zhong jiang a2fc10c36f mm,ksm: fix endless looping in allocating memory when ksm enable ... commit 5b398e416e880159fe55eefd93c6588fa072cd66 upstream. I hit the following hung task when runing a OOM LTP test case with 4.1 kernel. Call trace: [<ffffffc000086a88>] __switch_to+0x74/0x8c [<ffffffc000a1bae0>] __schedule+0x23c/0x7bc [<ffffffc000a1c09c>] schedule+0x3c/0x94 [<ffffffc000a1eb84>] rwsem_down_write_failed+0x214/0x350 [<ffffffc000a1e32c>] down_write+0x64/0x80 [<ffffffc00021f794>] __ksm_exit+0x90/0x19c [<ffffffc0000be650>] mmput+0x118/0x11c [<ffffffc0000c3ec4>] do_exit+0x2dc/0xa74 [<ffffffc0000c46f8>] do_group_exit+0x4c/0xe4 [<ffffffc0000d0f34>] get_signal+0x444/0x5e0 [<ffffffc000089fcc>] do_signal+0x1d8/0x450 [<ffffffc00008a35c>] do_notify_resume+0x70/0x78 The oom victim cannot terminate because it needs to take mmap_sem for write while the lock is held by ksmd for read which loops in the page allocator ksm_do_scan scan_get_next_rmap_item down_read get_next_rmap_item alloc_rmap_item #ksmd will loop permanently. There is no way forward because the oom victim cannot release any memory in 4.1 based kernel. Since 4.6 we have the oom reaper which would solve this problem because it would release the memory asynchronously. Nevertheless we can relax alloc_rmap_item requirements and use __GFP_NORETRY because the allocation failure is acceptable as ksm_do_scan would just retry later after the lock got dropped. Such a patch would be also easy to backport to older stable kernels which do not have oom_reaper. While we are at it add GFP_NOWARN so the admin doesn't have to be alarmed by the allocation failure. Link: http://lkml.kernel.org/r/1474165570-44398-1-git-send-email-zhongjiang@huawei.com Signed-off-by: zhong jiang <zhongjiang@huawei.com> Suggested-by: Hugh Dickins <hughd@google.com> Suggested-by: Michal Hocko <mhocko@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2016-10-07 15:23:40 +02:00
..
kasan	kasan: fix kmemleak false-positive in kasan_module_alloc()	2015-11-20 16:17:32 -08:00
backing-dev.c	block: fix bdi vs gendisk lifetime mismatch	2016-08-20 18:09:24 +02:00
balloon_compaction.c	virtio_balloon: fix race between migration and ballooning	2016-03-03 15:07:18 -08:00
bootmem.c	bootmem: avoid freeing to bootmem after bootmem is done	2015-09-08 15:35:28 -07:00
cleancache.c	cleancache: remove limit on the number of cleancache enabled filesystems	2015-04-14 16:49:03 -07:00
cma.c	mm/cma.c: suppress warning	2015-11-05 19:34:48 -08:00
cma.h	mm: cma: mark cma_bitmap_maxno() inline in header	2015-08-14 15:56:32 -07:00
cma_debug.c	mm/cma_debug: correct size input to bitmap function	2015-07-17 16:39:54 -07:00
compaction.c	mm, compaction: prevent VM_BUG_ON when terminating freeing scanner	2016-08-10 11:49:25 +02:00
debug-pagealloc.c	mm/debug-pagealloc: make debug-pagealloc boottime configurable	2014-12-13 12:42:48 -08:00
debug.c	mm: make compound_head() robust	2015-11-06 17:50:42 -08:00
dmapool.c	mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd	2015-11-06 17:50:42 -08:00
early_ioremap.c	mm/early_ioremap: use offset_in_page macro	2015-11-05 19:34:48 -08:00
fadvise.c	writeback: implement and use inode_congested()	2015-06-02 08:33:35 -06:00
failslab.c	mm, page_alloc: rename __GFP_WAIT to __GFP_RECLAIM	2015-11-06 17:50:42 -08:00
filemap.c	mm, fs: introduce mapping_gfp_constraint()	2015-11-06 17:50:42 -08:00
frame_vector.c	mm: fix docbook comment for get_vaddr_frames()	2015-11-05 19:34:48 -08:00
frontswap.c	frontswap: allow multiple backends	2015-06-24 17:49:45 -07:00
gup.c	mm: introduce VM_LOCKONFAULT	2015-11-05 19:34:48 -08:00
highmem.c	mm/highmem: make kmap cache coloring aware	2014-08-06 18:01:22 -07:00
huge_memory.c	mm/huge_memory: replace VM_NO_THP VM_BUG_ON with actual VMA check	2016-05-04 14:48:49 -07:00
hugetlb.c	hugetlb: fix nr_pmds accounting with shared page tables	2016-09-07 08:32:35 +02:00
hugetlb_cgroup.c	mm: make compound_head() robust	2015-11-06 17:50:42 -08:00
hwpoison-inject.c	hwpoison: use page_cgroup_ino for filtering by memcg	2015-09-10 13:29:01 -07:00
init-mm.c
internal.h	mm, sl[au]b: add __GFP_ATOMIC to the GFP reclaim mask	2016-08-10 11:49:25 +02:00
interval_tree.c	mm: replace vma->sharead.linear with vma->shared	2015-02-10 14:30:31 -08:00
Kconfig	mm: make compound_head() robust	2015-11-06 17:50:42 -08:00
Kconfig.debug	mm/debug_pagealloc: remove obsolete Kconfig options	2015-01-08 15:10:52 -08:00
kmemcheck.c	mm/slab_common: move kmem_cache definition to internal header	2014-10-09 22:25:50 -04:00
kmemleak-test.c	mm/kmemleak-test.c: use pr_fmt for logging	2014-06-06 16:08:18 -07:00
kmemleak.c	mm/kmemleak.c: remove unneeded initialization of object to NULL	2015-11-05 19:34:48 -08:00
ksm.c	mm,ksm: fix endless looping in allocating memory when ksm enable	2016-10-07 15:23:40 +02:00
list_lru.c	memcg: simplify and inline __mem_cgroup_from_kmem	2015-11-05 19:34:48 -08:00
maccess.c	mm/maccess.c: actually return -EFAULT from strncpy_from_unsafe	2015-11-05 19:34:48 -08:00
madvise.c	mm: madvise allow remove operation for hugetlbfs	2015-09-08 15:35:28 -07:00
Makefile	media updates for v4.3-rc1	2015-09-11 16:42:39 -07:00
memblock.c	mm/memblock: make memblock_remove_range() static	2015-11-05 19:34:48 -08:00
memcontrol.c	mm: memcontrol: fix memcg id ref counter on swap charge move	2016-08-16 09:30:51 +02:00
memory-failure.c	mm: soft-offline: check return value in second __get_any_page() call	2016-02-25 12:01:21 -08:00
memory.c	numa: fix /proc/<pid>/numa_maps for THP	2016-05-04 14:48:49 -07:00
memory_hotplug.c	mm/memory_hotplug.c: check for missing sections in test_pages_in_a_zone()	2015-12-29 17:45:49 -08:00
mempolicy.c	mm: rename alloc_pages_exact_node() to __alloc_pages_node()	2015-09-08 15:35:28 -07:00
mempool.c	mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd	2015-11-06 17:50:42 -08:00
memtest.c	memtest: remove unused header files	2015-09-08 15:35:28 -07:00
migrate.c	mm: Export migrate_page_move_mapping and migrate_page_copy	2016-07-27 09:47:31 -07:00
mincore.c	mm/mincore: use offset_in_page macro	2015-11-05 19:34:48 -08:00
mlock.c	mm: fix mlock accouting	2016-02-25 12:01:21 -08:00
mm_init.c	mm: meminit: remove mminit_verify_page_links	2015-06-30 19:44:56 -07:00
mmap.c	mm: fix regression in remap_file_pages() emulation	2016-02-25 12:01:21 -08:00
mmu_context.c
mmu_notifier.c	mmu-notifier: add clear_young callback	2015-09-10 13:29:01 -07:00
mmzone.c	mm: microoptimize zonelist operations	2015-02-11 17:06:02 -08:00
mprotect.c	userfaultfd: teach vma_merge to merge across vma->vm_userfaultfd_ctx	2015-09-04 16:54:41 -07:00
mremap.c	mm/mremap: use offset_in_page macro	2015-11-05 19:34:48 -08:00
msync.c	mm/msync: use offset_in_page macro	2015-11-05 19:34:48 -08:00
nobootmem.c	mm: page_alloc: pass PFN to __free_pages_bootmem	2015-06-30 19:44:55 -07:00
nommu.c	mm/nommu.c: drop unlikely inside BUG_ON()	2015-11-05 19:34:48 -08:00
oom_kill.c	mm/oom_kill.c: avoid attempting to kill init sharing same memory	2015-12-12 10:15:34 -08:00
page-writeback.c	writeback: use higher precision calculation in domain_dirty_limits()	2016-07-27 09:47:29 -07:00
page_alloc.c	mm, meminit: ensure node is online before checking whether pages are uninitialised	2016-08-10 11:49:25 +02:00
page_counter.c	mm: page_counter: let page_counter_try_charge() return bool	2015-11-05 19:34:48 -08:00
page_ext.c	mm: introduce idle page tracking	2015-09-10 13:29:01 -07:00
page_idle.c	mm: introduce idle page tracking	2015-09-10 13:29:01 -07:00
page_io.c	fs: use helper bio_add_page() instead of open coding on bi_io_vec	2015-08-13 12:32:00 -06:00
page_isolation.c	mm: fix invalid node in alloc_migrate_target()	2016-04-20 15:41:53 +09:00
page_owner.c	mm/page_owner: set correct gfp_mask on page_owner	2015-07-17 16:39:54 -07:00
pagewalk.c	mm/pagewalk.c: prevent positive return value of walk_page_test() from being passed to callers	2015-03-25 16:20:30 -07:00
percpu-km.c	percpu: implmeent pcpu_nr_empty_pop_pages and chunk->nr_populated	2014-09-02 14:46:05 -04:00
percpu-vm.c	percpu: move region iterations out of pcpu_[de]populate_chunk()	2014-09-02 14:46:02 -04:00
percpu.c	percpu: fix synchronization between synchronous map extension and chunk destruction	2016-07-27 09:47:33 -07:00
pgtable-generic.c	mm,thp: khugepaged: call pte flush at the time of collapse	2016-02-25 12:01:23 -08:00
process_vm_access.c	ptrace: use fsuid, fsgid, effective creds for fs access checks	2016-02-25 12:01:16 -08:00
quicklist.c
readahead.c	mm, fs: introduce mapping_gfp_constraint()	2015-11-06 17:50:42 -08:00
rmap.c	mm: page migration use migration entry for swapcache too	2015-11-05 19:34:48 -08:00
shmem.c	tmpfs: fix regression hang in fallocate undo	2016-07-27 09:47:40 -07:00
slab.c	slab/slub: adjust kmem_cache_alloc_bulk API	2015-11-22 11:58:44 -08:00
slab.h	slab/slub: adjust kmem_cache_alloc_bulk API	2015-11-22 11:58:44 -08:00
slab_common.c	mm: memcontrol: fix cgroup creation failure after many small jobs	2016-08-16 09:30:51 +02:00
slob.c	slab/slub: adjust kmem_cache_alloc_bulk API	2015-11-22 11:58:44 -08:00
slub.c	slub: clean up code for kmem cgroup support to kmem_cache_free_bulk	2016-05-04 14:48:49 -07:00
sparse-vmemmap.c
sparse.c
swap.c	mm: make compound_head() robust	2015-11-06 17:50:42 -08:00
swap_cgroup.c	mm: page_cgroup: rename file to mm/swap_cgroup.c	2014-12-10 17:41:09 -08:00
swap_state.c	mm: swap: zswap: maybe_preload & refactoring	2015-09-08 15:35:28 -07:00
swapfile.c	mm: /proc/pid/smaps:: show proportional swap share of the mapping	2015-09-08 15:35:28 -07:00
truncate.c	memcg: add per cgroup dirty page accounting	2015-06-02 08:33:33 -06:00
userfaultfd.c	userfaultfd: avoid mmap_sem read recursion in mcopy_atomic	2015-09-04 16:54:41 -07:00
util.c	proc: revert /proc/<pid>/maps [stack:TID] annotation	2016-09-15 08:27:46 +02:00
vmacache.c	mm/vmacache: inline vmacache_valid_mm()	2015-11-05 19:34:48 -08:00
vmalloc.c	mm: vmalloc: don't remove inexistent guard hole in remove_vm_area()	2015-11-20 16:17:32 -08:00
vmpressure.c	mm/vmpressure.c: fix race in vmpressure_work_fn()	2014-12-02 17:32:07 -08:00
vmscan.c	mm: delete unnecessary and unsafe init_tlb_ubc()	2016-09-30 10:18:38 +02:00
vmstat.c	vmstat: allocate vmstat_wq before it is used	2016-01-08 23:47:54 -08:00
workingset.c	list_lru: add helpers to isolate items	2015-02-12 18:54:10 -08:00
zbud.c	mm: zsmalloc: constify struct zs_pool name	2015-11-06 17:50:42 -08:00
zpool.c	mm: zsmalloc: constify struct zs_pool name	2015-11-06 17:50:42 -08:00
zsmalloc.c	zsmalloc: fix zs_can_compact() integer overflow	2016-05-18 17:06:44 -07:00
zswap.c	mm/zswap: provide unique zpool name	2016-05-11 11:21:14 +02:00