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Pavel Tatashin 3010f87650 mm: discard memblock data later 
There is existing use after free bug when deferred struct pages are
enabled:

The memblock_add() allocates memory for the memory array if more than
128 entries are needed.  See comment in e820__memblock_setup():

  * The bootstrap memblock region count maximum is 128 entries
  * (INIT_MEMBLOCK_REGIONS), but EFI might pass us more E820 entries
  * than that - so allow memblock resizing.

This memblock memory is freed here:
        free_low_memory_core_early()

We access the freed memblock.memory later in boot when deferred pages
are initialized in this path:

        deferred_init_memmap()
                for_each_mem_pfn_range()
                  __next_mem_pfn_range()
                    type = &memblock.memory;

One possible explanation for why this use-after-free hasn't been hit
before is that the limit of INIT_MEMBLOCK_REGIONS has never been
exceeded at least on systems where deferred struct pages were enabled.

Tested by reducing INIT_MEMBLOCK_REGIONS down to 4 from the current 128,
and verifying in qemu that this code is getting excuted and that the
freed pages are sane.

Link: http://lkml.kernel.org/r/1502485554-318703-2-git-send-email-pasha.tatashin@oracle.com
Fixes: 7e18adb4f8 ("mm: meminit: initialise remaining struct pages in parallel with kswapd")
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: Steven Sistare <steven.sistare@oracle.com>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Reviewed-by: Bob Picco <bob.picco@oracle.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 		2017-08-18 15:32:01 -07:00
..
kasan kasan: avoid -Wmaybe-uninitialized warning 2017-08-02 16:34:46 -07:00
Kconfig mm/kasan: add support for memory hotplug 2017-07-10 16:32:33 -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
…
balloon_compaction.c mm/balloon_compaction.c: don't zero ballooned pages 2017-08-10 15:54:07 -07:00
bootmem.c
…
cleancache.c fs: switch ->s_uuid to uuid_t 2017-06-05 16:59:12 +02:00
cma.c cma: fix calculation of aligned offset 2017-07-10 16:32:32 -07:00
cma.h
…
cma_debug.c
…
compaction.c mm, compaction: skip over holes in __reset_isolation_suitable 2017-07-06 16:24:32 -07:00
debug.c mm: make tlb_flush_pending global 2017-08-10 15:54:07 -07:00
debug_page_ref.c
…
dmapool.c
…
early_ioremap.c
…
fadvise.c
…
failslab.c
…
filemap.c mm: hugetlb: return immediately for hugetlb page in __delete_from_page_cache() 2017-07-10 16:32:30 -07:00
frame_vector.c treewide: use kv[mz]alloc* rather than opencoded variants 2017-05-08 17:15:13 -07:00
frontswap.c
…
gup.c mm, gup: ensure real head page is ref-counted when using hugepages 2017-07-06 16:24:34 -07:00
highmem.c
…
huge_memory.c Revert "mm: numa: defer TLB flush for THP migration as long as possible" 2017-08-10 15:54:07 -07:00
hugetlb.c userfaultfd: hugetlbfs: remove superfluous page unlock in VM_SHARED case 2017-08-10 15:54:06 -07:00
hugetlb_cgroup.c
…
hwpoison-inject.c mm: hwpoison: call shake_page() unconditionally 2017-05-03 15:52:12 -07:00
init-mm.c
…
internal.h mm, mprotect: flush TLB if potentially racing with a parallel reclaim leaving stale TLB entries 2017-08-02 16:34:46 -07:00
interval_tree.c
…
khugepaged.c mm: make PR_SET_THP_DISABLE immediately active 2017-07-10 16:32:31 -07:00
kmemcheck.c
…
kmemleak-test.c
…
kmemleak.c mm: kmemleak: treat vm_struct as alternative reference to vmalloc'ed objects 2017-07-06 16:24:34 -07:00
ksm.c mm: fix KSM data corruption 2017-08-10 15:54:07 -07:00
list_lru.c mm/list_lru.c: fix list_lru_count_node() to be race free 2017-07-10 16:32:33 -07:00
maccess.c
…
madvise.c mm, mprotect: flush TLB if potentially racing with a parallel reclaim leaving stale TLB entries 2017-08-02 16:34:46 -07:00
memblock.c mm: discard memblock data later 2017-08-18 15:32:01 -07:00
memcontrol.c mm: memcontrol: fix NULL pointer crash in test_clear_page_writeback() 2017-08-18 15:32:01 -07:00
memory-failure.c mm, hugetlb, soft_offline: use new_page_nodemask for soft offline migration 2017-07-10 16:32:32 -07:00
memory.c mm: fix MADV_[FREE|DONTNEED] TLB flush miss problem 2017-08-10 15:54:07 -07:00
memory_hotplug.c mm/memory-hotplug: switch locking to a percpu rwsem 2017-07-10 16:32:33 -07:00
mempolicy.c mm, migration: do not trigger OOM killer when migrating memory 2017-07-12 16:26:04 -07:00
mempool.c sched/wait: Rename wait_queue_t => wait_queue_entry_t 2017-06-20 12:18:27 +02:00
memtest.c
…
migrate.c Revert "mm: numa: defer TLB flush for THP migration as long as possible" 2017-08-10 15:54:07 -07:00
mincore.c
…
mlock.c mlock: fix mlock count can not decrease in race condition 2017-06-02 15:07:38 -07:00
mm_init.c
…
mmap.c mm: fix overflow check in expand_upwards() 2017-07-14 15:05:12 -07:00
mmu_context.c
…
mmu_notifier.c
…
mmzone.c
…
mprotect.c mm: migrate: prevent racy access to tlb_flush_pending 2017-08-10 15:54:07 -07:00
mremap.c userfaultfd: non-cooperative: notify about unmap of destination during mremap 2017-08-02 16:34:46 -07:00
msync.c
…
nobootmem.c mm: discard memblock data later 2017-08-18 15:32:01 -07:00
nommu.c mm, vmalloc: use __GFP_HIGHMEM implicitly 2017-05-08 17:15:13 -07:00
oom_kill.c mm/oom_kill.c: add tracepoints for oom reaper-related events 2017-07-10 16:32:32 -07:00
page-writeback.c mm: memcontrol: fix NULL pointer crash in test_clear_page_writeback() 2017-08-18 15:32:01 -07:00
page_alloc.c mm: discard memblock data later 2017-08-18 15:32:01 -07:00
page_counter.c
…
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 mm/page_io.c: fix oops during block io poll in swapin path 2017-08-02 17:16:11 -07:00
page_isolation.c mm: unify new_node_page and alloc_migrate_target 2017-07-10 16:32:31 -07:00
page_owner.c mm: avoid taking zone lock in pagetypeinfo_showmixed() 2017-07-10 16:32:32 -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/hugetlb: add size parameter to huge_pte_offset() 2017-07-06 16:24:34 -07:00
pagewalk.c mm/hugetlb: add size parameter to huge_pte_offset() 2017-07-06 16:24:34 -07:00
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
…
process_vm_access.c
…
quicklist.c
…
readahead.c
…
rmap.c rmap: do not call mmu_notifier_invalidate_page() under ptl 2017-08-10 15:54:07 -07:00
rodata_test.c mm: remove rodata_test_data export, add pr_fmt 2017-05-03 15:52:09 -07:00
shmem.c mm: fix list corruptions on shmem shrinklist 2017-08-10 15:54:07 -07:00
slab.c mm: memcontrol: account slab stats per lruvec 2017-07-06 16:24:35 -07:00
slab.h mm: memcontrol: account slab stats per lruvec 2017-07-06 16:24:35 -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
…
slub.c mm: memcontrol: account slab stats per lruvec 2017-07-06 16:24:35 -07:00
sparse-vmemmap.c mm, tree wide: replace __GFP_REPEAT by __GFP_RETRY_MAYFAIL with more useful semantic 2017-07-12 16:26:03 -07:00
sparse.c mm, memory_hotplug: do not associate hotadded memory to zones until online 2017-07-06 16:24:32 -07:00
swap.c mm: swap: provide lru_add_drain_all_cpuslocked() 2017-07-10 16:32:33 -07:00
swap_cgroup.c mm, THP, swap: delay splitting THP during swap out 2017-07-06 16:24:31 -07:00
swap_slots.c mm/swap_slots.c: don't disable preemption while taking the per-CPU cache 2017-07-10 16:32:32 -07:00
swap_state.c swap: add block io poll in swapin path 2017-07-10 16:32:30 -07:00
swapfile.c swap: add block io poll in swapin path 2017-07-10 16:32:30 -07:00
truncate.c mm/truncate.c: fix THP handling in invalidate_mapping_pages() 2017-07-10 16:32:32 -07:00
usercopy.c
…
userfaultfd.c
…
util.c mm: fix global NR_SLAB_.*CLAIMABLE counter reads 2017-08-10 15:54:06 -07:00
vmacache.c
…
vmalloc.c mm, tree wide: replace __GFP_REPEAT by __GFP_RETRY_MAYFAIL with more useful semantic 2017-07-12 16:26:03 -07:00
vmpressure.c mm, vmpressure: pass-through notification support 2017-07-10 16:32:31 -07:00
vmscan.c mm, tree wide: replace __GFP_REPEAT by __GFP_RETRY_MAYFAIL with more useful semantic 2017-07-12 16:26:03 -07:00
vmstat.c mm: avoid taking zone lock in pagetypeinfo_showmixed() 2017-07-10 16:32:32 -07:00
workingset.c mm: memcontrol: per-lruvec stats infrastructure 2017-07-06 16:24:35 -07:00
z3fold.c
…
zbud.c
…
zpool.c
…
zsmalloc.c zram: do not free pool->size_class 2017-08-02 16:34:47 -07:00
zswap.c mm/zswap.c: delete an error message for a failed memory allocation in zswap_dstmem_prepare() 2017-07-06 16:24:35 -07:00