' type definition to 'mem_protect.h' so that it can be used outside of the memory protection code, for example when initialising the owner for hypervisor-owned pages. Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Tested-by: Vincent Donnefort <vdonnefort@google.com> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221110190259.26861-6-will@kernel.org
2022-11-11KVM: arm64: Fix-up hyp stage-1 refcounts for all pages mapped at EL2Quentin Perret1-19/+43
In order to allow unmapping arbitrary memory pages from the hypervisor stage-1 page-table, fix-up the initial refcount for pages that have been mapped before the 'vmemmap' array was up and running so that it accurately accounts for all existing hypervisor mappings. This is achieved by traversing the entire hypervisor stage-1 page-table during initialisation of EL2 and updating the corresponding 'struct hyp_page' for each valid mapping. Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Tested-by: Vincent Donnefort <vdonnefort@google.com> Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221110190259.26861-5-will@kernel.org
2022-11-11KVM: arm64: Back the hypervisor 'struct hyp_page' array for all memoryQuentin Perret6-40/+60
The EL2 'vmemmap' array in nVHE Protected mode is currently very sparse: only memory pages owned by the hypervisor itself have a matching 'struct hyp_page'. However, as the size of this struct has been reduced significantly since its introduction, it appears that we can now afford to back the vmemmap for all of memory. Having an easily accessible 'struct hyp_page' for every physical page in memory provides the hypervisor with a simple mechanism to store metadata (e.g. a refcount) that wouldn't otherwise fit in the very limited number of software bits available in the host stage-2 page-table entries. This will be used in subsequent patches when pinning host memory pages for use by the hypervisor at EL2. Tested-by: Vincent Donnefort <vdonnefort@google.com> Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221110190259.26861-4-will@kernel.org
2022-11-11KVM: arm64: Allow attaching of non-coalescable pages to a hyp poolQuentin Perret1-0/+6
All the contiguous pages used to initialize a 'struct hyp_pool' are considered coalescable, which means that the hyp page allocator will actively try to merge them with their buddies on the hyp_put_page() path. However, using hyp_put_page() on a page that is not part of the inital memory range given to a hyp_pool() is currently unsupported. In order to allow dynamically extending hyp pools at run-time, add a check to __hyp_attach_page() to allow inserting 'external' pages into the free-list of order 0. This will be necessary to allow lazy donation of pages from the host to the hypervisor when allocating guest stage-2 page-table pages at EL2. Tested-by: Vincent Donnefort <vdonnefort@google.com> Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221110190259.26861-3-will@kernel.org
2022-11-11KVM: arm64: Move hyp refcount manipulation helpers to common header fileQuentin Perret2-19/+22
We will soon need to manipulate 'struct hyp_page' refcounts from outside page_alloc.c, so move the helpers to a common header file to allow them to be reused easily. Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Reviewed-by: Oliver Upton <oliver.upton@linux.dev> Tested-by: Vincent Donnefort <vdonnefort@google.com> Signed-off-by: Quentin Perret <qperret@google.com> Signed-off-by: Will Deacon <will@kernel.org> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20221110190259.26861-2-will@kernel.org
2022-10-30Linux 6.1-rc3v6.1-rc3Linus Torvalds1-1/+1
2022-10-30Merge tag 'fbdev-for-6.1-rc3' of ↵Linus Torvalds11-38/+47
git://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev Pull fbdev fixes from Helge Deller: "A use-after-free bugfix in the smscufx driver and various minor error path fixes, smaller build fixes, sysfs fixes and typos in comments in the stifb, sisfb, da8xxfb, xilinxfb, sm501fb, gbefb and cyber2000fb drivers" * tag 'fbdev-for-6.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev: fbdev: cyber2000fb: fix missing pci_disable_device() fbdev: sisfb: use explicitly signed char fbdev: smscufx: Fix several use-after-free bugs fbdev: xilinxfb: Make xilinxfb_release() return void fbdev: sisfb: fix repeated word in comment fbdev: gbefb: Convert sysfs snprintf to sysfs_emit fbdev: sm501fb: Convert sysfs snprintf to sysfs_emit fbdev: stifb: Fall back to cfb_fillrect() on 32-bit HCRX cards fbdev: da8xx-fb: Fix error handling in .remove() fbdev: MIPS supports iomem addresses
2022-10-30Merge tag 'char-misc-6.1-rc3' of ↵Linus Torvalds17-91/+175
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc Pull char/misc fixes from Greg KH: "Some small driver fixes for 6.1-rc3. They include: - iio driver bugfixes - counter driver bugfixes - coresight bugfixes, including a revert and then a second fix to get it right. All of these have been in linux-next with no reported problems" * tag 'char-misc-6.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (21 commits) misc: sgi-gru: use explicitly signed char coresight: cti: Fix hang in cti_disable_hw() Revert "coresight: cti: Fix hang in cti_disable_hw()" counter: 104-quad-8: Fix race getting function mode and direction counter: microchip-tcb-capture: Handle Signal1 read and Synapse coresight: cti: Fix hang in cti_disable_hw() coresight: Fix possible deadlock with lock dependency counter: ti-ecap-capture: fix IS_ERR() vs NULL check counter: Reduce DEFINE_COUNTER_ARRAY_POLARITY() to defining counter_array iio: bmc150-accel-core: Fix unsafe buffer attributes iio: adxl367: Fix unsafe buffer attributes iio: adxl372: Fix unsafe buffer attributes iio: at91-sama5d2_adc: Fix unsafe buffer attributes iio: temperature: ltc2983: allocate iio channels once tools: iio: iio_utils: fix digit calculation iio: adc: stm32-adc: fix channel sampling time init iio: adc: mcp3911: mask out device ID in debug prints iio: adc: mcp3911: use correct id bits iio: adc: mcp3911: return proper error code on failure to allocate trigger iio: adc: mcp3911: fix sizeof() vs ARRAY_SIZE() bug ...
2022-10-30Merge tag 'usb-6.1-rc3' of ↵Linus Torvalds15-133/+169
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb Pull USB fixes from Greg KH: "A few small USB fixes for 6.1-rc3. Include in here are: - MAINTAINERS update, including a big one for the USB gadget subsystem. Many thanks to Felipe for all of the years of hard work he has done on this codebase, it was greatly appreciated. - dwc3 driver fixes for reported problems. - xhci driver fixes for reported problems. - typec driver fixes for minor issues - uvc gadget driver change, and then revert as it wasn't relevant for 6.1-final, as it is a new feature and people are still reviewing and modifying it. All of these have been in the linux-next tree with no reported issues" * tag 'usb-6.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: usb: dwc3: gadget: Don't set IMI for no_interrupt usb: dwc3: gadget: Stop processing more requests on IMI Revert "usb: gadget: uvc: limit isoc_sg to super speed gadgets" xhci: Remove device endpoints from bandwidth list when freeing the device xhci-pci: Set runtime PM as default policy on all xHC 1.2 or later devices xhci: Add quirk to reset host back to default state at shutdown usb: xhci: add XHCI_SPURIOUS_SUCCESS to ASM1042 despite being a V0.96 controller usb: dwc3: st: Rely on child's compatible instead of name usb: gadget: uvc: limit isoc_sg to super speed gadgets usb: bdc: change state when port disconnected usb: typec: ucsi: acpi: Implement resume callback usb: typec: ucsi: Check the connection on resume usb: gadget: aspeed: Fix probe regression usb: gadget: uvc: fix sg handling during video encode usb: gadget: uvc: fix sg handling in error case usb: gadget: uvc: fix dropped frame after missed isoc usb: dwc3: gadget: Don't delay End Transfer on delayed_status usb: dwc3: Don't switch OTG -> peripheral if extcon is present MAINTAINERS: Update maintainers for broadcom USB MAINTAINERS: move USB gadget and phy entries under the main USB entry
2022-10-30Merge tag 'gpio-fixes-for-v6.1-rc3' of ↵Linus Torvalds2-18/+46
git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux Pull gpio fixes from Bartosz Golaszewski: - convert gpio-tegra to using an immutable irqchip - MAINTAINERS update * tag 'gpio-fixes-for-v6.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux: MAINTAINERS: Change myself to a maintainer gpio: tegra: Convert to immutable irq chip
2022-10-30Merge tag 'perf_urgent_for_v6.1_rc3' of ↵Linus Torvalds4-2/+7
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf fixes from Borislav Petkov: - Rename a perf memory level event define to denote it is of CXL type - Add Alder and Raptor Lakes support to RAPL - Make sure raw sample data is output with tracepoints * tag 'perf_urgent_for_v6.1_rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf/mem: Rename PERF_MEM_LVLNUM_EXTN_MEM to PERF_MEM_LVLNUM_CXL perf/x86/rapl: Add support for Intel Raptor Lake perf/x86/rapl: Add support for Intel AlderLake-N perf: Fix missing raw data on tracepoint events
2022-10-30Merge tag 'loongarch-fixes-6.1-1' of ↵Linus Torvalds7-36/+34
git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson Pull LoongArch fixes from Huacai Chen: "Remove unused kernel stack padding, fix some build errors/warnings and two bugs in laptop platform driver" * tag 'loongarch-fixes-6.1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson: platform/loongarch: laptop: Fix possible UAF and simplify generic_acpi_laptop_init() platform/loongarch: laptop: Adjust resume order for loongson_hotkey_resume() LoongArch: BPF: Avoid declare variables in switch-case LoongArch: Use flexible-array member instead of zero-length array LoongArch: Remove unused kernel stack padding
2022-10-30Merge tag '6.1-rc2-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6Linus Torvalds2-3/+11
Pull cifs fixes from Steve French: - use after free fix for reconnect race - two memory leak fixes * tag '6.1-rc2-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6: cifs: fix use-after-free caused by invalid pointer `hostname` cifs: Fix pages leak when writedata alloc failed in cifs_write_from_iter() cifs: Fix pages array leak when writedata alloc failed in cifs_writedata_alloc()
2022-10-29Merge tag 'random-6.1-rc3-for-linus' of ↵Linus Torvalds1-2/+2
git://git.kernel.org/pub/scm/linux/kernel/git/crng/random Pull random number generator fix from Jason Donenfeld: "One fix from Jean-Philippe Brucker, addressing a regression in which early boot code on ARM64 would use the non-_early variant of the arch_get_random family of functions, resulting in the architectural random number generator appearing unavailable during that early phase of boot. The fix simply changes arch_get_random*() to arch_get_random*_early(). This distinction between these two functions is a bit of an old wart I'm not a fan of, and for 6.2 I'll see if I can make obsolete the _early variant, so that one function does the right thing in all contexts without overhead" * tag 'random-6.1-rc3-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random: random: use arch_get_random*_early() in random_init()
2022-10-29Merge tag 'scsi-fixes' of ↵Linus Torvalds14-55/+96
git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi Pull SCSI fixes from James Bottomley: "Varions small fixes, all in drivers. Some of these arrived during the merge window and got held over to make sure of testing on the -rc tree. The biggest change is for standards conformance in the target driver, closely followed by a set of bug fixes in megaraid_sas" * tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (21 commits) scsi: ufs: core: Fix typo in comment scsi: mpi3mr: Select CONFIG_SCSI_SAS_ATTRS scsi: ufs: core: Fix typo for register name in comments scsi: pm80xx: Display proc_name in sysfs scsi: ufs: core: Fix the error log in ufshcd_query_flag_retry() scsi: ufs: core: Remove unneeded casts from void * scsi: lpfc: Fix spelling mistake "unsolicted" -> "unsolicited" scsi: qla2xxx: Use transport-defined speed mask for supported_speeds scsi: target: iblock: Fold iblock_emulate_read_cap_with_block_size() into iblock_get_blocks() scsi: qla2xxx: Fix serialization of DCBX TLV data request scsi: ufs: qcom: Remove redundant dev_err() call scsi: megaraid_sas: Move megasas_dbg_lvl init to megasas_init() scsi: megaraid_sas: Remove unnecessary memset() scsi: megaraid_sas: Simplify megasas_update_device_list scsi: megaraid_sas: Correct an error message scsi: megaraid_sas: Correct value passed to scsi_device_lookup() scsi: target: core: UA on all LUNs after reset scsi: target: core: New key must be used for moved PR scsi: target: core: Abort all preempted regs if requested scsi: target: core: Fix memory leak in preempt_and_abort ...
2022-10-29Merge tag 'block-6.1-2022-10-28' of git://git.kernel.dk/linuxLinus Torvalds6-9/+31
Pull block fixes from Jens Axboe: - NVMe pull request via Christoph: - make the multipath dma alignment match the non-multipath one (Keith Busch) - fix a bogus use of sg_init_marker() (Nam Cao) - fix circulr locking in nvme-tcp (Sagi Grimberg) - Initialization fix for requests allocated via the special hw queue allocator (John) - Fix for a regression added in this release with the batched completions of end_io backed requests (Ming) - Error handling leak fix for rbd (Yang) - Error handling leak fix for add_disk() failure (Yu) * tag 'block-6.1-2022-10-28' of git://git.kernel.dk/linux: blk-mq: Properly init requests from blk_mq_alloc_request_hctx() blk-mq: don't add non-pt request with ->end_io to batch rbd: fix possible memory leak in rbd_sysfs_init() nvme-multipath: set queue dma alignment to 3 nvme-tcp: fix possible circular locking when deleting a controller under memory pressure nvme-tcp: replace sg_init_marker() with sg_init_table() block: fix memory leak for elevator on add_disk failure
2022-10-29Merge tag 'io_uring-6.1-2022-10-28' of git://git.kernel.dk/linuxLinus Torvalds2-8/+16
Pull io_uring fix from Jens Axboe: "Just a fix for a locking regression introduced with the deferred task_work running from this merge window" * tag 'io_uring-6.1-2022-10-28' of git://git.kernel.dk/linux: io_uring: unlock if __io_run_local_work locked inside io_uring: use io_run_local_work_locked helper
2022-10-29Merge tag 'mm-hotfixes-stable-2022-10-28' of ↵Linus Torvalds28-68/+196
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull misc hotfixes from Andrew Morton: "Eight fix pre-6.0 bugs and the remainder address issues which were introduced in the 6.1-rc merge cycle, or address issues which aren't considered sufficiently serious to warrant a -stable backport" * tag 'mm-hotfixes-stable-2022-10-28' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (23 commits) mm: multi-gen LRU: move lru_gen_add_mm() out of IRQ-off region lib: maple_tree: remove unneeded initialization in mtree_range_walk() mmap: fix remap_file_pages() regression mm/shmem: ensure proper fallback if page faults mm/userfaultfd: replace kmap/kmap_atomic() with kmap_local_page() x86: fortify: kmsan: fix KMSAN fortify builds x86: asm: make sure __put_user_size() evaluates pointer once Kconfig.debug: disable CONFIG_FRAME_WARN for KMSAN by default x86/purgatory: disable KMSAN instrumentation mm: kmsan: export kmsan_copy_page_meta() mm: migrate: fix return value if all subpages of THPs are migrated successfully mm/uffd: fix vma check on userfault for wp mm: prep_compound_tail() clear page->private mm,madvise,hugetlb: fix unexpected data loss with MADV_DONTNEED on hugetlbfs mm/page_isolation: fix clang deadcode warning fs/ext4/super.c: remove unused `deprecated_msg' ipc/msg.c: fix percpu_counter use after free memory tier, sysfs: rename attribute "nodes" to "nodelist" MAINTAINERS: git://github.com -> https://github.com for nilfs2 mm/kmemleak: prevent soft lockup in kmemleak_scan()'s object iteration loops ...
2022-10-29Merge tag 'powerpc-6.1-3' of ↵Linus Torvalds13-45/+212
git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux Pull powerpc fixes from Michael Ellerman: - Fix a case of rescheduling with user access unlocked, when preempt is enabled. - A follow-up fix for a recent fix, which could lead to IRQ state assertions firing incorrectly. - Two fixes for lockdep warnings seen when using kfence with the Hash MMU. - Two fixes for preempt warnings seen when using the Hash MMU. - Two fixes for the VAS coprocessor mechanism used on pseries. - Prevent building some of our older KVM backends when CONTEXT_TRACKING_USER is enabled, as it's known to cause crashes. - A couple of fixes for issues seen with PMU NMIs. Thanks to Nicholas Piggin, Guenter Roeck, Frederic Barrat Haren Myneni, Sachin Sant, and Samuel Holland. * tag 'powerpc-6.1-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: powerpc/64s/interrupt: Fix clear of PACA_IRQS_HARD_DIS when returning to soft-masked context powerpc/64s/interrupt: Perf NMI should not take normal exit path powerpc/64/interrupt: Prevent NMI PMI causing a dangerous warning KVM: PPC: BookS PR-KVM and BookE do not support context tracking powerpc: Fix reschedule bug in KUAP-unlocked user copy powerpc/64s: Fix hash__change_memory_range preemption warning powerpc/64s: Disable preemption in hash lazy mmu mode powerpc/64s: make linear_map_hash_lock a raw spinlock powerpc/64s: make HPTE lock and native_tlbie_lock irq-safe powerpc/64s: Add lockdep for HPTE lock powerpc/pseries: Use lparcfg to reconfig VAS windows for DLPAR CPU powerpc/pseries/vas: Add VAS IRQ primary handler
2022-10-29platform/loongarch: laptop: Fix possible UAF and simplify ↵Yang Yingliang1-3/+7
generic_acpi_laptop_init() Currently the return value of 'sub_driver->init' is not checked. If sparse_keymap_setup() called in the init function fails, 'generic_ inputdev' is freed, then it will lead a UAF when using it in generic_ acpi_laptop_init(). Fix it by checking the return value and setting generic_inputdev to NULL after free, so as to avoid double free it. The error code in generic_subdriver_init() is always negative, so the return of generic_subdriver_init() can be simplified. Fixes: 6246ed09111f ("LoongArch: Add ACPI-based generic laptop driver") Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-10-29platform/loongarch: laptop: Adjust resume order for loongson_hotkey_resume()Huacai Chen1-7/+7
Some laptops don't support SW_LID, but still have backlight control, move backlight resuming before SW_LID event handling so as to avoid backlight mistake due to early return. Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-10-29LoongArch: BPF: Avoid declare variables in switch-caseHuacai Chen1-18/+13
Not all compilers support declare variables in switch-case, so move declarations to the beginning of a function. Otherwise we may get such build errors: arch/loongarch/net/bpf_jit.c: In function ‘emit_atomic’: arch/loongarch/net/bpf_jit.c:362:3: error: a label can only be part of a statement and a declaration is not a statement u8 r0 = regmap[BPF_REG_0]; ^~ arch/loongarch/net/bpf_jit.c: In function ‘build_insn’: arch/loongarch/net/bpf_jit.c:727:3: error: a label can only be part of a statement and a declaration is not a statement u8 t7 = -1; ^~ arch/loongarch/net/bpf_jit.c:778:3: error: a label can only be part of a statement and a declaration is not a statement int ret; ^~~ arch/loongarch/net/bpf_jit.c:779:3: error: expected expression before ‘u64’ u64 func_addr; ^~~ arch/loongarch/net/bpf_jit.c:780:3: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement] bool func_addr_fixed; ^~~~ arch/loongarch/net/bpf_jit.c:784:11: error: ‘func_addr’ undeclared (first use in this function); did you mean ‘in_addr’? &func_addr, &func_addr_fixed); ^~~~~~~~~ in_addr arch/loongarch/net/bpf_jit.c:784:11: note: each undeclared identifier is reported only once for each function it appears in arch/loongarch/net/bpf_jit.c:814:3: error: a label can only be part of a statement and a declaration is not a statement u64 imm64 = (u64)(insn + 1)->imm << 32 | (u32)insn->imm; ^~~ Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-10-29LoongArch: Use flexible-array member instead of zero-length arrayYushan Zhou1-1/+1
Eliminate the following coccicheck warning: ./arch/loongarch/include/asm/ptrace.h:32:15-21: WARNING use flexible-array member instead Reviewed-by: WANG Xuerui <git@xen0n.name> Signed-off-by: Yushan Zhou <katrinzhou@tencent.com> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-10-29LoongArch: Remove unused kernel stack paddingJinyang He5-7/+6
The current LoongArch kernel stack is padded as if obeying the MIPS o32 calling convention (32 bytes), signifying the port's MIPS lineage but no longer making sense. Remove the padding for clarity. Reviewed-by: WANG Xuerui <git@xen0n.name> Signed-off-by: Jinyang He <hejinyang@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-10-28Merge tag 's390-6.1-3' of ↵Linus Torvalds8-29/+24
git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux Pull s390 fixes from Vasily Gorbik: - Remove outdated linux390 link from MAINTAINERS - Add few missing EX_TABLE entries to inline assemblies - Fix raw data collection for pai_ext PMU - Add kernel image secure boot trailer for future firmware versions - Fix out-of-bounds access on cio_ignore free - Fix memory allocation of mdev_types array in vfio-ap * tag 's390-6.1-3' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: s390/vfio-ap: Fix memory allocation for mdev_types array s390/cio: fix out-of-bounds access on cio_ignore free s390/pai: fix raw data collection for PMU pai_ext s390/boot: add secure boot trailer s390/pci: add missing EX_TABLE entries to __pcistg_mio_inuser()/__pcilg_mio_inuser() s390/futex: add missing EX_TABLE entry to __futex_atomic_op() s390/uaccess: add missing EX_TABLE entries to __clear_user() MAINTAINERS: remove outdated linux390 link
2022-10-28Merge tag 'riscv-for-linus-6.1-rc3' of ↵Linus Torvalds7-15/+30
git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux Pull RISC-V fixes from Palmer Dabbelt: - A fix for a build warning in the jump_label code - One of the git://github -> https://github cleanups, for the SiFive drivers - A fix for the kasan initialization code, this still likely warrants some cleanups but that's a bigger problem and at least this fixes the crashes in the short term - A pair of fixes for extension support detection on mixed LLVM/GNU toolchains - A fix for a runtime warning in the /proc/cpuinfo code * tag 'riscv-for-linus-6.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: RISC-V: Fix /proc/cpuinfo cpumask warning riscv: fix detection of toolchain Zihintpause support riscv: fix detection of toolchain Zicbom support riscv: mm: add missing memcpy in kasan_init MAINTAINERS: git://github.com -> https://github.com for sifive riscv: jump_label: mark arguments as const to satisfy asm constraints
2022-10-28Merge tag 'acpi-6.1-rc3' of ↵Linus Torvalds4-3/+11
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull ACPI and device properties fixes from Rafael Wysocki: "These fix device properties documentation and the ACPI PCC code, add a new IRQ override quirk for resource handling and add one more item to the list of device IDs to be ignored when returned by _DEP. Specifics: - Fix the documentation of the *_match_string() family of functions to properly cover the return value (Andy Shevchenko) - Fix a possible integer overflow during multiplication in the ACPI PCC code (Manank Patel) - Make the ACPI device resources code skip IRQ override on Asus Vivobook S5602ZA (Tamim Khan) - Add LATT2021 to the list of device IDs that are ignored when returned by _DEP, because there are no drivers for them in the kernel and no plans to add such drivers (Hans de Goede)" * tag 'acpi-6.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: ACPI: scan: Add LATT2021 to acpi_ignore_dep_ids[] ACPI: resource: Skip IRQ override on Asus Vivobook S5602ZA ACPI: PCC: Fix unintentional integer overflow device property: Fix documentation for *_match_string() APIs
2022-10-28Merge tag 'pm-6.1-rc3' of ↵Linus Torvalds6-209/+170
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull power management fixes from Rafael Wysocki: "These make the intel_pstate driver work as expected on all hybrid platforms to date (regardless of possible platform firmware issues), fix hybrid sleep on systems using suspend-to-idle by default, make the generic power domains code handle disabled idle states properly and update pm-graph. Specifics: - Make intel_pstate use what is known about the hardware instead of relying on information from the platform firmware (ACPI CPPC in particular) to establish the relationship between the HWP CPU performance levels and frequencies on all hybrid platforms available to date (Rafael Wysocki) - Allow hybrid sleep to use suspend-to-idle as a system suspend method if it is the current suspend method of choice (Mario Limonciello) - Fix handling of unavailable/disabled idle states in the generic power domains code (Sudeep Holla) - Update the pm-graph suite of utilities to version 5.10 which is fixes-mostly and does not add any new features (Todd Brandt)" * tag 'pm-6.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: PM: domains: Fix handling of unavailable/disabled idle states pm-graph v5.10 cpufreq: intel_pstate: hybrid: Use known scaling factor for P-cores cpufreq: intel_pstate: Read all MSRs on the target CPU PM: hibernate: Allow hybrid sleep to work with s2idle
2022-10-29random: use arch_get_random*_early() in random_init()Jean-Philippe Brucker1-2/+2
While reworking the archrandom handling, commit d349ab99eec7 ("random: handle archrandom with multiple longs") switched to the non-early archrandom helpers in random_init(), which broke initialization of the entropy pool from the arm64 random generator. Indeed at that point the arm64 CPU features, which verify that all CPUs have compatible capabilities, are not finalized so arch_get_random_seed_longs() is unsuccessful. Instead random_init() should use the _early functions, which check only the boot CPU on arm64. On other architectures the _early functions directly call the normal ones. Fixes: d349ab99eec7 ("random: handle archrandom with multiple longs") Cc: stable@vger.kernel.org Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-10-28mm: multi-gen LRU: move lru_gen_add_mm() out of IRQ-off regionSebastian Andrzej Siewior1-1/+1
lru_gen_add_mm() has been added within an IRQ-off region in the commit mentioned below. The other invocations of lru_gen_add_mm() are not within an IRQ-off region. The invocation within IRQ-off region is problematic on PREEMPT_RT because the function is using a spin_lock_t which must not be used within IRQ-disabled regions. The other invocations of lru_gen_add_mm() occur while task_struct::alloc_lock is acquired. Move lru_gen_add_mm() after interrupts are enabled and before task_unlock(). Link: https://lkml.kernel.org/r/20221026134830.711887-1-bigeasy@linutronix.de Fixes: bd74fdaea1460 ("mm: multi-gen LRU: support page table walks") Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Acked-by: Yu Zhao <yuzhao@google.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "Eric W . Biederman" <ebiederm@xmission.com> Cc: Kees Cook <keescook@chromium.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-28lib: maple_tree: remove unneeded initialization in mtree_range_walk()Lukas Bulwahn1-2/+2
Before the do-while loop in mtree_range_walk(), the variables next, min, max need to be initialized. The variables last, prev_min and prev_max are set within the loop body before they are eventually used after exiting the loop body. As it is a do-while loop, the loop body is executed at least once, so the variables last, prev_min and prev_max do not need to be initialized before the loop body. Remove unneeded initialization of last and prev_min. The needless initialization was reported by clang-analyzer as Dead Stores. As the compiler already identifies these assignments as unneeded, it optimizes the assignments away. Hence: No functional change. No change in object code. Link: https://lkml.kernel.org/r/20221026120029.12555-2-lukas.bulwahn@gmail.com Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-28mmap: fix remap_file_pages() regressionLiam Howlett1-0/+3
When using the VMA iterator, the final execution will set the variable 'next' to NULL which causes the function to fail out. Restore the break in the loop to exit the VMA iterator early without clearing NULL fixes the issue. Link: https://lore.kernel.org/lkml/29344.1666681759@jrobl/ Link: https://lkml.kernel.org/r/20221025161222.2634030-1-Liam.Howlett@oracle.com Fixes: 763ecb035029 (mm: remove the vma linked list) Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Reported-by: "J. R. Okajima" <hooanon05g@gmail.com> Tested-by: "J. R. Okajima" <hooanon05g@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-28mm/shmem: ensure proper fallback if page faultsIra Weiny1-0/+17
The kernel test robot flagged a recursive lock as a result of a conversion from kmap_atomic() to kmap_local_folio()[Link] The cause was due to the code depending on the kmap_atomic() side effect of disabling page faults. In that case the code expects the fault to fail and take the fallback case. git archaeology implied that the recursion may not be an actual bug.[1] However, depending on the implementation of the mmap_lock and the condition of the call there may still be a deadlock.[2] So this is not purely a lockdep issue. Considering a single threaded call stack there are 3 options. 1) Different mm's are in play (no issue) 2) Readlock implementation is recursive and same mm is in play (no issue) 3) Readlock implementation is _not_ recursive (issue) The mmap_lock is recursive so with a single thread there is no issue. However, Matthew pointed out a deadlock scenario when you consider additional process' and threads thusly. "The readlock implementation is only recursive if nobody else has taken a write lock. If you have a multithreaded process, one of the other threads can call mmap() and that will prevent recursion (due to fairness). Even if it's a different process that you're trying to acquire the mmap read lock on, you can still get into a deadly embrace. eg: process A thread 1 takes read lock on own mmap_lock process A thread 2 calls mmap, blocks taking write lock process B thread 1 takes page fault, read lock on own mmap lock process B thread 2 calls mmap, blocks taking write lock process A thread 1 blocks taking read lock on process B process B thread 1 blocks taking read lock on process A Now all four threads are blocked waiting for each other." Regardless using pagefault_disable() ensures that no matter what locking implementation is used a deadlock will not occur. Add an explicit pagefault_disable() and a big comment to explain this for future souls looking at this code. [1] https://lore.kernel.org/all/Y1MymJ%2FINb45AdaY@iweiny-desk3/ [2] https://lore.kernel.org/lkml/Y1bXBtGTCym77%2FoD@casper.infradead.org/ Link: https://lkml.kernel.org/r/20221025220108.2366043-1-ira.weiny@intel.com Link: https://lore.kernel.org/r/202210211215.9dc6efb5-yujie.liu@intel.com Fixes: 7a7256d5f512 ("shmem: convert shmem_mfill_atomic_pte() to use a folio") Signed-off-by: Ira Weiny <ira.weiny@intel.com> Reported-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reported-by: kernel test robot <yujie.liu@intel.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Peter Xu <peterx@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-10-28mm/userfaultfd: replace kmap/kmap_atomic() with kmap_local_page()Ira Weiny1-4/+21
kmap() and kmap_atomic() are being deprecated in favor of kmap_local_page() which is appropriate for any thread local context.[1] A recent locking bug report with userfaultfd showed that the conversion of the kmap_atomic()'s in those code flows requires care with regard to the prevention of deadlock.[2] git archaeology implied that the recursion may not be an actual bug.[3] However, depending on the implementation of the mmap_lock and the condition of the call there may still be a deadlock.[4] So this is not purely a lockdep issue. Considering a single threaded call stack there are 3 options. 1) Different mm's are in play (no issue) 2) Readlock implementation is recursive and same mm is in play (no issue) 3) Readlock implementation is _not_ recursive (issue) The mmap_lock is recursive so with a single thread there is no issue. However, Matthew pointed out a deadlock scenario when you consider additional process' and threads thusly. "The readlock implementation is only recursive if nobody else has taken a write lock. If you have a multithreaded process, one of the other threads can call mmap() and that will prevent recursion (due to fairness). Even if it's a different process that you're trying to acquire the mmap read lock on, you can still get into a deadly embrace. eg: process A thread 1 takes read lock on own mmap_lock process A thread 2 calls mmap, blocks taking write lock process B thread 1 takes page fault, read lock on own mmap lock process B thread 2 calls mmap, blocks taking write lock process A thread 1 blocks taking read lock on process B process B thread 1 blocks taking read lock on process A Now all four threads are blocked waiting for each other." Regardless using pagefault_disable() ensures that no matter what locking implementation is used a deadlock will not occur. Complete kmap conversion in userfaultfd by replacing the kmap() and kmap_atomic() calls with kmap_local_page(). When replacing the kmap_atomic() call ensure page faults continue to be disabled to support the correct fall back behavior and add a comment to inform future souls of the requirement. [1] https://lore.kernel.org/all/20220813220034.806698-1-ira.weiny@intel.com/ [2] https://lore.kernel.org/all/Y1Mh2S7fUGQ%2FiKFR@iweiny-desk3/ [3] https://lore.kernel.org/all/Y1MymJ%2FINb45AdaY@iweiny-desk3/ [4] https://lore.kernel.org/lkml/Y1bXBtGTCym77%2FoD@casper.infradead.org/ [ira.weiny@intel.com: v2] Link: https://lkml.kernel.org/r/20221025220136.2366143-1-ira.weiny@intel.com Link: https://lkml.kernel.org/r/20221024043452.1491677-1-ira.weiny@intel.com Signed-off-by: Ira Weiny <ira.weiny@intel.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Peter Xu <peterx@redhat.com> Cc: Axel Rasmussen <axelrasmussen@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>