WSL2-Linux-Kernel/mm
zhong jiang 5b398e416e mm,ksm: fix endless looping in allocating memory when ksm enable
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>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-09-28 16:19:01 -07:00
..
kasan kasan: remove the unnecessary WARN_ONCE from quarantine.c 2016-08-11 16:58:14 -07:00
Kconfig mm: clarify COMPACTION Kconfig text 2016-08-26 17:39:35 -07:00
Kconfig.debug mm/page_ref: add tracepoint to track down page reference manipulation 2016-03-17 15:09:34 -07:00
Makefile Implements HARDENED_USERCOPY verification of copy_to_user/copy_from_user 2016-08-08 14:48:14 -07:00
backing-dev.c block: fix bdi vs gendisk lifetime mismatch 2016-08-04 14:19:16 -06:00
balloon_compaction.c mm: balloon: use general non-lru movable page feature 2016-07-26 16:19:19 -07:00
bootmem.c mm: convert printk(KERN_<LEVEL> to pr_<level> 2016-03-17 15:09:34 -07:00
cleancache.c cleancache: constify cleancache_ops structure 2016-01-27 09:09:57 -05:00
cma.c mm/cma: silence warnings due to max() usage 2016-05-27 14:49:37 -07:00
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: simplify contended compaction handling 2016-07-28 16:07:41 -07:00
debug.c mm: avoid endless recursion in dump_page() 2016-09-19 15:36:16 -07:00
debug_page_ref.c mm/page_ref: add tracepoint to track down page reference manipulation 2016-03-17 15:09:34 -07:00
dmapool.c mm: convert printk(KERN_<LEVEL> to pr_<level> 2016-03-17 15:09:34 -07:00
early_ioremap.c mm/early_ioremap: use offset_in_page macro 2015-11-05 19:34:48 -08:00
fadvise.c mm/fadvise.c: do not discard partial pages with POSIX_FADV_DONTNEED 2016-06-09 14:23:11 -07:00
failslab.c mm: fault-inject take over bootstrap kmem_cache check 2016-03-15 16:55:16 -07:00
filemap.c block/mm: make bdev_ops->rw_page() take a bool for read/write 2016-08-07 14:41:02 -06:00
frame_vector.c mm/gup: Switch all callers of get_user_pages() to not pass tsk/mm 2016-02-16 10:11:12 +01:00
frontswap.c mm, frontswap: convert frontswap_enabled to static key 2016-07-26 16:19:19 -07:00
gup.c - ARM: GICv3 ITS emulation and various fixes. Removal of the old 2016-08-02 16:11:27 -04:00
highmem.c mm/highmem: make nr_free_highpages() handles all highmem zones by itself 2016-05-19 19:12:14 -07:00
huge_memory.c mm: check VMA flags to avoid invalid PROT_NONE NUMA balancing 2016-09-25 15:43:42 -07:00
hugetlb.c mm/hugetlb: fix incorrect hugepages count during mem hotplug 2016-08-11 16:58:13 -07:00
hugetlb_cgroup.c mm, hugetlb_cgroup: round limit_in_bytes down to hugepage size 2016-05-20 17:58:30 -07:00
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, compaction: simplify contended compaction handling 2016-07-28 16:07:41 -07:00
interval_tree.c mm: replace vma->sharead.linear with vma->shared 2015-02-10 14:30:31 -08:00
khugepaged.c mm, thp: fix leaking mapped pte in __collapse_huge_page_swapin() 2016-09-19 15:36:16 -07:00
kmemcheck.c mm: convert printk(KERN_<LEVEL> to pr_<level> 2016-03-17 15:09:34 -07:00
kmemleak-test.c mm: convert printk(KERN_<LEVEL> to pr_<level> 2016-03-17 15:09:34 -07:00
kmemleak.c kmemleak: don't hang if user disables scanning early 2016-07-28 16:07:41 -07:00
ksm.c mm,ksm: fix endless looping in allocating memory when ksm enable 2016-09-28 16:19:01 -07:00
list_lru.c mm: memcontrol: move kmem accounting code to CONFIG_MEMCG 2016-01-20 17:09:18 -08:00
maccess.c x86: remove more uaccess_32.h complexity 2016-05-22 17:21:27 -07:00
madvise.c mm: make mmap_sem for write waits killable for mm syscalls 2016-05-23 17:04:14 -07:00
memblock.c mm/memblock.c: fix NULL dereference error 2016-08-04 20:02:09 -04:00
memcontrol.c mm: memcontrol: make per-cpu charge cache IRQ-safe for socket accounting 2016-09-19 15:36:17 -07:00
memory-failure.c mm: hwpoison: remove incorrect comments 2016-07-28 16:07:41 -07:00
memory.c mm: check VMA flags to avoid invalid PROT_NONE NUMA balancing 2016-09-25 15:43:42 -07:00
memory_hotplug.c mem-hotplug: don't clear the only node in new_node_page() 2016-09-19 15:36:16 -07:00
mempolicy.c mm, mempolicy: task->mempolicy must be NULL before dropping final reference 2016-09-01 17:52:01 -07:00
mempool.c Revert "mm, mempool: only set __GFP_NOMEMALLOC if there are free elements" 2016-07-28 16:07:41 -07:00
memtest.c memtest: remove unused header files 2015-09-08 15:35:28 -07:00
migrate.c mm, thp: remove __GFP_NORETRY from khugepaged and madvised allocations 2016-07-28 16:07:41 -07:00
mincore.c mm, fs: remove remaining PAGE_CACHE_* and page_cache_{get,release} usage 2016-04-04 10:41:08 -07:00
mlock.c mm, vmscan: move LRU lists to node 2016-07-28 16:07:41 -07:00
mm_init.c mm: convert printk(KERN_<LEVEL> to pr_<level> 2016-03-17 15:09:34 -07:00
mmap.c mm: refuse wrapped vm_brk requests 2016-08-02 19:35:15 -04:00
mmu_context.c mm/mmu_context, sched/core: Fix mmu_context.h assumption 2016-04-28 11:44:19 +02:00
mmu_notifier.c fix Christoph's email addresses 2016-03-17 15:09:34 -07:00
mmzone.c mm, page_alloc: inline the fast path of the zonelist iterator 2016-05-19 19:12:14 -07:00
mprotect.c mm: thp: check pmd_trans_unstable() after split_huge_pmd() 2016-07-26 16:19:19 -07:00
mremap.c mm: thp: check pmd_trans_unstable() after split_huge_pmd() 2016-07-26 16:19:19 -07:00
msync.c mm/msync: use offset_in_page macro 2015-11-05 19:34:48 -08:00
nobootmem.c mm: convert printk(KERN_<LEVEL> to pr_<level> 2016-03-17 15:09:34 -07:00
nommu.c mm: introduce fault_env 2016-07-26 16:19:19 -07:00
oom_kill.c mm, oom: fix uninitialized ret in task_will_free_mem() 2016-08-11 16:58:14 -07:00
page-writeback.c mm: remove reclaim and compaction retry approximations 2016-07-28 16:07:41 -07:00
page_alloc.c mm, vmscan: only allocate and reclaim from zones with pages managed by the buddy allocator 2016-09-01 17:52:01 -07:00
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: use early_pfn_to_nid in page_ext_init 2016-05-27 14:49:37 -07:00
page_idle.c mm, vmscan: move lru_lock to the node 2016-07-28 16:07:41 -07:00
page_io.c mm: fix the page_swap_info() BUG_ON check 2016-09-19 15:36:17 -07:00
page_isolation.c mm/page_isolation: clean up confused code 2016-07-26 16:19:19 -07:00
page_owner.c mm/page_owner: use stackdepot to store stacktrace 2016-07-26 16:19:19 -07:00
page_poison.c mm: check the return value of lookup_page_ext for all call sites 2016-06-03 15:06:22 -07:00
pagewalk.c thp: rename split_huge_page_pmd() to split_huge_pmd() 2016-01-15 17:56:32 -08:00
percpu-km.c mm: percpu: use pr_fmt to prefix output 2016-03-17 15:09:34 -07:00
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 2016-05-25 11:48:25 -04:00
pgtable-generic.c mm/thp/migration: switch from flush_tlb_range to flush_pmd_tlb_range 2016-03-17 15:09:34 -07:00
process_vm_access.c mm/gup: Introduce get_user_pages_remote() 2016-02-16 10:04:09 +01:00
quicklist.c fix Christoph's email addresses 2016-03-17 15:09:34 -07:00
readahead.c mm: silently skip readahead for DAX inodes 2016-08-26 17:39:35 -07:00
rmap.c rmap: fix compound check logic in page_remove_file_rmap 2016-08-10 16:40:56 -07:00
shmem.c huge tmpfs: fix Committed_AS leak 2016-09-24 11:20:01 -07:00
slab.c Implements HARDENED_USERCOPY verification of copy_to_user/copy_from_user 2016-08-08 14:48:14 -07:00
slab.h mm, kasan: switch SLUB to stackdepot, enable memory quarantine for SLUB 2016-07-28 16:07:41 -07:00
slab_common.c mm: charge/uncharge kmemcg from generic page allocator paths 2016-07-26 16:19:19 -07:00
slob.c mm: slab: free kmem_cache_node after destroy sysfs file 2016-02-18 16:23:24 -08:00
slub.c mm/slub.c: run free_partial() outside of the kmem_cache_node->list_lock 2016-08-10 16:40:56 -07:00
sparse-vmemmap.c treewide: replace obsolete _refok by __ref 2016-08-02 17:31:41 -04:00
sparse.c treewide: replace obsolete _refok by __ref 2016-08-02 17:31:41 -04:00
swap.c mm, pagevec: release/reacquire lru_lock on pgdat change 2016-07-28 16:07:41 -07:00
swap_cgroup.c mm: convert printk(KERN_<LEVEL> to pr_<level> 2016-03-17 15:09:34 -07:00
swap_state.c mm: move most file-based accounting to the node 2016-07-28 16:07:41 -07:00
swapfile.c mm: fix the page_swap_info() BUG_ON check 2016-09-19 15:36:17 -07:00
truncate.c truncate: handle file thp 2016-07-26 16:19:19 -07:00
usercopy.c mm: usercopy: Check for module addresses 2016-09-20 16:07:39 -07:00
userfaultfd.c mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros 2016-04-04 10:41:08 -07:00
util.c mm: move most file-based accounting to the node 2016-07-28 16:07:41 -07:00
vmacache.c mm/vmacache: inline vmacache_valid_mm() 2015-11-05 19:34:48 -08:00
vmalloc.c mm: charge/uncharge kmemcg from generic page allocator paths 2016-07-26 16:19:19 -07:00
vmpressure.c mm/vmpressure.c: fix subtree pressure detection 2016-02-03 08:28:43 -08:00
vmscan.c mm: delete unnecessary and unsafe init_tlb_ubc() 2016-09-24 11:20:01 -07:00
vmstat.c mm: remove reclaim and compaction retry approximations 2016-07-28 16:07:41 -07:00
workingset.c mm, workingset: make working set detection node-aware 2016-07-28 16:07:41 -07:00
z3fold.c mm/z3fold.c: avoid modifying HEADLESS page and minor cleanup 2016-06-03 16:02:55 -07:00
zbud.c mm/zbud.c: use list_last_entry() instead of list_tail_entry() 2016-01-15 11:40:52 -08:00
zpool.c mm: zsmalloc: constify struct zs_pool name 2015-11-06 17:50:42 -08:00
zsmalloc.c zsmalloc: Delete an unnecessary check before the function call "iput" 2016-07-28 16:07:41 -07:00
zswap.c mm/zswap: use workqueue to destroy pool 2016-05-20 17:58:30 -07:00