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Andrea Arcangeli b4fecc67cc ksm: fix use after free with merge_across_nodes = 0
If merge_across_nodes was manually set to 0 (not the default value) by
the admin or a tuned profile on NUMA systems triggering cross-NODE page
migrations, a stable_node use after free could materialize.

If the chain is collapsed stable_node would point to the old chain that
was already freed.  stable_node_dup would be the stable_node dup now
converted to a regular stable_node and indexed in the rbtree in
replacement of the freed stable_node chain (not anymore a dup).

This special case where the chain is collapsed in the NUMA replacement
path, is now detected by setting stable_node to NULL by the chain_prune
callee if it decides to collapse the chain.  This tells the NUMA
replacement code that even if stable_node and stable_node_dup are
different, this is not a chain if stable_node is NULL, as the
stable_node_dup was converted to a regular stable_node and the chain was
collapsed.

It is generally safer for the callee to force the caller stable_node to
NULL the moment it become stale so any other mistake like this would
result in an instant Oops easier to debug than an use after free.

Otherwise the replace logic would act like if stable_node was a valid
chain, when in fact it was freed.  Notably
stable_node_chain_add_dup(page_node, stable_node) would run on a stable
stable_node.

Andrey Ryabinin found the source of the use after free in chain_prune().

Link: http://lkml.kernel.org/r/20170512193805.8807-2-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reported-by: Evgheni Dereveanchin <ederevea@redhat.com>
Tested-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Petr Holasek <pholasek@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Gavin Guo <gavin.guo@canonical.com>
Cc: Jay Vosburgh <jay.vosburgh@canonical.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>
2017-07-06 16:24:31 -07:00
..
kasan Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-05-10 10:30:46 -07:00
Kconfig Merge branch 'for-4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu 2017-07-06 08:59:41 -07:00
Kconfig.debug mm: enable page poisoning early at boot 2017-05-03 15:52:10 -07:00
Makefile percpu: expose statistics about percpu memory via debugfs 2017-06-20 15:31:38 -04:00
backing-dev.c bdi: Drop 'parent' argument from bdi_register[_va]() 2017-04-20 12:09:55 -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/bootmem.c: cosmetic improvement of code readability 2017-02-22 16:41:29 -08:00
cleancache.c fs: switch ->s_uuid to uuid_t 2017-06-05 16:59:12 +02:00
cma.c cma: Introduce cma_for_each_area 2017-04-18 20:41:12 +02:00
cma.h cma: Store a name in the cma structure 2017-04-18 20:41:12 +02:00
cma_debug.c cma: Store a name in the cma structure 2017-04-18 20:41:12 +02:00
compaction.c mm, compaction: finish whole pageblock to reduce fragmentation 2017-05-08 17:15:10 -07:00
debug.c mm, debug: print raw struct page data in __dump_page() 2016-12-12 18:55:08 -08:00
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 lib/vsprintf.c: remove %Z support 2017-02-27 18:43:47 -08:00
early_ioremap.c mm/early_ioremap: use offset_in_page macro 2015-11-05 19:34:48 -08:00
fadvise.c mm: fadvise: avoid expensive remote LRU cache draining after FADV_DONTNEED 2016-12-20 09:48:46 -08:00
failslab.c mm: fault-inject take over bootstrap kmem_cache check 2016-03-15 16:55:16 -07:00
filemap.c Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-07-03 13:08:04 -07:00
frame_vector.c treewide: use kv[mz]alloc* rather than opencoded variants 2017-05-08 17:15:13 -07:00
frontswap.c mm, frontswap: convert frontswap_enabled to static key 2016-07-26 16:19:19 -07:00
gup.c Merge branch 'linus' into x86/mm, to pick up fixes 2017-06-22 10:57:28 +02:00
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 thp, mm: fix crash due race in MADV_FREE handling 2017-07-06 16:24:29 -07:00
hugetlb.c mm/hugetlb: report -EHWPOISON not -EFAULT when FOLL_HWPOISON is specified 2017-06-02 15:07:38 -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 mm: hwpoison: call shake_page() unconditionally 2017-05-03 15:52:12 -07:00
init-mm.c mm: Add a user_ns owner to mm_struct and fix ptrace permission checks 2016-11-22 11:49:48 -06:00
internal.h mm, compaction: finish whole pageblock to reduce fragmentation 2017-05-08 17:15:10 -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: remove cond_resched from __collapse_huge_page_copy 2017-06-23 16:15:55 -07:00
kmemcheck.c mm: Rename SLAB_DESTROY_BY_RCU to SLAB_TYPESAFE_BY_RCU 2017-04-18 11:42:36 -07:00
kmemleak-test.c mm: convert printk(KERN_<LEVEL> to pr_<level> 2016-03-17 15:09:34 -07:00
kmemleak.c mm: fix section name for .data..ro_after_init 2017-03-31 17:13:30 -07:00
ksm.c ksm: fix use after free with merge_across_nodes = 0 2017-07-06 16:24:31 -07:00
list_lru.c mm/list_lru.c: avoid error-path NULL pointer deref 2016-10-27 18:43:42 -07:00
maccess.c x86: remove more uaccess_32.h complexity 2016-05-22 17:21:27 -07:00
madvise.c mm/madvise: move up the behavior parameter validation 2017-05-03 15:52:11 -07:00
memblock.c mm: consider memblock reservations for deferred memory initialization sizing 2017-06-02 15:07:38 -07:00
memcontrol.c sched/wait: Disambiguate wq_entry->task_list and wq_head->task_list naming 2017-06-20 12:19:14 +02:00
memory-failure.c mm/memory-failure.c: use compound_head() flags for huge pages 2017-06-17 06:37:05 +09:00
memory.c mm: larger stack guard gap, between vmas 2017-06-19 21:50:20 +08:00
memory_hotplug.c mm, vmscan: prevent kswapd sleeping prematurely due to mismatched classzone_idx 2017-05-03 15:52:09 -07:00
mempolicy.c mm/mempolicy.c: fix error handling in set_mempolicy and mbind. 2017-04-08 10:57:55 -07:00
mempool.c sched/wait: Rename wait_queue_t => wait_queue_entry_t 2017-06-20 12:18:27 +02:00
memtest.c memtest: remove unused header files 2015-09-08 15:35:28 -07:00
migrate.c mm: make rmap_one boolean function 2017-05-03 15:52:10 -07:00
mincore.c mm: remove shmem_mapping() shmem_zero_setup() duplicates 2017-02-24 17:46:56 -08:00
mlock.c mlock: fix mlock count can not decrease in race condition 2017-06-02 15:07:38 -07:00
mm_init.c mm: convert printk(KERN_<LEVEL> to pr_<level> 2016-03-17 15:09:34 -07:00
mmap.c mm/mmap.c: mark protection_map as __ro_after_init 2017-07-06 16:24:31 -07:00
mmu_context.c sched/headers: Prepare to move the task_lock()/unlock() APIs to <linux/sched/task.h> 2017-03-02 08:42:38 +01:00
mmu_notifier.c mm: Use static initialization for "srcu" 2017-04-18 11:38:22 -07:00
mmzone.c mm/mmzone.c: swap likely to unlikely as code logic is different for next_zones_zonelist() 2017-02-22 16:41:29 -08:00
mprotect.c mm: convert generic code to 5-level paging 2017-03-09 11:48:47 -08:00
mremap.c mm: convert generic code to 5-level paging 2017-03-09 11:48:47 -08:00
msync.c mm/msync: use offset_in_page macro 2015-11-05 19:34:48 -08:00
nobootmem.c mm/nobootmem.c: return 0 when start_pfn equals end_pfn 2017-07-06 16:24:31 -07:00
nommu.c mm, vmalloc: use __GFP_HIGHMEM implicitly 2017-05-08 17:15:13 -07:00
oom_kill.c oom: improve oom disable handling 2017-05-03 15:52:10 -07:00
page-writeback.c Add GETFSMAP support; some performance improvements for very large 2017-05-08 11:30:05 -07:00
page_alloc.c mm: consider memblock reservations for deferred memory initialization sizing 2017-06-02 15:07:38 -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: enable page poisoning early at boot 2017-05-03 15:52:10 -07:00
page_idle.c mm: make rmap_one boolean function 2017-05-03 15:52:10 -07:00
page_io.c block: switch bios to blk_status_t 2017-06-09 09:27:32 -06:00
page_isolation.c mm, page_alloc: count movable pages when stealing from pageblock 2017-05-08 17:15:10 -07:00
page_owner.c mm/page_owner: don't define fields on struct page_ext by hard-coding 2016-10-07 18:46:27 -07:00
page_poison.c mm: enable page poisoning early at boot 2017-05-03 15:52:10 -07:00
page_vma_mapped.c mm: fix page_vma_mapped_walk() for ksm pages 2017-04-08 00:47:48 -07:00
pagewalk.c mm: convert generic code to 5-level paging 2017-03-09 11:48:47 -08:00
percpu-internal.h percpu: fix early calls for spinlock in pcpu_stats 2017-06-21 13:53:52 -04:00
percpu-km.c percpu: fix static checker warnings in pcpu_destroy_chunk 2017-06-29 11:23:38 -04:00
percpu-stats.c percpu: expose statistics about percpu memory via debugfs 2017-06-20 15:31:38 -04:00
percpu-vm.c percpu: fix static checker warnings in pcpu_destroy_chunk 2017-06-29 11:23:38 -04:00
percpu.c percpu: resolve err may not be initialized in pcpu_alloc 2017-06-21 12:00:45 -04:00
pgtable-generic.c mm: convert generic code to 5-level paging 2017-03-09 11:48:47 -08:00
process_vm_access.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/mm.h> 2017-03-02 08:42:28 +01:00
quicklist.c fix Christoph's email addresses 2016-03-17 15:09:34 -07:00
readahead.c mm: don't cap request size based on read-ahead setting 2016-12-12 18:55:08 -08:00
rmap.c mm, x86/mm: Make the batched unmap TLB flush API more generic 2017-05-24 10:18:27 +02:00
rodata_test.c mm: remove rodata_test_data export, add pr_fmt 2017-05-03 15:52:09 -07:00
shmem.c Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-07-03 13:08:04 -07:00
slab.c mm/slab.c: replace open-coded round-up code with ALIGN 2017-07-06 16:24:30 -07:00
slab.h mm: Rename SLAB_DESTROY_BY_RCU to SLAB_TYPESAFE_BY_RCU 2017-04-18 11:42:36 -07:00
slab_common.c mm: allow slab_nomerge to be set at build time 2017-07-06 16:24:31 -07:00
slob.c mm: Rename SLAB_DESTROY_BY_RCU to SLAB_TYPESAFE_BY_RCU 2017-04-18 11:42:36 -07:00
slub.c mm/slub.c: wrap kmem_cache->cpu_partial in config CONFIG_SLUB_CPU_PARTIAL 2017-07-06 16:24:30 -07:00
sparse-vmemmap.c mm: convert generic code to 5-level paging 2017-03-09 11:48:47 -08:00
sparse.c mm, sparsemem: break out of loops early 2017-07-06 16:24:31 -07:00
swap.c mm: move MADV_FREE pages into LRU_INACTIVE_FILE list 2017-05-03 15:52:08 -07:00
swap_cgroup.c swap: cond_resched in swap_cgroup_prepare() 2017-06-17 06:37:05 +09:00
swap_slots.c mm, swap: use kvzalloc to allocate some swap data structures 2017-05-08 17:15:13 -07:00
swap_state.c mm, swap: use kvzalloc to allocate some swap data structures 2017-05-08 17:15:13 -07:00
swapfile.c mm, swap: use kvzalloc to allocate some swap data structures 2017-05-08 17:15:13 -07:00
truncate.c mm: fix data corruption due to stale mmap reads 2017-05-12 15:57:15 -07:00
usercopy.c mm/usercopy: Drop extra is_vmalloc_or_module() check 2017-04-05 12:30:18 -07:00
userfaultfd.c mm: convert generic code to 5-level paging 2017-03-09 11:48:47 -08:00
util.c mm: clarify why we want kmalloc before falling backto vmallock 2017-06-02 15:07:37 -07:00
vmacache.c sched/headers: Prepare to move 'init_task' and 'init_thread_union' from <linux/sched.h> to <linux/sched/task.h> 2017-03-02 08:42:38 +01:00
vmalloc.c mm/vmalloc.c: huge-vmap: fail gracefully on unexpected huge vmap mappings 2017-06-23 16:15:55 -07:00
vmpressure.c mm: correct the comment when reclaimed pages exceed the scanned pages 2017-06-17 06:37:05 +09:00
vmscan.c mm/vmscan.c: fix unsequenced modification and access warning 2017-07-06 16:24:31 -07:00
vmstat.c mm, vmstat: Remove spurious WARN() during zoneinfo print 2017-05-12 15:57:15 -07:00
workingset.c mm: memcontrol: use node page state naming scheme for memcg 2017-05-03 15:52:11 -07:00
z3fold.c z3fold: fix page locking in z3fold_alloc() 2017-04-13 18:24:20 -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: expand class bit 2017-04-13 18:24:21 -07:00
zswap.c zswap: don't param_set_charp while holding spinlock 2017-02-27 18:43:45 -08:00