- 04 Jun, 2017 26 commits
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Thomas Gleixner authored
Replace the hrtimer calls by calls to the new try_to_cancel()/arm() kclock callbacks and move the hrtimer specific implementation into the corresponding callback functions. Signed-off-by:
Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: John Stultz <john.stultz@linaro.org> Link: http://lkml.kernel.org/r/20170530211657.355396667@linutronix.de
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Thomas Gleixner authored
Add timer_try_to_cancel() and timer_arm() callbacks to kclock which allow to make common_timer_set() usable by both hrtimer and alarmtimer based clocks. Signed-off-by:
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Thomas Gleixner authored
Zero out the settings struct in the common code so the callbacks do not have to do it themself. Signed-off-by:
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Thomas Gleixner authored
Replace the hrtimer calls by calls to the new forward/remaining kclock callbacks and move the hrtimer specific implementation into the corresponding callback functions. Signed-off-by:
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Thomas Gleixner authored
Add two callbacks to kclock which allow using common_)timer_get() for both hrtimer and alarm timer based clocks. Signed-off-by:
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Thomas Gleixner authored
Keep track of the activation state of posix timers. This is a preparatory change for making common_timer_get() usable by both hrtimer and alarm timer implementations. Signed-off-by:
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Thomas Gleixner authored
Use the new timer_rearm() callback to replace the conditional hardcoded calls into the hrtimer and cpu timer code. This allows later to bring the same logic to alarmtimers. Signed-off-by:
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Thomas Gleixner authored
That function is a misnomer. Rename it with a proper prefix to posixtimer_rearm(). Signed-off-by:
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Thomas Gleixner authored
Add a timer_rearm() callback which is used to make the rescheduling of posix interval timers independent of the underlying clock implementation. Signed-off-by:
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Thomas Gleixner authored
Having the k_clock pointer in the k_itimer struct avoids the lookup in several code pathes and makes the next steps of unification of the hrtimer and alarmtimer based posix timers simpler. Signed-off-by:
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Thomas Gleixner authored
Preparatory patch to unify the alarm timer and hrtimer based posix interval timer handling. The interval is used as a criteria for rearming decisions so moving it out of the clock specific data structures allows later unification. Signed-off-by:
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Thomas Gleixner authored
hrtimer based posix-timers and posix-cpu-timers handle the update of the rearming and overflow related status fields differently. Move that update to the common rearming code. Signed-off-by:
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Thomas Gleixner authored
None of these declarations is required outside of kernel/time. Move them to an internal header. Signed-off-by:
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Thomas Gleixner authored
As a preparation for further changes, cleanup the formatting of the k_itimer structure and add kernel doc comments. Signed-off-by:
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Thomas Gleixner authored
Move it below the actual implementations as there are new callbacks coming which would require even more forward declarations. Signed-off-by:
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Thomas Gleixner authored
The only user of this facility is ptp_clock, which does not implement any of those functions. Remove them to prevent accidental users. Especially the interval timer interfaces are now more or less impossible to implement because the necessary infrastructure has been confined to the core code. Aside of that it's really complex to make these callbacks implemented according to spec as the alarm timer implementation demonstrates. If at all then a nanosleep callback might be a reasonable extension. For now keep just what ptp_clock needs. Signed-off-by:
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Thomas Gleixner authored
Since the removal of the mmtimer driver the export is not longer needed. Signed-off-by:
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Thomas Gleixner authored
Having a IF_ENABLED(CONFIG_POSIX_TIMERS) inside of a #ifdef CONFIG_POSIX_TIMERS section is pointless. Signed-off-by:
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Thomas Gleixner authored
Pick up urgent fixes to avoid conflicts.
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Thomas Gleixner authored
The alarmtimer code has another source of potentially rearming itself too fast. Interval timers with a very samll interval have a similar CPU hog effect as the previously fixed overflow issue. The reason is that alarmtimers do not implement the normal protection against this kind of problem which the other posix timer use: timer expires -> queue signal -> deliver signal -> rearm timer This scheme brings the rearming under scheduler control and prevents permanently firing timers which hog the CPU. Bringing this scheme to the alarm timer code is a major overhaul because it lacks all the necessary mechanisms completely. So for a quick fix limit the interval to one jiffie. This is not problematic in practice as alarmtimers are usually backed by an RTC for suspend which have 1 second resolution. It could be therefor argued that the resolution of this clock should be set to 1 second in general, but that's outside the scope of this fix. Signed-off-by:
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Thomas Gleixner authored
Andrey reported a alartimer related RCU stall while fuzzing the kernel with syzkaller. The reason for this is an overflow in ktime_add() which brings the resulting time into negative space and causes immediate expiry of the timer. The following rearm with a small interval does not bring the timer back into positive space due to the same issue. This results in a permanent firing alarmtimer which hogs the CPU. Use ktime_add_safe() instead which detects the overflow and clamps the result to KTIME_SEC_MAX. Reported-by:
Andrey Konovalov <andreyknvl@google.com> Signed-off-by:
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Christoph Hellwig authored
By moving the kernel side __SI_* defintions right next to the userspace ones we can kill the non-uapi versions of <asm/siginfo.h> include include/asm-generic/siginfo.h and untangle the unholy mess of includes. [ tglx: Removed uapi/asm/siginfo.h from m32r, microblaze, mn10300 and score ] Signed-off-by:
Christoph Hellwig <hch@lst.de> Signed-off-by:
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Christoph Hellwig authored
Having it in asm-generic/siginfo.h doesn't make any sense as it is in no way architecture specific. Move it to signal.h instead where several related functions already reside. Signed-off-by:
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Christoph Hellwig authored
Having it in asm-generic/siginfo.h doesn't make any sense as it is in no way architecture specific. Move it to posix-timers.h instead. Signed-off-by:
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Christoph Hellwig authored
Since ia64 defines __ARCH_SI_PREAMBLE_SIZE it can just use the generic copy_siginfo implementation, which is identical to the architecture specific one. With that support for HAVE_ARCH_COPY_SIGINFO can go away entirely. Signed-off-by:
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Christoph Hellwig authored
There is no need for the forward declaration of compat_siginfo provided here. We can't yet use the generic header as we need to pull in the sparc-specific version of the uapi <asm/siginfo.h>, but this prepares for removing the non-uapi <asm/siginfo.h> entirely. Signed-off-by:
"David S. Miller" <davem@davemloft.net> Signed-off-by:
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- 02 Jun, 2017 14 commits
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git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pmLinus Torvalds authored
Pull ACPI fixes from Rafael Wysocki: "These revert one more problematic commit related to the ACPI-based handling of laptop lids and make some unuseful error messages coming from ACPICA go away. Specifics: - Revert one more commit related to the ACPI-based handling of laptop lids that changed the default behavior on laptops that booted with closed lids and introduced a regression there (Benjamin Tissoires). - Add a missing acpi_put_table() to the code implementing the /sys/firmware/acpi/tables interface to prevent a counter in the ACPICA core from overflowing (Dan Williams). - Drop error messages printed by ACPICA on acpi_get_table() reference counting mismatches as they need not indicate real errors at this point (Lv Zheng)" * tag 'acpi-4.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: ACPICA: Tables: Fix regression introduced by a too early mechanism enabling Revert "ACPI / button: Change default behavior to lid_init_state=open" ACPI / sysfs: fix acpi_get_table() leak / acpi-sysfs denial of service -
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pmLinus Torvalds authored
Pull power management fixes from Rafael Wysocki: "These fix two bugs in error code paths in the cpufreq core and in the kirkwood-cpufreq driver. Specifics: - Make cpufreq_register_driver() return an error if the ->init() calls fail for all CPUs to prevent non-functional drivers from hanging around for no reason (David Arcari). - Make kirkwood-cpufreq check the return value of clk_prepare_enable() (which may fail) as appropriate (Arvind Yadav)" * tag 'pm-4.12-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: cpufreq: kirkwood-cpufreq:- Handle return value of clk_prepare_enable() cpufreq: cpufreq_register_driver() should return -ENODEV if init fails -
git://git.kernel.org/pub/scm/linux/kernel/git/tytso/randomLinus Torvalds authored
Pull /dev/random bug fix from Ted Ts'o: "Fix a race on architectures with prioritized interrupts (such as m68k) which can causes crashes in drivers/char/random.c:get_reg()" * tag 'random_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random: fix race in drivers/char/random.c:get_reg()
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Linus Torvalds authored
Merge misc fixes from Andrew Morton: "15 fixes" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: scripts/gdb: make lx-dmesg command work (reliably) mm: consider memblock reservations for deferred memory initialization sizing mm/hugetlb: report -EHWPOISON not -EFAULT when FOLL_HWPOISON is specified mlock: fix mlock count can not decrease in race condition mm/migrate: fix refcount handling when !hugepage_migration_supported() dax: fix race between colliding PMD & PTE entries mm: avoid spurious 'bad pmd' warning messages mm/page_alloc.c: make sure OOM victim can try allocations with no watermarks once pcmcia: remove left-over %Z format slub/memcg: cure the brainless abuse of sysfs attributes initramfs: fix disabling of initramfs (and its compression) mm: clarify why we want kmalloc before falling backto vmallock frv: declare jiffies to be located in the .data section include/linux/gfp.h: fix ___GFP_NOLOCKDEP value ksm: prevent crash after write_protect_page fails
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André Draszik authored
lx-dmesg needs access to the log_buf symbol from printk.c. Unfortunately, the symbol log_buf also exists in BPF's verifier.c and hence gdb can pick one or the other. If it happens to pick BPF's log_buf, lx-dmesg doesn't work: (gdb) lx-dmesg Python Exception <class 'gdb.MemoryError'> Cannot access memory at address 0x0: Error occurred in Python command: Cannot access memory at address 0x0 (gdb) p log_buf $15 = 0x0 Luckily, GDB has a way to deal with this, see https://sourceware.org/gdb/onlinedocs/gdb/Symbols.html (gdb) info variables ^log_buf$ All variables matching regular expression "^log_buf$": File <linux.git>/kernel/bpf/verifier.c: static char *log_buf; File <linux.git>/kernel/printk/printk.c: static char *log_buf; (gdb) p 'verifier.c'::log_buf $1 = 0x0 (gdb) p 'printk.c'::log_buf $2 = 0x811a6aa0 <__log_buf> "" (gdb) p &log_buf $3 = (char **) 0x8120fe40 <log_buf> (gdb) p &'verifier.c'::log_buf $4 = (char **) 0x8120fe40 <log_buf> (gdb) p &'printk.c'::log_buf $5 = (char **) 0x8048b7d0 <log_buf> By being explicit about the location of the symbol, we can make lx-dmesg work again. While at it, do the same for the other symbols we need from printk.c Link: http://lkml.kernel.org/r/20170526112222.3414-1-git@andred.netSigned-off-by:
André Draszik <git@andred.net> Tested-by:
Kieran Bingham <kieran@bingham.xyz> Acked-by:
Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Michal Hocko authored
We have seen an early OOM killer invocation on ppc64 systems with crashkernel=4096M: kthreadd invoked oom-killer: gfp_mask=0x16040c0(GFP_KERNEL|__GFP_COMP|__GFP_NOTRACK), nodemask=7, order=0, oom_score_adj=0 kthreadd cpuset=/ mems_allowed=7 CPU: 0 PID: 2 Comm: kthreadd Not tainted 4.4.68-1.gd7fe927-default #1 Call Trace: dump_stack+0xb0/0xf0 (unreliable) dump_header+0xb0/0x258 out_of_memory+0x5f0/0x640 __alloc_pages_nodemask+0xa8c/0xc80 kmem_getpages+0x84/0x1a0 fallback_alloc+0x2a4/0x320 kmem_cache_alloc_node+0xc0/0x2e0 copy_process.isra.25+0x260/0x1b30 _do_fork+0x94/0x470 kernel_thread+0x48/0x60 kthreadd+0x264/0x330 ret_from_kernel_thread+0x5c/0xa4 Mem-Info: active_anon:0 inactive_anon:0 isolated_anon:0 active_file:0 inactive_file:0 isolated_file:0 unevictable:0 dirty:0 writeback:0 unstable:0 slab_reclaimable:5 slab_unreclaimable:73 mapped:0 shmem:0 pagetables:0 bounce:0 free:0 free_pcp:0 free_cma:0 Node 7 DMA free:0kB min:0kB low:0kB high:0kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:52428800kB managed:110016kB mlocked:0kB dirty:0kB writeback:0kB mapped:0kB shmem:0kB slab_reclaimable:320kB slab_unreclaimable:4672kB kernel_stack:1152kB pagetables:0kB unstable:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? yes lowmem_reserve[]: 0 0 0 0 Node 7 DMA: 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB 0*8192kB 0*16384kB = 0kB 0 total pagecache pages 0 pages in swap cache Swap cache stats: add 0, delete 0, find 0/0 Free swap = 0kB Total swap = 0kB 819200 pages RAM 0 pages HighMem/MovableOnly 817481 pages reserved 0 pages cma reserved 0 pages hwpoisoned the reason is that the managed memory is too low (only 110MB) while the rest of the the 50GB is still waiting for the deferred intialization to be done. update_defer_init estimates the initial memoty to initialize to 2GB at least but it doesn't consider any memory allocated in that range. In this particular case we've had Reserving 4096MB of memory at 128MB for crashkernel (System RAM: 51200MB) so the low 2GB is mostly depleted. Fix this by considering memblock allocations in the initial static initialization estimation. Move the max_initialise to reset_deferred_meminit and implement a simple memblock_reserved_memory helper which iterates all reserved blocks and sums the size of all that start below the given address. The cumulative size is than added on top of the initial estimation. This is still not ideal because reset_deferred_meminit doesn't consider holes and so reservation might be above the initial estimation whihch we ignore but let's make the logic simpler until we really need to handle more complicated cases. Fixes: 3a80a7fa ("mm: meminit: initialise a subset of struct pages if CONFIG_DEFERRED_STRUCT_PAGE_INIT is set") Link: http://lkml.kernel.org/r/20170531104010.GI27783@dhcp22.suse.czSigned-off-by:
Michal Hocko <mhocko@suse.com> Acked-by:
Mel Gorman <mgorman@suse.de> Tested-by:
Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: <stable@vger.kernel.org> [4.2+] Signed-off-by:
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James Morse authored
KVM uses get_user_pages() to resolve its stage2 faults. KVM sets the FOLL_HWPOISON flag causing faultin_page() to return -EHWPOISON when it finds a VM_FAULT_HWPOISON. KVM handles these hwpoison pages as a special case. (check_user_page_hwpoison()) When huge pages are involved, this doesn't work so well. get_user_pages() calls follow_hugetlb_page(), which stops early if it receives VM_FAULT_HWPOISON from hugetlb_fault(), eventually returning -EFAULT to the caller. The step to map this to -EHWPOISON based on the FOLL_ flags is missing. The hwpoison special case is skipped, and -EFAULT is returned to user-space, causing Qemu or kvmtool to exit. Instead, move this VM_FAULT_ to errno mapping code into a header file and use it from faultin_page() and follow_hugetlb_page(). With this, KVM works as expected. This isn't a problem for arm64 today as we haven't enabled MEMORY_FAILURE, but I can't see any reason this doesn't happen on x86 too, so I think this should be a fix. This doesn't apply earlier than stable's v4.11.1 due to all sorts of cleanup. [james.morse@arm.com: add vm_fault_to_errno() call to faultin_page()] suggested. Link: http://lkml.kernel.org/r/20170525171035.16359-1-james.morse@arm.com [akpm@linux-foundation.org: coding-style fixes] Link: http://lkml.kernel.org/r/20170524160900.28786-1-james.morse@arm.comSigned-off-by:
James Morse <james.morse@arm.com> Acked-by:
Punit Agrawal <punit.agrawal@arm.com> Acked-by:
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: <stable@vger.kernel.org> [4.11.1+] Signed-off-by:
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Yisheng Xie authored
Kefeng reported that when running the follow test, the mlock count in meminfo will increase permanently: [1] testcase linux:~ # cat test_mlockal grep Mlocked /proc/meminfo for j in `seq 0 10` do for i in `seq 4 15` do ./p_mlockall >> log & done sleep 0.2 done # wait some time to let mlock counter decrease and 5s may not enough sleep 5 grep Mlocked /proc/meminfo linux:~ # cat p_mlockall.c #include <sys/mman.h> #include <stdlib.h> #include <stdio.h> #define SPACE_LEN 4096 int main(int argc, char ** argv) { int ret; void *adr = malloc(SPACE_LEN); if (!adr) return -1; ret = mlockall(MCL_CURRENT | MCL_FUTURE); printf("mlcokall ret = %d\n", ret); ret = munlockall(); printf("munlcokall ret = %d\n", ret); free(adr); return 0; } In __munlock_pagevec() we should decrement NR_MLOCK for each page where we clear the PageMlocked flag. Commit 1ebb7cc6 ("mm: munlock: batch NR_MLOCK zone state updates") has introduced a bug where we don't decrement NR_MLOCK for pages where we clear the flag, but fail to isolate them from the lru list (e.g. when the pages are on some other cpu's percpu pagevec). Since PageMlocked stays cleared, the NR_MLOCK accounting gets permanently disrupted by this. Fix it by counting the number of page whose PageMlock flag is cleared. Fixes: 1ebb7cc6 (" mm: munlock: batch NR_MLOCK zone state updates") Link: http://lkml.kernel.org/r/1495678405-54569-1-git-send-email-xieyisheng1@huawei.comSigned-off-by:Yisheng Xie <xieyisheng1@huawei.com> Reported-by:
Kefeng Wang <wangkefeng.wang@huawei.com> Tested-by:
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Punit Agrawal authored
On failing to migrate a page, soft_offline_huge_page() performs the necessary update to the hugepage ref-count. But when !hugepage_migration_supported() , unmap_and_move_hugepage() also decrements the page ref-count for the hugepage. The combined behaviour leaves the ref-count in an inconsistent state. This leads to soft lockups when running the overcommitted hugepage test from mce-tests suite. Soft offlining pfn 0x83ed600 at process virtual address 0x400000000000 soft offline: 0x83ed600: migration failed 1, type 1fffc00000008008 (uptodate|head) INFO: rcu_preempt detected stalls on CPUs/tasks: Tasks blocked on level-0 rcu_node (CPUs 0-7): P2715 (detected by 7, t=5254 jiffies, g=963, c=962, q=321) thugetlb_overco R running task 0 2715 2685 0x00000008 Call trace: dump_backtrace+0x0/0x268 show_stack+0x24/0x30 sched_show_task+0x134/0x180 rcu_print_detail_task_stall_rnp+0x54/0x7c rcu_check_callbacks+0xa74/0xb08 update_process_times+0x34/0x60 tick_sched_handle.isra.7+0x38/0x70 tick_sched_timer+0x4c/0x98 __hrtimer_run_queues+0xc0/0x300 hrtimer_interrupt+0xac/0x228 arch_timer_handler_phys+0x3c/0x50 handle_percpu_devid_irq+0x8c/0x290 generic_handle_irq+0x34/0x50 __handle_domain_irq+0x68/0xc0 gic_handle_irq+0x5c/0xb0 Address this by changing the putback_active_hugepage() in soft_offline_huge_page() to putback_movable_pages(). This only triggers on systems that enable memory failure handling (ARCH_SUPPORTS_MEMORY_FAILURE) but not hugepage migration (!ARCH_ENABLE_HUGEPAGE_MIGRATION). I imagine this wasn't triggered as there aren't many systems running this configuration. [akpm@linux-foundation.org: remove dead comment, per Naoya] Link: http://lkml.kernel.org/r/20170525135146.32011-1-punit.agrawal@arm.comReported-by:Manoj Iyer <manoj.iyer@canonical.com> Tested-by:
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Ross Zwisler authored
We currently have two related PMD vs PTE races in the DAX code. These can both be easily triggered by having two threads reading and writing simultaneously to the same private mapping, with the key being that private mapping reads can be handled with PMDs but private mapping writes are always handled with PTEs so that we can COW. Here is the first race: CPU 0 CPU 1 (private mapping write) __handle_mm_fault() create_huge_pmd() - FALLBACK handle_pte_fault() passes check for pmd_devmap() (private mapping read) __handle_mm_fault() create_huge_pmd() dax_iomap_pmd_fault() inserts PMD dax_iomap_pte_fault() does a PTE fault, but we already have a DAX PMD installed in our page tables at this spot. Here's the second race: CPU 0 CPU 1 (private mapping read) __handle_mm_fault() passes check for pmd_none() create_huge_pmd() dax_iomap_pmd_fault() inserts PMD (private mapping write) __handle_mm_fault() create_huge_pmd() - FALLBACK (private mapping read) __handle_mm_fault() passes check for pmd_none() create_huge_pmd() handle_pte_fault() dax_iomap_pte_fault() inserts PTE dax_iomap_pmd_fault() inserts PMD, but we already have a PTE at this spot. The core of the issue is that while there is isolation between faults to the same range in the DAX fault handlers via our DAX entry locking, there is no isolation between faults in the code in mm/memory.c. This means for instance that this code in __handle_mm_fault() can run: if (pmd_none(*vmf.pmd) && transparent_hugepage_enabled(vma)) { ret = create_huge_pmd(&vmf); But by the time we actually get to run the fault handler called by create_huge_pmd(), the PMD is no longer pmd_none() because a racing PTE fault has installed a normal PMD here as a parent. This is the cause of the 2nd race. The first race is similar - there is the following check in handle_pte_fault(): } else { /* See comment in pte_alloc_one_map() */ if (pmd_devmap(*vmf->pmd) || pmd_trans_unstable(vmf->pmd)) return 0; So if a pmd_devmap() PMD (a DAX PMD) has been installed at vmf->pmd, we will bail and retry the fault. This is correct, but there is nothing preventing the PMD from being installed after this check but before we actually get to the DAX PTE fault handlers. In my testing these races result in the following types of errors: BUG: Bad rss-counter state mm:ffff8800a817d280 idx:1 val:1 BUG: non-zero nr_ptes on freeing mm: 15 Fix this issue by having the DAX fault handlers verify that it is safe to continue their fault after they have taken an entry lock to block other racing faults. [ross.zwisler@linux.intel.com: improve fix for colliding PMD & PTE entries] Link: http://lkml.kernel.org/r/20170526195932.32178-1-ross.zwisler@linux.intel.com Link: http://lkml.kernel.org/r/20170522215749.23516-2-ross.zwisler@linux.intel.comSigned-off-by:Ross Zwisler <ross.zwisler@linux.intel.com> Reported-by:
Pawel Lebioda <pawel.lebioda@intel.com> Reviewed-by:
Jan Kara <jack@suse.cz> Cc: "Darrick J. Wong" <darrick.wong@oracle.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com> Cc: Pawel Lebioda <pawel.lebioda@intel.com> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Xiong Zhou <xzhou@redhat.com> Cc: Eryu Guan <eguan@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by:
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Ross Zwisler authored
When the pmd_devmap() checks were added by 5c7fb56e ("mm, dax: dax-pmd vs thp-pmd vs hugetlbfs-pmd") to add better support for DAX huge pages, they were all added to the end of if() statements after existing pmd_trans_huge() checks. So, things like: - if (pmd_trans_huge(*pmd)) + if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) When further checks were added after pmd_trans_unstable() checks by commit 7267ec00 ("mm: postpone page table allocation until we have page to map") they were also added at the end of the conditional: + if (pmd_trans_unstable(fe->pmd) || pmd_devmap(*fe->pmd)) This ordering is fine for pmd_trans_huge(), but doesn't work for pmd_trans_unstable(). This is because DAX huge pages trip the bad_pmd() check inside of pmd_none_or_trans_huge_or_clear_bad() (called by pmd_trans_unstable()), which prints out a warning and returns 1. So, we do end up doing the right thing, but only after spamming dmesg with suspicious looking messages: mm/pgtable-generic.c:39: bad pmd ffff8808daa49b88(84000001006000a5) Reorder these checks in a helper so that pmd_devmap() is checked first, avoiding the error messages, and add a comment explaining why the ordering is important. Fixes: commit 7267ec00 ("mm: postpone page table allocation until we have page to map") Link: http://lkml.kernel.org/r/20170522215749.23516-1-ross.zwisler@linux.intel.comSigned-off-by:
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Tetsuo Handa authored
Roman Gushchin has reported that the OOM killer can trivially selects next OOM victim when a thread doing memory allocation from page fault path was selected as first OOM victim. allocate invoked oom-killer: gfp_mask=0x14280ca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO), nodemask=(null), order=0, oom_score_adj=0 allocate cpuset=/ mems_allowed=0 CPU: 1 PID: 492 Comm: allocate Not tainted 4.12.0-rc1-mm1+ #181 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 Call Trace: oom_kill_process+0x219/0x3e0 out_of_memory+0x11d/0x480 __alloc_pages_slowpath+0xc84/0xd40 __alloc_pages_nodemask+0x245/0x260 alloc_pages_vma+0xa2/0x270 __handle_mm_fault+0xca9/0x10c0 handle_mm_fault+0xf3/0x210 __do_page_fault+0x240/0x4e0 trace_do_page_fault+0x37/0xe0 do_async_page_fault+0x19/0x70 async_page_fault+0x28/0x30 ... Out of memory: Kill process 492 (allocate) score 899 or sacrifice child Killed process 492 (allocate) total-vm:2052368kB, anon-rss:1894576kB, file-rss:4kB, shmem-rss:0kB allocate: page allocation failure: order:0, mode:0x14280ca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO), nodemask=(null) allocate cpuset=/ mems_allowed=0 CPU: 1 PID: 492 Comm: allocate Not tainted 4.12.0-rc1-mm1+ #181 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 Call Trace: __alloc_pages_slowpath+0xd32/0xd40 __alloc_pages_nodemask+0x245/0x260 alloc_pages_vma+0xa2/0x270 __handle_mm_fault+0xca9/0x10c0 handle_mm_fault+0xf3/0x210 __do_page_fault+0x240/0x4e0 trace_do_page_fault+0x37/0xe0 do_async_page_fault+0x19/0x70 async_page_fault+0x28/0x30 ... oom_reaper: reaped process 492 (allocate), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB ... allocate invoked oom-killer: gfp_mask=0x0(), nodemask=(null), order=0, oom_score_adj=0 allocate cpuset=/ mems_allowed=0 CPU: 1 PID: 492 Comm: allocate Not tainted 4.12.0-rc1-mm1+ #181 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014 Call Trace: oom_kill_process+0x219/0x3e0 out_of_memory+0x11d/0x480 pagefault_out_of_memory+0x68/0x80 mm_fault_error+0x8f/0x190 ? handle_mm_fault+0xf3/0x210 __do_page_fault+0x4b2/0x4e0 trace_do_page_fault+0x37/0xe0 do_async_page_fault+0x19/0x70 async_page_fault+0x28/0x30 ... Out of memory: Kill process 233 (firewalld) score 10 or sacrifice child Killed process 233 (firewalld) total-vm:246076kB, anon-rss:20956kB, file-rss:0kB, shmem-rss:0kB There is a race window that the OOM reaper completes reclaiming the first victim's memory while nothing but mutex_trylock() prevents the first victim from calling out_of_memory() from pagefault_out_of_memory() after memory allocation for page fault path failed due to being selected as an OOM victim. This is a side effect of commit 9a67f648 ("mm: consolidate GFP_NOFAIL checks in the allocator slowpath") because that commit silently changed the behavior from /* Avoid allocations with no watermarks from looping endlessly */ to /* * Give up allocations without trying memory reserves if selected * as an OOM victim */ in __alloc_pages_slowpath() by moving the location to check TIF_MEMDIE flag. I have noticed this change but I didn't post a patch because I thought it is an acceptable change other than noise by warn_alloc() because !__GFP_NOFAIL allocations are allowed to fail. But we overlooked that failing memory allocation from page fault path makes difference due to the race window explained above. While it might be possible to add a check to pagefault_out_of_memory() that prevents the first victim from calling out_of_memory() or remove out_of_memory() from pagefault_out_of_memory(), changing pagefault_out_of_memory() does not suppress noise by warn_alloc() when allocating thread was selected as an OOM victim. There is little point with printing similar backtraces and memory information from both out_of_memory() and warn_alloc(). Instead, if we guarantee that current thread can try allocations with no watermarks once when current thread looping inside __alloc_pages_slowpath() was selected as an OOM victim, we can follow "who can use memory reserves" rules and suppress noise by warn_alloc() and prevent memory allocations from page fault path from calling pagefault_out_of_memory(). If we take the comment literally, this patch would do - if (test_thread_flag(TIF_MEMDIE)) - goto nopage; + if (alloc_flags == ALLOC_NO_WATERMARKS || (gfp_mask & __GFP_NOMEMALLOC)) + goto nopage; because gfp_pfmemalloc_allowed() returns false if __GFP_NOMEMALLOC is given. But if I recall correctly (I couldn't find the message), the condition is meant to apply to only OOM victims despite the comment. Therefore, this patch preserves TIF_MEMDIE check. Fixes: 9a67f648 ("mm: consolidate GFP_NOFAIL checks in the allocator slowpath") Link: http://lkml.kernel.org/r/201705192112.IAF69238.OQOHSJLFOFFMtV@I-love.SAKURA.ne.jpSigned-off-by:Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reported-by:
Roman Gushchin <guro@fb.com> Tested-by:
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Nicolas Iooss authored
Commit 5b5e0928 ("lib/vsprintf.c: remove %Z support") removed some usages of format %Z but forgot "%.2Zx". This makes clang 4.0 reports a -Wformat-extra-args warning because it does not know about %Z. Replace %Z with %z. Link: http://lkml.kernel.org/r/20170520090946.22562-1-nicolas.iooss_linux@m4x.orgSigned-off-by:
Nicolas Iooss <nicolas.iooss_linux@m4x.org> Cc: Harald Welte <laforge@gnumonks.org> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: <stable@vger.kernel.org> [4.11+] Signed-off-by:
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Thomas Gleixner authored
memcg_propagate_slab_attrs() abuses the sysfs attribute file functions to propagate settings from the root kmem_cache to a newly created kmem_cache. It does that with: attr->show(root, buf); attr->store(new, buf, strlen(bug); Aside of being a lazy and absurd hackery this is broken because it does not check the return value of the show() function. Some of the show() functions return 0 w/o touching the buffer. That means in such a case the store function is called with the stale content of the previous show(). That causes nonsense like invoking kmem_cache_shrink() on a newly created kmem_cache. In the worst case it would cause handing in an uninitialized buffer. This should be rewritten proper by adding a propagate() callback to those slub_attributes which must be propagated and avoid that insane conversion to and from ASCII, but that's too large for a hot fix. Check at least the return value of the show() function, so calling store() with stale content is prevented. Steven said: "It can cause a deadlock with get_online_cpus() that has been uncovered by recent cpu hotplug and lockdep changes that Thomas and Peter have been doing. Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(cpu_hotplug.lock); lock(slab_mutex); lock(cpu_hotplug.lock); lock(slab_mutex); *** DEADLOCK ***" Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1705201244540.2255@nanosSigned-off-by:Steven Rostedt <rostedt@goodmis.org> Acked-by:
David Rientjes <rientjes@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: <stable@vger.kernel.org> Signed-off-by:
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