WSL2-Linux-Kernel/mm
David Rientjes 2270dfcc4b mm, oom: fix concurrent munlock and oom reaper unmap, v3
commit 27ae357fa8 upstream.

Since exit_mmap() is done without the protection of mm->mmap_sem, it is
possible for the oom reaper to concurrently operate on an mm until
MMF_OOM_SKIP is set.

This allows munlock_vma_pages_all() to concurrently run while the oom
reaper is operating on a vma.  Since munlock_vma_pages_range() depends
on clearing VM_LOCKED from vm_flags before actually doing the munlock to
determine if any other vmas are locking the same memory, the check for
VM_LOCKED in the oom reaper is racy.

This is especially noticeable on architectures such as powerpc where
clearing a huge pmd requires serialize_against_pte_lookup().  If the pmd
is zapped by the oom reaper during follow_page_mask() after the check
for pmd_none() is bypassed, this ends up deferencing a NULL ptl or a
kernel oops.

Fix this by manually freeing all possible memory from the mm before
doing the munlock and then setting MMF_OOM_SKIP.  The oom reaper can not
run on the mm anymore so the munlock is safe to do in exit_mmap().  It
also matches the logic that the oom reaper currently uses for
determining when to set MMF_OOM_SKIP itself, so there's no new risk of
excessive oom killing.

This issue fixes CVE-2018-1000200.

Link: http://lkml.kernel.org/r/alpine.DEB.2.21.1804241526320.238665@chino.kir.corp.google.com
Fixes: 2129258024 ("mm: oom: let oom_reap_task and exit_mmap run concurrently")
Signed-off-by: David Rientjes <rientjes@google.com>
Suggested-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org>	[4.14+]
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>
2018-05-16 10:10:27 +02:00
..
kasan License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Kconfig mm/hmm: avoid bloating arch that do not make use of HMM 2017-09-08 18:26:46 -07:00
Kconfig.debug kmemcheck: rip it out 2018-02-22 15:42:24 +01:00
Makefile kmemcheck: rip it out 2018-02-22 15:42:24 +01:00
backing-dev.c bdi: wake up concurrent wb_shutdown() callers. 2018-05-16 10:10:25 +02:00
balloon_compaction.c mm/migrate: new migrate mode MIGRATE_SYNC_NO_COPY 2017-09-08 18:26:46 -07:00
bootmem.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
cleancache.c fs: switch ->s_uuid to uuid_t 2017-06-05 16:59:12 +02:00
cma.c mm/cma.c: take __GFP_NOWARN into account in cma_alloc() 2017-10-13 16:18:32 -07:00
cma.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
cma_debug.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
compaction.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
debug.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
debug_page_ref.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
dmapool.c
early_ioremap.c mm/early_ioremap: Fix boot hang with earlyprintk=efi,keep 2018-02-25 11:08:03 +01:00
fadvise.c mm/fadvise: discard partial page if endbyte is also EOF 2018-04-26 11:02:15 +02:00
failslab.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
filemap.c mm/filemap.c: fix NULL pointer in page_cache_tree_insert() 2018-04-24 09:36:39 +02:00
frame_vector.c mm/frame_vector.c: release a semaphore in 'get_vaddr_frames()' 2018-03-03 10:24:21 +01:00
frontswap.c
gup.c get_user_pages_fast(): return -EFAULT on access_ok failure 2018-04-19 08:56:19 +02:00
highmem.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
hmm.c mm/hmm: hmm_pfns_bad() was accessing wrong struct 2018-04-24 09:36:22 +02:00
huge_memory.c mm/thp: do not wait for lock_page() in deferred_split_scan() 2018-03-28 18:24:39 +02:00
hugetlb.c hugetlbfs: check for pgoff value overflow 2018-03-28 18:24:38 +02:00
hugetlb_cgroup.c
hwpoison-inject.c mm: hwpoison: call shake_page() unconditionally 2017-05-03 15:52:12 -07:00
init-mm.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
internal.h mm, oom: do not rely on TIF_MEMDIE for memory reserves access 2017-09-06 17:27:30 -07:00
interval_tree.c lib/interval_tree: fast overlap detection 2017-09-08 18:26:49 -07:00
khugepaged.c mm: thp: use down_read_trylock() in khugepaged to avoid long block 2018-04-26 11:02:14 +02:00
kmemleak-test.c
kmemleak.c kmemcheck: remove annotations 2018-02-22 15:42:23 +01:00
ksm.c mm/ksm.c: fix inconsistent accounting of zero pages 2018-04-24 09:36:22 +02:00
list_lru.c mm: memcontrol: use vmalloc fallback for large kmem memcg arrays 2017-10-03 17:54:25 -07:00
maccess.c
madvise.c mm/madvise.c: fix madvise() infinite loop under special circumstances 2017-12-05 11:26:29 +01:00
memblock.c Revert "mm: page_alloc: skip over regions of invalid pfns where possible" 2018-03-28 18:24:39 +02:00
memcontrol.c memcg: fix per_node_info cleanup 2018-05-16 10:10:24 +02:00
memory-failure.c x86/mm, mm/hwpoison: Don't unconditionally unmap kernel 1:1 pages 2018-02-22 15:42:31 +01:00
memory.c mm: hide a #warning for COMPILE_TEST 2018-02-22 15:42:27 +01:00
memory_hotplug.c mm/memory_hotplug: define find_{smallest|biggest}_section_pfn as unsigned long 2017-10-03 17:54:26 -07:00
mempolicy.c mm/mempolicy: add nodes_empty check in SYSC_migrate_pages 2018-04-26 11:02:14 +02:00
mempool.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
memtest.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
migrate.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mincore.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mlock.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mm_init.c
mmap.c mm, oom: fix concurrent munlock and oom reaper unmap, v3 2018-05-16 10:10:27 +02:00
mmu_context.c
mmu_notifier.c mm/mmu_notifier: kill invalidate_page 2017-08-31 16:13:00 -07:00
mmzone.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mprotect.c mm/mprotect: add a cond_resched() inside change_pmd_range() 2018-01-10 09:31:17 +01:00
mremap.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
msync.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
nobootmem.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
nommu.c Merge branch 'work.set_fs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-09-14 18:13:32 -07:00
oom_kill.c mm, oom: fix concurrent munlock and oom reaper unmap, v3 2018-05-16 10:10:27 +02:00
page-writeback.c writeback: safer lock nesting 2018-04-24 09:36:39 +02:00
page_alloc.c Revert "mm: page_alloc: skip over regions of invalid pfns where possible" 2018-03-28 18:24:39 +02:00
page_counter.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
page_ext.c mm/page_ext.c: check if page_ext is not prepared 2017-11-24 08:37:05 +01:00
page_idle.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
page_io.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
page_isolation.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
page_owner.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
page_poison.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
page_vma_mapped.c mm, page_vma_mapped: Drop faulty pointer arithmetics in check_pte() 2018-01-23 19:58:21 +01:00
pagewalk.c mm/pagewalk.c: report holes in hugetlb ranges 2017-11-24 08:37:04 +01:00
percpu-internal.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
percpu-km.c percpu: add __GFP_NORETRY semantics to the percpu balancing path 2018-04-08 14:26:29 +02:00
percpu-stats.c percpu: fix starting offset for chunk statistics traversal 2017-09-27 14:45:57 -07:00
percpu-vm.c percpu: add __GFP_NORETRY semantics to the percpu balancing path 2018-04-08 14:26:29 +02:00
percpu.c percpu: include linux/sched.h for cond_resched() 2018-05-09 09:51:48 +02:00
pgtable-generic.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
process_vm_access.c
quicklist.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
readahead.c
rmap.c lib/interval_tree: fast overlap detection 2017-09-08 18:26:49 -07:00
rodata_test.c mm: fix RODATA_TEST failure "rodata_test: test data was not read only" 2017-10-03 17:54:24 -07:00
shmem.c mm/shmem: do not wait for lock_page() in shmem_unused_huge_shrink() 2018-03-28 18:24:39 +02:00
slab.c mm, slab: reschedule cache_reap() on the same CPU 2018-04-24 09:36:23 +02:00
slab.h kmemcheck: stop using GFP_NOTRACK and SLAB_NOTRACK 2018-02-22 15:42:23 +01:00
slab_common.c kmemcheck: stop using GFP_NOTRACK and SLAB_NOTRACK 2018-02-22 15:42:23 +01:00
slob.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
slub.c kmemcheck: rip it out 2018-02-22 15:42:24 +01:00
sparse-vmemmap.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
sparse.c mm: sections are not offlined during memory hotremove 2018-05-16 10:10:27 +02:00
swap.c mm: avoid marking swap cached page as lazyfree 2017-10-03 17:54:24 -07:00
swap_cgroup.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
swap_slots.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
swap_state.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
swapfile.c mm, swap: fix race between swap count continuation operations 2017-11-03 07:39:19 -07:00
truncate.c mm/truncate.c: fix THP handling in invalidate_mapping_pages() 2017-07-10 16:32:32 -07:00
usercopy.c mm/usercopy: Drop extra is_vmalloc_or_module() check 2017-04-05 12:30:18 -07:00
userfaultfd.c userfaultfd: shmem: wire up shmem_mfill_zeropage_pte 2017-09-06 17:27:28 -07:00
util.c mm: rename global_page_state to global_zone_page_state 2017-09-06 17:27:29 -07:00
vmacache.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
vmalloc.c vmalloc: fix __GFP_HIGHMEM usage for vmalloc_32 on 32b systems 2018-02-25 11:08:04 +01:00
vmpressure.c mm, vmpressure: pass-through notification support 2017-07-10 16:32:31 -07:00
vmscan.c mm: pin address_space before dereferencing it while isolating an LRU page 2018-04-26 11:02:15 +02:00
vmstat.c mm: consider the number in local CPUs when reading NUMA stats 2017-09-08 18:26:47 -07:00
workingset.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
z3fold.c z3fold: fix reclaim lock-ups 2018-05-16 10:10:27 +02:00
zbud.c
zpool.c
zsmalloc.c zsmalloc: calling zs_map_object() from irq is a bug 2017-12-14 09:53:10 +01:00
zswap.c mm, swap, frontswap: fix THP swap if frontswap enabled 2018-02-28 10:19:41 +01:00