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2016-11-29Re-enable CONFIG_MODVERSIONS in a slightly weaker formLinus Torvalds1-1/+0
This enables CONFIG_MODVERSIONS again, but allows for missing symbol CRC information in order to work around the issue that newer binutils versions seem to occasionally drop the CRC on the floor. binutils 2.26 seems to work fine, while binutils 2.27 seems to break MODVERSIONS of symbols that have been defined in assembler files. [ We've had random missing CRC's before - it may be an old problem that just is now reliably triggered with the weak asm symbols and a new version of binutils ] Some day I really do want to remove MODVERSIONS entirely. Sadly, today does not appear to be that day: Debian people apparently do want the option to enable MODVERSIONS to make it easier to have external modules across kernel versions, and this seems to be a fairly minimal fix for the annoying problem. Cc: Ben Hutchings <ben@decadent.org.uk> Acked-by: Michal Marek <mmarek@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-11-25Fix subtle CONFIG_MODVERSIONS problemsLinus Torvalds1-0/+1
CONFIG_MODVERSIONS has been broken for pretty much the whole 4.9 series, and quite frankly, nobody has cared very deeply. We absolutely know how to fix it, and it's not _complicated_, but it's not exactly pretty either. This oneliner fixes it without the ugliness, and allows for further future cleanups. "We've secretly replaced their regular MODVERSIONS with nothing at all, let's see if they notice" Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-11-24init: use pr_cont() when displaying rotator during ramdisk loading.Nicolas Schichan1-1/+1
Otherwise each individual rotator char would be printed in a new line: (...) [ 0.642350] - [ 0.644374] | [ 0.646367] - (...) Signed-off-by: Nicolas Schichan <nicolas.schichan@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-15Merge tag 'gcc-plugins-v4.9-rc1' of ↵Linus Torvalds1-0/+1
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull gcc plugins update from Kees Cook: "This adds a new gcc plugin named "latent_entropy". It is designed to extract as much possible uncertainty from a running system at boot time as possible, hoping to capitalize on any possible variation in CPU operation (due to runtime data differences, hardware differences, SMP ordering, thermal timing variation, cache behavior, etc). At the very least, this plugin is a much more comprehensive example for how to manipulate kernel code using the gcc plugin internals" * tag 'gcc-plugins-v4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: latent_entropy: Mark functions with __latent_entropy gcc-plugins: Add latent_entropy plugin
2016-10-14Merge branch 'kbuild' of ↵Linus Torvalds1-0/+2
git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild Pull kbuild updates from Michal Marek: - EXPORT_SYMBOL for asm source by Al Viro. This does bring a regression, because genksyms no longer generates checksums for these symbols (CONFIG_MODVERSIONS). Nick Piggin is working on a patch to fix this. Plus, we are talking about functions like strcpy(), which rarely change prototypes. - Fixes for PPC fallout of the above by Stephen Rothwell and Nick Piggin - fixdep speedup by Alexey Dobriyan. - preparatory work by Nick Piggin to allow architectures to build with -ffunction-sections, -fdata-sections and --gc-sections - CONFIG_THIN_ARCHIVES support by Stephen Rothwell - fix for filenames with colons in the initramfs source by me. * 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild: (22 commits) initramfs: Escape colons in depfile ppc: there is no clear_pages to export powerpc/64: whitelist unresolved modversions CRCs kbuild: -ffunction-sections fix for archs with conflicting sections kbuild: add arch specific post-link Makefile kbuild: allow archs to select link dead code/data elimination kbuild: allow architectures to use thin archives instead of ld -r kbuild: Regenerate genksyms lexer kbuild: genksyms fix for typeof handling fixdep: faster CONFIG_ search ia64: move exports to definitions sparc32: debride memcpy.S a bit [sparc] unify 32bit and 64bit string.h sparc: move exports to definitions ppc: move exports to definitions arm: move exports to definitions s390: move exports to definitions m68k: move exports to definitions alpha: move exports to actual definitions x86: move exports to actual definitions ...
2016-10-11relay: Use irq_work instead of plain timer for deferred wakeupPeter Zijlstra1-0/+1
Relay avoids calling wake_up_interruptible() for doing the wakeup of readers/consumers, waiting for the generation of new data, from the context of a process which produced the data. This is apparently done to prevent the possibility of a deadlock in case Scheduler itself is is generating data for the relay, after acquiring rq->lock. The following patch used a timer (to be scheduled at next jiffy), for delegating the wakeup to another context. commit 7c9cb38302e78d24e37f7d8a2ea7eed4ae5f2fa7 Author: Tom Zanussi <zanussi@comcast.net> Date: Wed May 9 02:34:01 2007 -0700 relay: use plain timer instead of delayed work relay doesn't need to use schedule_delayed_work() for waking readers when a simple timer will do. Scheduling a plain timer, at next jiffies boundary, to do the wakeup causes a significant wakeup latency for the Userspace client, which makes relay less suitable for the high-frequency low-payload use cases where the data gets generated at a very high rate, like multiple sub buffers getting filled within a milli second. Moreover the timer is re-scheduled on every newly produced sub buffer so the timer keeps getting pushed out if sub buffers are filled in a very quick succession (less than a jiffy gap between filling of 2 sub buffers). As a result relay runs out of sub buffers to store the new data. By using irq_work it is ensured that wakeup of userspace client, blocked in the poll call, is done at earliest (through self IPI or next timer tick) enabling it to always consume the data in time. Also this makes relay consistent with printk & ring buffers (trace), as they too use irq_work for deferred wake up of readers. [arnd@arndb.de: select CONFIG_IRQ_WORK] Link: http://lkml.kernel.org/r/20160912154035.3222156-1-arnd@arndb.de [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/1472906487-1559-1-git-send-email-akash.goel@intel.com Signed-off-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Akash Goel <akash.goel@intel.com> Cc: Tom Zanussi <tzanussi@gmail.com> Cc: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-10gcc-plugins: Add latent_entropy pluginEmese Revfy1-0/+1
This adds a new gcc plugin named "latent_entropy". It is designed to extract as much possible uncertainty from a running system at boot time as possible, hoping to capitalize on any possible variation in CPU operation (due to runtime data differences, hardware differences, SMP ordering, thermal timing variation, cache behavior, etc). At the very least, this plugin is a much more comprehensive example for how to manipulate kernel code using the gcc plugin internals. The need for very-early boot entropy tends to be very architecture or system design specific, so this plugin is more suited for those sorts of special cases. The existing kernel RNG already attempts to extract entropy from reliable runtime variation, but this plugin takes the idea to a logical extreme by permuting a global variable based on any variation in code execution (e.g. a different value (and permutation function) is used to permute the global based on loop count, case statement, if/then/else branching, etc). To do this, the plugin starts by inserting a local variable in every marked function. The plugin then adds logic so that the value of this variable is modified by randomly chosen operations (add, xor and rol) and random values (gcc generates separate static values for each location at compile time and also injects the stack pointer at runtime). The resulting value depends on the control flow path (e.g., loops and branches taken). Before the function returns, the plugin mixes this local variable into the latent_entropy global variable. The value of this global variable is added to the kernel entropy pool in do_one_initcall() and _do_fork(), though it does not credit any bytes of entropy to the pool; the contents of the global are just used to mix the pool. Additionally, the plugin can pre-initialize arrays with build-time random contents, so that two different kernel builds running on identical hardware will not have the same starting values. Signed-off-by: Emese Revfy <re.emese@gmail.com> [kees: expanded commit message and code comments] Signed-off-by: Kees Cook <keescook@chromium.org>
2016-10-07Merge branch 'parisc-4.9-1' of ↵Linus Torvalds1-6/+0
git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux Pull parisc updates from Helge Deller: "Changes include: - Fix boot of 32bit SMP kernel (initial kernel mapping was too small) - Added hardened usercopy checks - Drop bootmem and switch to memblock and NO_BOOTMEM implementation - Drop the BROKEN_RODATA config option (and thus remove the relevant code from the generic headers and files because parisc was the last architecture which used this config option) - Improve segfault reporting by printing human readable error strings - Various smaller changes, e.g. dwarf debug support for assembly code, update comments regarding copy_user_page_asm, switch to kmalloc_array()" * 'parisc-4.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux: parisc: Increase KERNEL_INITIAL_SIZE for 32-bit SMP kernels parisc: Drop bootmem and switch to memblock parisc: Add hardened usercopy feature parisc: Add cfi_startproc and cfi_endproc to assembly code parisc: Move hpmc stack into page aligned bss section parisc: Fix self-detected CPU stall warnings on Mako machines parisc: Report trap type as human readable string parisc: Update comment regarding implementation of copy_user_page_asm parisc: Use kmalloc_array() in add_system_map_addresses() parisc: Check return value of smp_boot_one_cpu() parisc: Drop BROKEN_RODATA config option
2016-09-20parisc: Drop BROKEN_RODATA config optionHelge Deller1-6/+0
PARISC was the only architecture which selected the BROKEN_RODATA config option. Drop it and remove the special handling from init.h as well. Signed-off-by: Helge Deller <deller@gmx.de>
2016-09-16sched/core: Add try_get_task_stack() and put_task_stack()Andy Lutomirski1-0/+3
There are a few places in the kernel that access stack memory belonging to a different task. Before we can start freeing task stacks before the task_struct is freed, we need a way for those code paths to pin the stack. Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jann Horn <jann@thejh.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/17a434f50ad3d77000104f21666575e10a9c1fbd.1474003868.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-09-15sched/core: Allow putting thread_info into task_structAndy Lutomirski2-2/+12
If an arch opts in by setting CONFIG_THREAD_INFO_IN_TASK_STRUCT, then thread_info is defined as a single 'u32 flags' and is the first entry of task_struct. thread_info::task is removed (it serves no purpose if thread_info is embedded in task_struct), and thread_info::cpu gets its own slot in task_struct. This is heavily based on a patch written by Linus. Originally-from: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jann Horn <jann@thejh.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/a0898196f0476195ca02713691a5037a14f2aac5.1473801993.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-09-09kbuild: allow archs to select link dead code/data eliminationNicholas Piggin1-0/+2
Introduce LD_DEAD_CODE_DATA_ELIMINATION option for architectures to select to build with -ffunction-sections, -fdata-sections, and link with --gc-sections. It requires some work (documented) to ensure all unreferenced entrypoints are live, and requires toolchain and build verification, so it is made a per-arch option for now. On a random powerpc64le build, this yelds a significant size saving, it boots and runs fine, but there is a lot I haven't tested as yet, so these savings may be reduced if there are bugs in the link. text data bss dec filename 11169741 1180744 1923176 14273661 vmlinux 10445269 1004127 1919707 13369103 vmlinux.dce ~700K text, ~170K data, 6% removed from kernel image size. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michal Marek <mmarek@suse.com>
2016-08-08Merge tag 'usercopy-v4.8' of ↵Linus Torvalds1-0/+2
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull usercopy protection from Kees Cook: "Tbhis implements HARDENED_USERCOPY verification of copy_to_user and copy_from_user bounds checking for most architectures on SLAB and SLUB" * tag 'usercopy-v4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: mm: SLUB hardened usercopy support mm: SLAB hardened usercopy support s390/uaccess: Enable hardened usercopy sparc/uaccess: Enable hardened usercopy powerpc/uaccess: Enable hardened usercopy ia64/uaccess: Enable hardened usercopy arm64/uaccess: Enable hardened usercopy ARM: uaccess: Enable hardened usercopy x86/uaccess: Enable hardened usercopy mm: Hardened usercopy mm: Implement stack frame object validation mm: Add is_migrate_cma_page
2016-08-02init/Kconfig: add clarification for out-of-tree modulesValdis Kletnieks1-1/+1
It doesn't trim just symbols that are totally unused in-tree - it trims the symbols unused by any in-tree modules actually built. If you've done a 'make localmodconfig' and only build a hundred or so modules, it's pretty likely that your out-of-tree module will come up lacking something... Hopefully this will save the next guy from a Homer Simpson "D'oh!" moment. Link: http://lkml.kernel.org/r/10177.1469787292@turing-police.cc.vt.edu Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu> Cc: Michal Marek <mmarek@suse.cz> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02init/Kconfig: ban CONFIG_LOCALVERSION_AUTO with allmodconfigAlexey Dobriyan1-0/+1
Doing patches with allmodconfig kernel compiled and committing stuff into local tree have unfortunate consequence: kernel version changes (as it should) leading to recompiling and relinking of several files even if they weren't touched (or interesting at all). This and "git-whatever" figuring out current version slow down compilation for no good reason. But lets face it, "allmodconfig" kernels don't care about kernel version, they are simply compile check guinea pigs. Make LOCALVERSION_AUTO depend on !COMPILE_TEST, so it doesn't sneak into allmodconfig .config. Link: http://lkml.kernel.org/r/20160707214954.GC31678@p183.telecom.by Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Michal Marek <mmarek@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02init: allow blacklisting of module_init functionsPrarit Bhargava1-0/+6
sprint_symbol_no_offset() returns the string "function_name [module_name]" where [module_name] is not printed for built in kernel functions. This means that the blacklisting code will fail when comparing module function names with the extended string. This patch adds the functionality to block a module's module_init() function by finding the space in the string and truncating the comparison to that length. Link: http://lkml.kernel.org/r/1466124387-20446-1-git-send-email-prarit@redhat.com Signed-off-by: Prarit Bhargava <prarit@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yang Shi <yang.shi@linaro.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Kees Cook <keescook@chromium.org> Cc: Yaowei Bai <baiyaowei@cmss.chinamobile.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02treewide: replace obsolete _refok by __refFabian Frederick1-1/+1
There was only one use of __initdata_refok and __exit_refok __init_refok was used 46 times against 82 for __ref. Those definitions are obsolete since commit 312b1485fb50 ("Introduce new section reference annotations tags: __ref, __refdata, __refconst") This patch removes the following compatibility definitions and replaces them treewide. /* compatibility defines */ #define __init_refok __ref #define __initdata_refok __refdata #define __exit_refok __ref I can also provide separate patches if necessary. (One patch per tree and check in 1 month or 2 to remove old definitions) [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/1466796271-3043-1-git-send-email-fabf@skynet.be Signed-off-by: Fabian Frederick <fabf@skynet.be> Cc: Ingo Molnar <mingo@redhat.com> Cc: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02init/Kconfig: make COMPILE_TEST depend on !UMLRichard Weinberger1-0/+1
UML is a bit special since it does not have iomem nor dma. That means a lot of drivers will not build if they miss a dependency on HAS_IOMEM. s390 used to have the same issues but since it gained PCI support UML is the only stranger. We are tired of patching dozens of new drivers after every merge window just to un-break allmod/yesconfig UML builds. One could argue that a decent driver has to know on what it depends and therefore a missing HAS_IOMEM dependency is a clear driver bug. But the dependency not obvious and not everyone does UML builds with COMPILE_TEST enabled when developing a device driver. A possible solution to make these builds succeed on UML would be providing stub functions for ioremap() and friends which fail upon runtime. Another one is simply disabling COMPILE_TEST for UML. Since it is the least hassle and does not force use to fake iomem support let's do the latter. Link: http://lkml.kernel.org/r/1466152995-28367-1-git-send-email-richard@nod.at Signed-off-by: Richard Weinberger <richard@nod.at> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-02cgroup: update cgroup's document pathseokhoon.yoon1-2/+2
cgroup's document path is changed to "cgroup-v1". update it. Link: http://lkml.kernel.org/r/1470148443-6509-1-git-send-email-iamyooon@gmail.com Signed-off-by: seokhoon.yoon <iamyooon@gmail.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-28Merge branch 'for-linus' of ↵Linus Torvalds1-2/+2
git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial Pull trivial tree updates from Jiri Kosina. * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: fat: fix error message for bogus number of directory entries fat: fix typo s/supeblock/superblock/ ASoC: max9877: Remove unused function declaration dw2102: don't output spurious blank lines to the kernel log init: fix Kconfig text ARM: io: fix comment grammar ocfs: fix ocfs2_xattr_user_get() argument name scsi/qla2xxx: Remove erroneous unused macro qla82xx_get_temp_val1()
2016-07-26mm: SLUB freelist randomizationThomas Garnier1-2/+2
Implements freelist randomization for the SLUB allocator. It was previous implemented for the SLAB allocator. Both use the same configuration option (CONFIG_SLAB_FREELIST_RANDOM). The list is randomized during initialization of a new set of pages. The order on different freelist sizes is pre-computed at boot for performance. Each kmem_cache has its own randomized freelist. This security feature reduces the predictability of the kernel SLUB allocator against heap overflows rendering attacks much less stable. For example these attacks exploit the predictability of the heap: - Linux Kernel CAN SLUB overflow (https://goo.gl/oMNWkU) - Exploiting Linux Kernel Heap corruptions (http://goo.gl/EXLn95) Performance results: slab_test impact is between 3% to 4% on average for 100000 attempts without smp. It is a very focused testing, kernbench show the overall impact on the system is way lower. Before: Single thread testing ===================== 1. Kmalloc: Repeatedly allocate then free test 100000 times kmalloc(8) -> 49 cycles kfree -> 77 cycles 100000 times kmalloc(16) -> 51 cycles kfree -> 79 cycles 100000 times kmalloc(32) -> 53 cycles kfree -> 83 cycles 100000 times kmalloc(64) -> 62 cycles kfree -> 90 cycles 100000 times kmalloc(128) -> 81 cycles kfree -> 97 cycles 100000 times kmalloc(256) -> 98 cycles kfree -> 121 cycles 100000 times kmalloc(512) -> 95 cycles kfree -> 122 cycles 100000 times kmalloc(1024) -> 96 cycles kfree -> 126 cycles 100000 times kmalloc(2048) -> 115 cycles kfree -> 140 cycles 100000 times kmalloc(4096) -> 149 cycles kfree -> 171 cycles 2. Kmalloc: alloc/free test 100000 times kmalloc(8)/kfree -> 70 cycles 100000 times kmalloc(16)/kfree -> 70 cycles 100000 times kmalloc(32)/kfree -> 70 cycles 100000 times kmalloc(64)/kfree -> 70 cycles 100000 times kmalloc(128)/kfree -> 70 cycles 100000 times kmalloc(256)/kfree -> 69 cycles 100000 times kmalloc(512)/kfree -> 70 cycles 100000 times kmalloc(1024)/kfree -> 73 cycles 100000 times kmalloc(2048)/kfree -> 72 cycles 100000 times kmalloc(4096)/kfree -> 71 cycles After: Single thread testing ===================== 1. Kmalloc: Repeatedly allocate then free test 100000 times kmalloc(8) -> 57 cycles kfree -> 78 cycles 100000 times kmalloc(16) -> 61 cycles kfree -> 81 cycles 100000 times kmalloc(32) -> 76 cycles kfree -> 93 cycles 100000 times kmalloc(64) -> 83 cycles kfree -> 94 cycles 100000 times kmalloc(128) -> 106 cycles kfree -> 107 cycles 100000 times kmalloc(256) -> 118 cycles kfree -> 117 cycles 100000 times kmalloc(512) -> 114 cycles kfree -> 116 cycles 100000 times kmalloc(1024) -> 115 cycles kfree -> 118 cycles 100000 times kmalloc(2048) -> 147 cycles kfree -> 131 cycles 100000 times kmalloc(4096) -> 214 cycles kfree -> 161 cycles 2. Kmalloc: alloc/free test 100000 times kmalloc(8)/kfree -> 66 cycles 100000 times kmalloc(16)/kfree -> 66 cycles 100000 times kmalloc(32)/kfree -> 66 cycles 100000 times kmalloc(64)/kfree -> 66 cycles 100000 times kmalloc(128)/kfree -> 65 cycles 100000 times kmalloc(256)/kfree -> 67 cycles 100000 times kmalloc(512)/kfree -> 67 cycles 100000 times kmalloc(1024)/kfree -> 64 cycles 100000 times kmalloc(2048)/kfree -> 67 cycles 100000 times kmalloc(4096)/kfree -> 67 cycles Kernbench, before: Average Optimal load -j 12 Run (std deviation): Elapsed Time 101.873 (1.16069) User Time 1045.22 (1.60447) System Time 88.969 (0.559195) Percent CPU 1112.9 (13.8279) Context Switches 189140 (2282.15) Sleeps 99008.6 (768.091) After: Average Optimal load -j 12 Run (std deviation): Elapsed Time 102.47 (0.562732) User Time 1045.3 (1.34263) System Time 88.311 (0.342554) Percent CPU 1105.8 (6.49444) Context Switches 189081 (2355.78) Sleeps 99231.5 (800.358) Link: http://lkml.kernel.org/r/1464295031-26375-3-git-send-email-thgarnie@google.com Signed-off-by: Thomas Garnier <thgarnie@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-26mm: SLUB hardened usercopy supportKees Cook1-0/+1
Under CONFIG_HARDENED_USERCOPY, this adds object size checking to the SLUB allocator to catch any copies that may span objects. Includes a redzone handling fix discovered by Michael Ellerman. Based on code from PaX and grsecurity. Signed-off-by: Kees Cook <keescook@chromium.org> Tested-by: Michael Ellerman <mpe@ellerman.id.au> Reviwed-by: Laura Abbott <labbott@redhat.com>
2016-07-26mm: SLAB hardened usercopy supportKees Cook1-0/+1
Under CONFIG_HARDENED_USERCOPY, this adds object size checking to the SLAB allocator to catch any copies that may span objects. Based on code from PaX and grsecurity. Signed-off-by: Kees Cook <keescook@chromium.org> Tested-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
2016-07-25Merge branch 'timers-nohz-for-linus' of ↵Linus Torvalds1-3/+3
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull NOHZ updates from Ingo Molnar: - fix system/idle cputime leaked on cputime accounting (all nohz configs) (Rik van Riel) - remove the messy, ad-hoc irqtime account on nohz-full and make it compatible with CONFIG_IRQ_TIME_ACCOUNTING=y instead (Rik van Riel) - cleanups (Frederic Weisbecker) - remove unecessary irq disablement in the irqtime code (Rik van Riel) * 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/cputime: Drop local_irq_save/restore from irqtime_account_irq() sched/cputime: Reorganize vtime native irqtime accounting headers sched/cputime: Clean up the old vtime gen irqtime accounting completely sched/cputime: Replace VTIME_GEN irq time code with IRQ_TIME_ACCOUNTING code sched/cputime: Count actually elapsed irq & softirq time
2016-07-25Merge branch 'core-rcu-for-linus' of ↵Linus Torvalds1-0/+1
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull RCU updates from Ingo Molnar: "The main changes in this cycle were: - documentation updates - miscellaneous fixes - minor reorganization of code - torture-test updates" * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (30 commits) rcu: Correctly handle sparse possible cpus rcu: sysctl: Panic on RCU Stall rcu: Fix a typo in a comment rcu: Make call_rcu_tasks() tolerate first call with irqs disabled rcu: Disable TASKS_RCU for usermode Linux rcu: No ordering for rcu_assign_pointer() of NULL rcutorture: Fix error return code in rcu_perf_init() torture: Inflict default jitter rcuperf: Don't treat gp_exp mis-setting as a WARN rcutorture: Drop "-soundhw pcspkr" from x86 boot arguments rcutorture: Don't specify the cpu type of QEMU on PPC rcutorture: Make -soundhw a x86 specific option rcutorture: Use vmlinux as the fallback kernel image rcutorture/doc: Create initrd using dracut torture: Stop onoff task if there is only one cpu torture: Add starvation events to error summary torture: Break online and offline functions out of torture_onoff() torture: Forgive lengthy trace dumps and preemption torture: Remove CONFIG_RCU_TORTURE_TEST_RUNNABLE, simplify code torture: Simplify code, eliminate RCU_PERF_TEST_RUNNABLE ...
2016-07-14sched/cputime: Replace VTIME_GEN irq time code with IRQ_TIME_ACCOUNTING codeRik van Riel1-3/+3
The CONFIG_VIRT_CPU_ACCOUNTING_GEN irq time tracking code does not appear to currently work right. On CPUs without nohz_full=, only tick based irq time sampling is done, which breaks down when dealing with a nohz_idle CPU. On firewalls and similar systems, no ticks may happen on a CPU for a while, and the irq time spent may never get accounted properly. This can cause issues with capacity planning and power saving, which use the CPU statistics as inputs in decision making. Remove the VTIME_GEN vtime irq time code, and replace it with the IRQ_TIME_ACCOUNTING code, when selected as a config option by the user. Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Radim Krcmar <rkrcmar@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Wanpeng Li <wanpeng.li@hotmail.com> Link: http://lkml.kernel.org/r/1468421405-20056-3-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-07-06init/Kconfig: keep Expert users menu togetherRandy Dunlap1-0/+1
The "expert" menu was broken (split) such that all entries in it after KALLSYMS were displayed in the "General setup" area instead of in the "Expert users" area. Fix this by adding one kconfig dependency. Yes, the Expert users menu is fragile. Problems like this have happened several times in the past. I will attempt to isolate the Expert users menu if there is interest in that. Fixes: 4d5d5664c900 ("x86: kallsyms: disable absolute percpu symbols on !SMP") Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: stable@vger.kernel.org # 4.6 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-06-30Merge branch 'for-mingo' of ↵Ingo Molnar1-0/+1
git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu Pull RCU changes from Paul E. McKenney: - Documentation updates. Just some simple changes, no design-level additions. - Miscellaneous fixes. - Torture-test updates. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-06-24Merge branch 'akpm' (patches from Andrew)Linus Torvalds1-1/+3
Merge misc fixes from Andrew Morton: "Two weeks worth of fixes here" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (41 commits) init/main.c: fix initcall_blacklisted on ia64, ppc64 and parisc64 autofs: don't get stuck in a loop if vfs_write() returns an error mm/page_owner: avoid null pointer dereference tools/vm/slabinfo: fix spelling mistake: "Ocurrences" -> "Occurrences" fs/nilfs2: fix potential underflow in call to crc32_le oom, suspend: fix oom_reaper vs. oom_killer_disable race ocfs2: disable BUG assertions in reading blocks mm, compaction: abort free scanner if split fails mm: prevent KASAN false positives in kmemleak mm/hugetlb: clear compound_mapcount when freeing gigantic pages mm/swap.c: flush lru pvecs on compound page arrival memcg: css_alloc should return an ERR_PTR value on error memcg: mem_cgroup_migrate() may be called with irq disabled hugetlb: fix nr_pmds accounting with shared page tables Revert "mm: disable fault around on emulated access bit architecture" Revert "mm: make faultaround produce old ptes" mailmap: add Boris Brezillon's email mailmap: add Antoine Tenart's email mm, sl[au]b: add __GFP_ATOMIC to the GFP reclaim mask mm: mempool: kasan: don't poot mempool objects in quarantine ...
2016-06-24init/main.c: fix initcall_blacklisted on ia64, ppc64 and parisc64Rasmus Villemoes1-1/+3
When I replaced kasprintf("%pf") with a direct call to sprint_symbol_no_offset I must have broken the initcall blacklisting feature on the arches where dereference_function_descriptor() is non-trivial. Fixes: c8cdd2be213f (init/main.c: simplify initcall_blacklisted()) Link: http://lkml.kernel.org/r/1466027283-4065-1-git-send-email-linux@rasmusvillemoes.dk Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Yang Shi <yang.shi@linaro.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Petr Mladek <pmladek@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-06-24Clarify naming of thread info/stack allocatorsLinus Torvalds1-2/+2
We've had the thread info allocated together with the thread stack for most architectures for a long time (since the thread_info was split off from the task struct), but that is about to change. But the patches that move the thread info to be off-stack (and a part of the task struct instead) made it clear how confused the allocator and freeing functions are. Because the common case was that we share an allocation with the thread stack and the thread_info, the two pointers were identical. That identity then meant that we would have things like ti = alloc_thread_info_node(tsk, node); ... tsk->stack = ti; which certainly _worked_ (since stack and thread_info have the same value), but is rather confusing: why are we assigning a thread_info to the stack? And if we move the thread_info away, the "confusing" code just gets to be entirely bogus. So remove all this confusion, and make it clear that we are doing the stack allocation by renaming and clarifying the function names to be about the stack. The fact that the thread_info then shares the allocation is an implementation detail, and not really about the allocation itself. This is a pure renaming and type fix: we pass in the same pointer, it's just that we clarify what the pointer means. The ia64 code that actually only has one single allocation (for all of task_struct, thread_info and kernel thread stack) now looks a bit odd, but since "tsk->stack" is actually not even used there, that oddity doesn't matter. It would be a separate thing to clean that up, I intentionally left the ia64 changes as a pure brute-force renaming and type change. Acked-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-06-21init: fix Kconfig textGeert Uytterhoeven1-2/+2
[jkosina@suse.cz: folded another fix on top on the same line as spotted by Randy Dunlap] Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2016-06-15rcu: Disable TASKS_RCU for usermode LinuxPaul E. McKenney1-0/+1
Usermode Linux currently does not implement arch_irqs_disabled_flags(), which results in a build failure in TASKS_RCU. Therefore, this commit disables the TASKS_RCU Kconfig option in usermode Linux builds. The usermode Linux maintainers expect to merge arch_irqs_disabled_flags() into 4.8, at which point this commit may be reverted. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Jeff Dike <jdike@addtoit.com> Acked-by: Richard Weinberger <richard@nod.at>
2016-05-27mm: use early_pfn_to_nid in page_ext_initYang Shi1-2/+1
page_ext_init() checks suitable pages with pfn_to_nid(), but pfn_to_nid() depends on memmap which will not be setup fully until page_alloc_init_late() is done. Use early_pfn_to_nid() instead of pfn_to_nid() so that page extension could be still used early even though CONFIG_ DEFERRED_STRUCT_PAGE_INIT is enabled and catch early page allocation call sites. Suggested by Joonsoo Kim [1], this fix basically undoes the change introduced by commit b8f1a75d61d840 ("mm: call page_ext_init() after all struct pages are initialized") and fixes the same problem with a better approach. [1] http://lkml.kernel.org/r/CAAmzW4OUmyPwQjvd7QUfc6W1Aic__TyAuH80MLRZNMxKy0-wPQ@mail.gmail.com Link: http://lkml.kernel.org/r/1464198689-23458-1-git-send-email-yang.shi@linaro.org Signed-off-by: Yang Shi <yang.shi@linaro.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-26Merge branch 'kbuild' of ↵Linus Torvalds1-0/+29
git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild Pull kbuild updates from Michal Marek: - new option CONFIG_TRIM_UNUSED_KSYMS which does a two-pass build and unexports symbols which are not used in the current config [Nicolas Pitre] - several kbuild rule cleanups [Masahiro Yamada] - warning option adjustments for gcov etc [Arnd Bergmann] - a few more small fixes * 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild: (31 commits) kbuild: move -Wunused-const-variable to W=1 warning level kbuild: fix if_change and friends to consider argument order kbuild: fix adjust_autoksyms.sh for modules that need only one symbol kbuild: fix ksym_dep_filter when multiple EXPORT_SYMBOL() on the same line gcov: disable -Wmaybe-uninitialized warning gcov: disable tree-loop-im to reduce stack usage gcov: disable for COMPILE_TEST Kbuild: disable 'maybe-uninitialized' warning for CONFIG_PROFILE_ALL_BRANCHES Kbuild: change CC_OPTIMIZE_FOR_SIZE definition kbuild: forbid kernel directory to contain spaces and colons kbuild: adjust ksym_dep_filter for some cmd_* renames kbuild: Fix dependencies for final vmlinux link kbuild: better abstract vmlinux sequential prerequisites kbuild: fix call to adjust_autoksyms.sh when output directory specified kbuild: Get rid of KBUILD_STR kbuild: rename cmd_as_s_S to cmd_cpp_s_S kbuild: rename cmd_cc_i_c to cmd_cpp_i_c kbuild: drop redundant "PHONY += FORCE" kbuild: delete unnecessary "@:" kbuild: mark help target as PHONY ...
2016-05-20init/main.c: simplify initcall_blacklisted()Rasmus Villemoes1-5/+4
Using kasprintf to get the function name makes us look up the name twice, along with all the vsnprintf overhead of parsing the format string etc. It also means there is an allocation failure case to deal with. Since symbol_string in vsprintf.c would anyway allocate an array of size KSYM_SYMBOL_LEN on the stack, that might as well be done up here. Moreover, since this is a debug feature and the blacklisted_initcalls list is usually empty, we might as well test that and thus avoid looking up the symbol name even once in the common case. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Prarit Bhargava <prarit@redhat.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-20printk/nmi: increase the size of NMI buffer and make it configurablePetr Mladek1-0/+22
Testing has shown that the backtrace sometimes does not fit into the 4kB temporary buffer that is used in NMI context. The warnings are gone when I double the temporary buffer size. This patch doubles the buffer size and makes it configurable. Note that this problem existed even in the x86-specific implementation that was added by the commit a9edc8809328 ("x86/nmi: Perform a safe NMI stack trace on all CPUs"). Nobody noticed it because it did not print any warnings. Signed-off-by: Petr Mladek <pmladek@suse.com> Cc: Jan Kara <jack@suse.cz> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Russell King <rmk+kernel@arm.linux.org.uk> Cc: Daniel Thompson <daniel.thompson@linaro.org> Cc: Jiri Kosina <jkosina@suse.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: David Miller <davem@davemloft.net> Cc: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-20printk/nmi: generic solution for safe printk in NMIPetr Mladek2-0/+6
printk() takes some locks and could not be used a safe way in NMI context. The chance of a deadlock is real especially when printing stacks from all CPUs. This particular problem has been addressed on x86 by the commit a9edc8809328 ("x86/nmi: Perform a safe NMI stack trace on all CPUs"). The patchset brings two big advantages. First, it makes the NMI backtraces safe on all architectures for free. Second, it makes all NMI messages almost safe on all architectures (the temporary buffer is limited. We still should keep the number of messages in NMI context at minimum). Note that there already are several messages printed in NMI context: WARN_ON(in_nmi()), BUG_ON(in_nmi()), anything being printed out from MCE handlers. These are not easy to avoid. This patch reuses most of the code and makes it generic. It is useful for all messages and architectures that support NMI. The alternative printk_func is set when entering and is reseted when leaving NMI context. It queues IRQ work to copy the messages into the main ring buffer in a safe context. __printk_nmi_flush() copies all available messages and reset the buffer. Then we could use a simple cmpxchg operations to get synchronized with writers. There is also used a spinlock to get synchronized with other flushers. We do not longer use seq_buf because it depends on external lock. It would be hard to make all supported operations safe for a lockless use. It would be confusing and error prone to make only some operations safe. The code is put into separate printk/nmi.c as suggested by Steven Rostedt. It needs a per-CPU buffer and is compiled only on architectures that call nmi_enter(). This is achieved by the new HAVE_NMI Kconfig flag. The are MN10300 and Xtensa architectures. We need to clean up NMI handling there first. Let's do it separately. The patch is heavily based on the draft from Peter Zijlstra, see https://lkml.org/lkml/2015/6/10/327 [arnd@arndb.de: printk-nmi: use %zu format string for size_t] [akpm@linux-foundation.org: min_t->min - all types are size_t here] Signed-off-by: Petr Mladek <pmladek@suse.com> Suggested-by: Peter Zijlstra <peterz@infradead.org> Suggested-by: Steven Rostedt <rostedt@goodmis.org> Cc: Jan Kara <jack@suse.cz> Acked-by: Russell King <rmk+kernel@arm.linux.org.uk> [arm part] Cc: Daniel Thompson <daniel.thompson@linaro.org> Cc: Jiri Kosina <jkosina@suse.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: David Miller <davem@davemloft.net> Cc: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-20mm: call page_ext_init() after all struct pages are initializedYang Shi1-1/+2
When DEFERRED_STRUCT_PAGE_INIT is enabled, just a subset of memmap at boot are initialized, then the rest are initialized in parallel by starting one-off "pgdatinitX" kernel thread for each node X. If page_ext_init is called before it, some pages will not have valid extension, this may lead the below kernel oops when booting up kernel: BUG: unable to handle kernel NULL pointer dereference at (null) IP: [<ffffffff8118d982>] free_pcppages_bulk+0x2d2/0x8d0 PGD 0 Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC Modules linked in: CPU: 11 PID: 106 Comm: pgdatinit1 Not tainted 4.6.0-rc5-next-20160427 #26 Hardware name: Intel Corporation S5520HC/S5520HC, BIOS S5500.86B.01.10.0025.030220091519 03/02/2009 task: ffff88017c080040 ti: ffff88017c084000 task.ti: ffff88017c084000 RIP: 0010:[<ffffffff8118d982>] [<ffffffff8118d982>] free_pcppages_bulk+0x2d2/0x8d0 RSP: 0000:ffff88017c087c48 EFLAGS: 00010046 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000001 RDX: 0000000000000980 RSI: 0000000000000080 RDI: 0000000000660401 RBP: ffff88017c087cd0 R08: 0000000000000401 R09: 0000000000000009 R10: ffff88017c080040 R11: 000000000000000a R12: 0000000000000400 R13: ffffea0019810000 R14: ffffea0019810040 R15: ffff88066cfe6080 FS: 0000000000000000(0000) GS:ffff88066cd40000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 0000000002406000 CR4: 00000000000006e0 Call Trace: free_hot_cold_page+0x192/0x1d0 __free_pages+0x5c/0x90 __free_pages_boot_core+0x11a/0x14e deferred_free_range+0x50/0x62 deferred_init_memmap+0x220/0x3c3 kthread+0xf8/0x110 ret_from_fork+0x22/0x40 Code: 49 89 d4 48 c1 e0 06 49 01 c5 e9 de fe ff ff 4c 89 f7 44 89 4d b8 4c 89 45 c0 44 89 5d c8 48 89 4d d0 e8 62 c7 07 00 48 8b 4d d0 <48> 8b 00 44 8b 5d c8 4c 8b 45 c0 44 8b 4d b8 a8 02 0f 84 05 ff RIP [<ffffffff8118d982>] free_pcppages_bulk+0x2d2/0x8d0 RSP <ffff88017c087c48> CR2: 0000000000000000 Move page_ext_init() after page_alloc_init_late() to make sure page extension is setup for all pages. Link: http://lkml.kernel.org/r/1463696006-31360-1-git-send-email-yang.shi@linaro.org Signed-off-by: Yang Shi <yang.shi@linaro.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-19mm: SLAB freelist randomizationThomas Garnier1-0/+9
Provides an optional config (CONFIG_SLAB_FREELIST_RANDOM) to randomize the SLAB freelist. The list is randomized during initialization of a new set of pages. The order on different freelist sizes is pre-computed at boot for performance. Each kmem_cache has its own randomized freelist. Before pre-computed lists are available freelists are generated dynamically. This security feature reduces the predictability of the kernel SLAB allocator against heap overflows rendering attacks much less stable. For example this attack against SLUB (also applicable against SLAB) would be affected: https://jon.oberheide.org/blog/2010/09/10/linux-kernel-can-slub-overflow/ Also, since v4.6 the freelist was moved at the end of the SLAB. It means a controllable heap is opened to new attacks not yet publicly discussed. A kernel heap overflow can be transformed to multiple use-after-free. This feature makes this type of attack harder too. To generate entropy, we use get_random_bytes_arch because 0 bits of entropy is available in the boot stage. In the worse case this function will fallback to the get_random_bytes sub API. We also generate a shift random number to shift pre-computed freelist for each new set of pages. The config option name is not specific to the SLAB as this approach will be extended to other allocators like SLUB. Performance results highlighted no major changes: Hackbench (running 90 10 times): Before average: 0.0698 After average: 0.0663 (-5.01%) slab_test 1 run on boot. Difference only seen on the 2048 size test being the worse case scenario covered by freelist randomization. New slab pages are constantly being created on the 10000 allocations. Variance should be mainly due to getting new pages every few allocations. Before: Single thread testing ===================== 1. Kmalloc: Repeatedly allocate then free test 10000 times kmalloc(8) -> 99 cycles kfree -> 112 cycles 10000 times kmalloc(16) -> 109 cycles kfree -> 140 cycles 10000 times kmalloc(32) -> 129 cycles kfree -> 137 cycles 10000 times kmalloc(64) -> 141 cycles kfree -> 141 cycles 10000 times kmalloc(128) -> 152 cycles kfree -> 148 cycles 10000 times kmalloc(256) -> 195 cycles kfree -> 167 cycles 10000 times kmalloc(512) -> 257 cycles kfree -> 199 cycles 10000 times kmalloc(1024) -> 393 cycles kfree -> 251 cycles 10000 times kmalloc(2048) -> 649 cycles kfree -> 228 cycles 10000 times kmalloc(4096) -> 806 cycles kfree -> 370 cycles 10000 times kmalloc(8192) -> 814 cycles kfree -> 411 cycles 10000 times kmalloc(16384) -> 892 cycles kfree -> 455 cycles 2. Kmalloc: alloc/free test 10000 times kmalloc(8)/kfree -> 121 cycles 10000 times kmalloc(16)/kfree -> 121 cycles 10000 times kmalloc(32)/kfree -> 121 cycles 10000 times kmalloc(64)/kfree -> 121 cycles 10000 times kmalloc(128)/kfree -> 121 cycles 10000 times kmalloc(256)/kfree -> 119 cycles 10000 times kmalloc(512)/kfree -> 119 cycles 10000 times kmalloc(1024)/kfree -> 119 cycles 10000 times kmalloc(2048)/kfree -> 119 cycles 10000 times kmalloc(4096)/kfree -> 121 cycles 10000 times kmalloc(8192)/kfree -> 119 cycles 10000 times kmalloc(16384)/kfree -> 119 cycles After: Single thread testing ===================== 1. Kmalloc: Repeatedly allocate then free test 10000 times kmalloc(8) -> 130 cycles kfree -> 86 cycles 10000 times kmalloc(16) -> 118 cycles kfree -> 86 cycles 10000 times kmalloc(32) -> 121 cycles kfree -> 85 cycles 10000 times kmalloc(64) -> 176 cycles kfree -> 102 cycles 10000 times kmalloc(128) -> 178 cycles kfree -> 100 cycles 10000 times kmalloc(256) -> 205 cycles kfree -> 109 cycles 10000 times kmalloc(512) -> 262 cycles kfree -> 136 cycles 10000 times kmalloc(1024) -> 342 cycles kfree -> 157 cycles 10000 times kmalloc(2048) -> 701 cycles kfree -> 238 cycles 10000 times kmalloc(4096) -> 803 cycles kfree -> 364 cycles 10000 times kmalloc(8192) -> 835 cycles kfree -> 404 cycles 10000 times kmalloc(16384) -> 896 cycles kfree -> 441 cycles 2. Kmalloc: alloc/free test 10000 times kmalloc(8)/kfree -> 121 cycles 10000 times kmalloc(16)/kfree -> 121 cycles 10000 times kmalloc(32)/kfree -> 123 cycles 10000 times kmalloc(64)/kfree -> 142 cycles 10000 times kmalloc(128)/kfree -> 121 cycles 10000 times kmalloc(256)/kfree -> 119 cycles 10000 times kmalloc(512)/kfree -> 119 cycles 10000 times kmalloc(1024)/kfree -> 119 cycles 10000 times kmalloc(2048)/kfree -> 119 cycles 10000 times kmalloc(4096)/kfree -> 119 cycles 10000 times kmalloc(8192)/kfree -> 119 cycles 10000 times kmalloc(16384)/kfree -> 119 cycles [akpm@linux-foundation.org: propagate gfp_t into cache_random_seq_create()] Signed-off-by: Thomas Garnier <thgarnie@google.com> Acked-by: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kees Cook <keescook@chromium.org> Cc: Greg Thelen <gthelen@google.com> Cc: Laura Abbott <labbott@fedoraproject.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-10Kbuild: change CC_OPTIMIZE_FOR_SIZE definitionArnd Bergmann1-0/+13
CC_OPTIMIZE_FOR_SIZE disables the often useful -Wmaybe-unused warning, because that causes a ridiculous amount of false positives when combined with -Os. This means a lot of warnings don't show up in testing by the developers that should see them with an 'allmodconfig' kernel that has CC_OPTIMIZE_FOR_SIZE enabled, but only later in randconfig builds that don't. This changes the Kconfig logic around CC_OPTIMIZE_FOR_SIZE to make it a 'choice' statement defaulting to CC_OPTIMIZE_FOR_PERFORMANCE that gets added for this purpose. The allmodconfig and allyesconfig kernels now default to -O2 with the maybe-unused warning enabled. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Michal Marek <mmarek@suse.com>
2016-04-01Make CONFIG_FHANDLE default yAndi Kleen1-1/+2
Newer Fedora and OpenSUSE didn't boot with my standard configuration. It took me some time to figure out why, in fact I had to write a script to try different config options systematically. The problem is that something (systemd) in dracut depends on CONFIG_FHANDLE, which adds open by file handle syscalls. While it is set in defconfigs it is very easy to miss when updating older configs because it is not default y. Make it default y and also depend on EXPERT, as dracut use is likely widespread. Signed-off-by: Andi Kleen <ak@linux.intel.com> Cc: Richard Weinberger <richard.weinberger@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-29kconfig option for TRIM_UNUSED_KSYMSNicolas Pitre1-0/+16
The config option to enable it all. Signed-off-by: Nicolas Pitre <nico@linaro.org> Acked-by: Rusty Russell <rusty@rustcorp.com.au>
2016-03-18Merge branch 'for-4.6' of ↵Linus Torvalds1-2/+2
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup updates from Tejun Heo: "cgroup changes for v4.6-rc1. No userland visible behavior changes in this pull request. I'll send out a separate pull request for the addition of cgroup namespace support. - The biggest change is the revamping of cgroup core task migration and controller handling logic. There are quite a few places where controllers and tasks are manipulated. Previously, many of those places implemented custom operations for each specific use case assuming specific starting conditions. While this worked, it makes the code fragile and difficult to follow. The bulk of this pull request restructures these operations so that most related operations are performed through common helpers which implement recursive (subtrees are always processed consistently) and idempotent (they make cgroup hierarchy converge to the target state rather than performing operations assuming specific starting conditions). This makes the code a lot easier to understand, verify and extend. - Implicit controller support is added. This is primarily for using perf_event on the v2 hierarchy so that perf can match cgroup v2 path without requiring the user to do anything special. The kernel portion of perf_event changes is acked but userland changes are still pending review. - cgroup_no_v1= boot parameter added to ease testing cgroup v2 in certain environments. - There is a regression introduced during v4.4 devel cycle where attempts to migrate zombie tasks can mess up internal object management. This was fixed earlier this week and included in this pull request w/ stable cc'd. - Misc non-critical fixes and improvements" * 'for-4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (44 commits) cgroup: avoid false positive gcc-6 warning cgroup: ignore css_sets associated with dead cgroups during migration Documentation: cgroup v2: Trivial heading correction. cgroup: implement cgroup_subsys->implicit_on_dfl cgroup: use css_set->mg_dst_cgrp for the migration target cgroup cgroup: make cgroup[_taskset]_migrate() take cgroup_root instead of cgroup cgroup: move migration destination verification out of cgroup_migrate_prepare_dst() cgroup: fix incorrect destination cgroup in cgroup_update_dfl_csses() cgroup: Trivial correction to reflect controller. cgroup: remove stale item in cgroup-v1 document INDEX file. cgroup: update css iteration in cgroup_update_dfl_csses() cgroup: allocate 2x cgrp_cset_links when setting up a new root cgroup: make cgroup_calc_subtree_ss_mask() take @this_ss_mask cgroup: reimplement rebind_subsystems() using cgroup_apply_control() and friends cgroup: use cgroup_apply_enable_control() in cgroup creation path cgroup: combine cgroup_mutex locking and offline css draining cgroup: factor out cgroup_{apply|finalize}_control() from cgroup_subtree_control_write() cgroup: introduce cgroup_{save|propagate|restore}_control() cgroup: make cgroup_drain_offline() and cgroup_apply_control_{disable|enable}() recursive cgroup: factor out cgroup_apply_control_enable() from cgroup_subtree_control_write() ...
2016-03-17Merge branch 'next' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security Pull security layer updates from James Morris: "There are a bunch of fixes to the TPM, IMA, and Keys code, with minor fixes scattered across the subsystem. IMA now requires signed policy, and that policy is also now measured and appraised" * 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security: (67 commits) X.509: Make algo identifiers text instead of enum akcipher: Move the RSA DER encoding check to the crypto layer crypto: Add hash param to pkcs1pad sign-file: fix build with CMS support disabled MAINTAINERS: update tpmdd urls MODSIGN: linux/string.h should be #included to get memcpy() certs: Fix misaligned data in extra certificate list X.509: Handle midnight alternative notation in GeneralizedTime X.509: Support leap seconds Handle ISO 8601 leap seconds and encodings of midnight in mktime64() X.509: Fix leap year handling again PKCS#7: fix unitialized boolean 'want' firmware: change kernel read fail to dev_dbg() KEYS: Use the symbol value for list size, updated by scripts/insert-sys-cert KEYS: Reserve an extra certificate symbol for inserting without recompiling modsign: hide openssl output in silent builds tpm_tis: fix build warning with tpm_tis_resume ima: require signed IMA policy ima: measure and appraise the IMA policy itself ima: load policy using path ...
2016-03-16Merge branch 'akpm' (patches from Andrew)Linus Torvalds2-3/+23
Merge first patch-bomb from Andrew Morton: - some misc things - ofs2 updates - about half of MM - checkpatch updates - autofs4 update * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (120 commits) autofs4: fix string.h include in auto_dev-ioctl.h autofs4: use pr_xxx() macros directly for logging autofs4: change log print macros to not insert newline autofs4: make autofs log prints consistent autofs4: fix some white space errors autofs4: fix invalid ioctl return in autofs4_root_ioctl_unlocked() autofs4: fix coding style line length in autofs4_wait() autofs4: fix coding style problem in autofs4_get_set_timeout() autofs4: coding style fixes autofs: show pipe inode in mount options kallsyms: add support for relative offsets in kallsyms address table kallsyms: don't overload absolute symbol type for percpu symbols x86: kallsyms: disable absolute percpu symbols on !SMP checkpatch: fix another left brace warning checkpatch: improve UNSPECIFIED_INT test for bare signed/unsigned uses checkpatch: warn on bare unsigned or signed declarations without int checkpatch: exclude asm volatile from complex macro check mm: memcontrol: drop unnecessary lru locking from mem_cgroup_migrate() mm: migrate: consolidate mem_cgroup_migrate() calls mm/compaction: speed up pageblock_pfn_to_page() when zone is contiguous ...
2016-03-15kallsyms: add support for relative offsets in kallsyms address tableArd Biesheuvel1-0/+18
Similar to how relative extables are implemented, it is possible to emit the kallsyms table in such a way that it contains offsets relative to some anchor point in the kernel image rather than absolute addresses. On 64-bit architectures, it cuts the size of the kallsyms address table in half, since offsets between kernel symbols can typically be expressed in 32 bits. This saves several hundreds of kilobytes of permanent .rodata on average. In addition, the kallsyms address table is no longer subject to dynamic relocation when CONFIG_RELOCATABLE is in effect, so the relocation work done after decompression now doesn't have to do relocation updates for all these values. This saves up to 24 bytes (i.e., the size of a ELF64 RELA relocation table entry) per value, which easily adds up to a couple of megabytes of uncompressed __init data on ppc64 or arm64. Even if these relocation entries typically compress well, the combined size reduction of 2.8 MB uncompressed for a ppc64_defconfig build (of which 2.4 MB is __init data) results in a ~500 KB space saving in the compressed image. Since it is useful for some architectures (like x86) to retain the ability to emit absolute values as well, this patch also adds support for capturing both absolute and relative values when KALLSYMS_ABSOLUTE_PERCPU is in effect, by emitting absolute per-cpu addresses as positive 32-bit values, and addresses relative to the lowest encountered relative symbol as negative values, which are subtracted from the runtime address of this base symbol to produce the actual address. Support for the above is enabled by default for all architectures except IA-64 and Tile-GX, whose symbols are too far apart to capture in this manner. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Tested-by: Guenter Roeck <linux@roeck-us.net> Reviewed-by: Kees Cook <keescook@chromium.org> Tested-by: Kees Cook <keescook@chromium.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Ingo Molnar <mingo@kernel.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Michal Marek <mmarek@suse.cz> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-15x86: kallsyms: disable absolute percpu symbols on !SMPArd Biesheuvel1-0/+4
scripts/kallsyms.c has a special --absolute-percpu command line option which deals with the zero based per cpu offsets that are used when building for SMP on x86_64. This means that the option should only be passed in that case, so add a Kconfig symbol with the correct predicate, and use that instead. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Tested-by: Guenter Roeck <linux@roeck-us.net> Reviewed-by: Kees Cook <keescook@chromium.org> Tested-by: Kees Cook <keescook@chromium.org> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Ingo Molnar <mingo@kernel.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Michal Marek <mmarek@suse.cz> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-15init/main.c: use list_for_each_entry()Geliang Tang1-3/+1
Use list_for_each_entry() instead of list_for_each() to simplify the code. Signed-off-by: Geliang Tang <geliangtang@163.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-15Merge branch 'smp-hotplug-for-linus' of ↵Linus Torvalds1-15/+1
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull cpu hotplug updates from Thomas Gleixner: "This is the first part of the ongoing cpu hotplug rework: - Initial implementation of the state machine - Runs all online and prepare down callbacks on the plugged cpu and not on some random processor - Replaces busy loop waiting with completions - Adds tracepoints so the states can be followed" More detailed commentary on this work from an earlier email: "What's wrong with the current cpu hotplug infrastructure? - Asymmetry The hotplug notifier mechanism is asymmetric versus the bringup and teardown. This is mostly caused by the notifier mechanism. - Largely undocumented dependencies While some notifiers use explicitely defined notifier priorities, we have quite some notifiers which use numerical priorities to express dependencies without any documentation why. - Control processor driven Most of the bringup/teardown of a cpu is driven by a control processor. While it is understandable, that preperatory steps, like idle thread creation, memory allocation for and initialization of essential facilities needs to be done before a cpu can boot, there is no reason why everything else must run on a control processor. Before this patch series, bringup looks like this: Control CPU Booting CPU do preparatory steps kick cpu into life do low level init sync with booting cpu sync with control cpu bring the rest up - All or nothing approach There is no way to do partial bringups. That's something which is really desired because we waste e.g. at boot substantial amount of time just busy waiting that the cpu comes to life. That's stupid as we could very well do preparatory steps and the initial IPI for other cpus and then go back and do the necessary low level synchronization with the freshly booted cpu. - Minimal debuggability Due to the notifier based design, it's impossible to switch between two stages of the bringup/teardown back and forth in order to test the correctness. So in many hotplug notifiers the cancel mechanisms are either not existant or completely untested. - Notifier [un]registering is tedious To [un]register notifiers we need to protect against hotplug at every callsite. There is no mechanism that bringup/teardown callbacks are issued on the online cpus, so every caller needs to do it itself. That also includes error rollback. What's the new design? The base of the new design is a symmetric state machine, where both the control processor and the booting/dying cpu execute a well defined set of states. Each state is symmetric in the end, except for some well defined exceptions, and the bringup/teardown can be stopped and reversed at almost all states. So the bringup of a cpu will look like this in the future: Control CPU Booting CPU do preparatory steps kick cpu into life do low level init sync with booting cpu sync with control cpu bring itself up The synchronization step does not require the control cpu to wait. That mechanism can be done asynchronously via a worker or some other mechanism. The teardown can be made very similar, so that the dying cpu cleans up and brings itself down. Cleanups which need to be done after the cpu is gone, can be scheduled asynchronously as well. There is a long way to this, as we need to refactor the notion when a cpu is available. Today we set the cpu online right after it comes out of the low level bringup, which is not really correct. The proper mechanism is to set it to available, i.e. cpu local threads, like softirqd, hotplug thread etc. can be scheduled on that cpu, and once it finished all booting steps, it's set to online, so general workloads can be scheduled on it. The reverse happens on teardown. First thing to do is to forbid scheduling of general workloads, then teardown all the per cpu resources and finally shut it off completely. This patch series implements the basic infrastructure for this at the core level. This includes the following: - Basic state machine implementation with well defined states, so ordering and prioritization can be expressed. - Interfaces to [un]register state callbacks This invokes the bringup/teardown callback on all online cpus with the proper protection in place and [un]installs the callbacks in the state machine array. For callbacks which have no particular ordering requirement we have a dynamic state space, so that drivers don't have to register an explicit hotplug state. If a callback fails, the code automatically does a rollback to the previous state. - Sysfs interface to drive the state machine to a particular step. This is only partially functional today. Full functionality and therefor testability will be achieved once we converted all existing hotplug notifiers over to the new scheme. - Run all CPU_ONLINE/DOWN_PREPARE notifiers on the booting/dying processor: Control CPU Booting CPU do preparatory steps kick cpu into life do low level init sync with booting cpu sync with control cpu wait for boot bring itself up Signal completion to control cpu In a previous step of this work we've done a full tree mechanical conversion of all hotplug notifiers to the new scheme. The balance is a net removal of about 4000 lines of code. This is not included in this series, as we decided to take a different approach. Instead of mechanically converting everything over, we will do a proper overhaul of the usage sites one by one so they nicely fit into the symmetric callback scheme. I decided to do that after I looked at the ugliness of some of the converted sites and figured out that their hotplug mechanism is completely buggered anyway. So there is no point to do a mechanical conversion first as we need to go through the usage sites one by one again in order to achieve a full symmetric and testable behaviour" * 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits) cpu/hotplug: Document states better cpu/hotplug: Fix smpboot thread ordering cpu/hotplug: Remove redundant state check cpu/hotplug: Plug death reporting race rcu: Make CPU_DYING_IDLE an explicit call cpu/hotplug: Make wait for dead cpu completion based cpu/hotplug: Let upcoming cpu bring itself fully up arch/hotplug: Call into idle with a proper state cpu/hotplug: Move online calls to hotplugged cpu cpu/hotplug: Create hotplug threads cpu/hotplug: Split out the state walk into functions cpu/hotplug: Unpark smpboot threads from the state machine cpu/hotplug: Move scheduler cpu_online notifier to hotplug core cpu/hotplug: Implement setup/removal interface cpu/hotplug: Make target state writeable cpu/hotplug: Add sysfs state interface cpu/hotplug: Hand in target state to _cpu_up/down cpu/hotplug: Convert the hotplugged cpu work to a state machine cpu/hotplug: Convert to a state machine for the control processor cpu/hotplug: Add tracepoints ...
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