linux/mm
Daniel Vacek 864b75f9d6 mm/page_alloc: fix memmap_init_zone pageblock alignment
Commit b92df1de5d ("mm: page_alloc: skip over regions of invalid pfns
where possible") introduced a bug where move_freepages() triggers a
VM_BUG_ON() on uninitialized page structure due to pageblock alignment.
To fix this, simply align the skipped pfns in memmap_init_zone() the
same way as in move_freepages_block().

Seen in one of the RHEL reports:

  crash> log | grep -e BUG -e RIP -e Call.Trace -e move_freepages_block -e rmqueue -e freelist -A1
  kernel BUG at mm/page_alloc.c:1389!
  invalid opcode: 0000 [#1] SMP
  --
  RIP: 0010:[<ffffffff8118833e>]  [<ffffffff8118833e>] move_freepages+0x15e/0x160
  RSP: 0018:ffff88054d727688  EFLAGS: 00010087
  --
  Call Trace:
   [<ffffffff811883b3>] move_freepages_block+0x73/0x80
   [<ffffffff81189e63>] __rmqueue+0x263/0x460
   [<ffffffff8118c781>] get_page_from_freelist+0x7e1/0x9e0
   [<ffffffff8118caf6>] __alloc_pages_nodemask+0x176/0x420
  --
  RIP  [<ffffffff8118833e>] move_freepages+0x15e/0x160
   RSP <ffff88054d727688>

  crash> page_init_bug -v | grep RAM
  <struct resource 0xffff88067fffd2f8>          1000 -        9bfff	System RAM (620.00 KiB)
  <struct resource 0xffff88067fffd3a0>        100000 -     430bffff	System RAM (  1.05 GiB = 1071.75 MiB = 1097472.00 KiB)
  <struct resource 0xffff88067fffd410>      4b0c8000 -     4bf9cfff	System RAM ( 14.83 MiB = 15188.00 KiB)
  <struct resource 0xffff88067fffd480>      4bfac000 -     646b1fff	System RAM (391.02 MiB = 400408.00 KiB)
  <struct resource 0xffff88067fffd560>      7b788000 -     7b7fffff	System RAM (480.00 KiB)
  <struct resource 0xffff88067fffd640>     100000000 -    67fffffff	System RAM ( 22.00 GiB)

  crash> page_init_bug | head -6
  <struct resource 0xffff88067fffd560>      7b788000 -     7b7fffff	System RAM (480.00 KiB)
  <struct page 0xffffea0001ede200>   1fffff00000000  0 <struct pglist_data 0xffff88047ffd9000> 1 <struct zone 0xffff88047ffd9800> DMA32          4096    1048575
  <struct page 0xffffea0001ede200> 505736 505344 <struct page 0xffffea0001ed8000> 505855 <struct page 0xffffea0001edffc0>
  <struct page 0xffffea0001ed8000>                0  0 <struct pglist_data 0xffff88047ffd9000> 0 <struct zone 0xffff88047ffd9000> DMA               1       4095
  <struct page 0xffffea0001edffc0>   1fffff00000400  0 <struct pglist_data 0xffff88047ffd9000> 1 <struct zone 0xffff88047ffd9800> DMA32          4096    1048575
  BUG, zones differ!

Note that this range follows two not populated sections
68000000-77ffffff in this zone.  7b788000-7b7fffff is the first one
after a gap.  This makes memmap_init_zone() skip all the pfns up to the
beginning of this range.  But this range is not pageblock (2M) aligned.
In fact no range has to be.

  crash> kmem -p 77fff000 78000000 7b5ff000 7b600000 7b787000 7b788000
        PAGE        PHYSICAL      MAPPING       INDEX CNT FLAGS
  ffffea0001e00000  78000000                0        0  0 0
  ffffea0001ed7fc0  7b5ff000                0        0  0 0
  ffffea0001ed8000  7b600000                0        0  0 0	<<<<
  ffffea0001ede1c0  7b787000                0        0  0 0
  ffffea0001ede200  7b788000                0        0  1 1fffff00000000

Top part of page flags should contain nodeid and zonenr, which is not
the case for page ffffea0001ed8000 here (<<<<).

  crash> log | grep -o fffea0001ed[^\ ]* | sort -u
  fffea0001ed8000
  fffea0001eded20
  fffea0001edffc0

  crash> bt -r | grep -o fffea0001ed[^\ ]* | sort -u
  fffea0001ed8000
  fffea0001eded00
  fffea0001eded20
  fffea0001edffc0

Initialization of the whole beginning of the section is skipped up to
the start of the range due to the commit b92df1de5d.  Now any code
calling move_freepages_block() (like reusing the page from a freelist as
in this example) with a page from the beginning of the range will get
the page rounded down to start_page ffffea0001ed8000 and passed to
move_freepages() which crashes on assertion getting wrong zonenr.

  >         VM_BUG_ON(page_zone(start_page) != page_zone(end_page));

Note, page_zone() derives the zone from page flags here.

From similar machine before commit b92df1de5d28:

  crash> kmem -p 77fff000 78000000 7b5ff000 7b600000 7b7fe000 7b7ff000
        PAGE        PHYSICAL      MAPPING       INDEX CNT FLAGS
  fffff73941e00000  78000000                0        0  1 1fffff00000000
  fffff73941ed7fc0  7b5ff000                0        0  1 1fffff00000000
  fffff73941ed8000  7b600000                0        0  1 1fffff00000000
  fffff73941edff80  7b7fe000                0        0  1 1fffff00000000
  fffff73941edffc0  7b7ff000 ffff8e67e04d3ae0     ad84  1 1fffff00020068 uptodate,lru,active,mappedtodisk

All the pages since the beginning of the section are initialized.
move_freepages()' not gonna blow up.

The same machine with this fix applied:

  crash> kmem -p 77fff000 78000000 7b5ff000 7b600000 7b7fe000 7b7ff000
        PAGE        PHYSICAL      MAPPING       INDEX CNT FLAGS
  ffffea0001e00000  78000000                0        0  0 0
  ffffea0001e00000  7b5ff000                0        0  0 0
  ffffea0001ed8000  7b600000                0        0  1 1fffff00000000
  ffffea0001edff80  7b7fe000                0        0  1 1fffff00000000
  ffffea0001edffc0  7b7ff000 ffff88017fb13720        8  2 1fffff00020068 uptodate,lru,active,mappedtodisk

At least the bare minimum of pages is initialized preventing the crash
as well.

Customers started to report this as soon as 7.4 (where b92df1de5d was
merged in RHEL) was released.  I remember reports from
September/October-ish times.  It's not easily reproduced and happens on
a handful of machines only.  I guess that's why.  But that does not make
it less serious, I think.

Though there actually is a report here:
  https://bugzilla.kernel.org/show_bug.cgi?id=196443

And there are reports for Fedora from July:
  https://bugzilla.redhat.com/show_bug.cgi?id=1473242
and CentOS:
  https://bugs.centos.org/view.php?id=13964
and we internally track several dozens reports for RHEL bug
  https://bugzilla.redhat.com/show_bug.cgi?id=1525121

Link: http://lkml.kernel.org/r/0485727b2e82da7efbce5f6ba42524b429d0391a.1520011945.git.neelx@redhat.com
Fixes: b92df1de5d ("mm: page_alloc: skip over regions of invalid pfns where possible")
Signed-off-by: Daniel Vacek <neelx@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-03-09 16:40:01 -08:00
..
kasan kasan: fix prototype author email address 2018-02-06 18:32:43 -08:00
Kconfig mm: relax deferred struct page requirements 2018-01-31 17:18:36 -08:00
Kconfig.debug kmemcheck: rip it out 2017-11-15 18:21:05 -08:00
Makefile mm: add infrastructure for get_user_pages_fast() benchmarking 2017-11-17 16:10:04 -08:00
backing-dev.c Revert "bdi: add error handle for bdi_debug_register" 2017-12-21 10:01:30 -07:00
balloon_compaction.c virtio_balloon: fix deadlock on OOM 2017-11-14 23:57:38 +02:00
bootmem.c mm: docs: fix parameter names mismatch 2018-02-06 18:32:48 -08:00
cleancache.c fs: switch ->s_uuid to uuid_t 2017-06-05 16:59:12 +02:00
cma.c mm/cma.c: change pr_info to pr_err for cma_alloc fail log 2017-11-15 18:21:03 -08:00
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 mm/compaction.c: fix comment for try_to_compact_pages() 2018-01-31 17:18:39 -08:00
debug.c mm/debug.c: provide useful debugging information for VM_BUG 2018-01-04 16:45:09 -08:00
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 lib/vsprintf.c: remove %Z support 2017-02-27 18:43:47 -08:00
early_ioremap.c mm/early_ioremap: Fix boot hang with earlyprintk=efi,keep 2017-12-11 14:54:44 +01:00
fadvise.c mm/fadvise: discard partial page if endbyte is also EOF 2018-01-31 17:18:39 -08:00
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: remove include of hardirq.h 2018-01-31 17:18:36 -08:00
frame_vector.c mm/frame_vector.c: release a semaphore in 'get_vaddr_frames()' 2017-12-14 16:00:48 -08:00
frontswap.c mm, frontswap: convert frontswap_enabled to static key 2016-07-26 16:19:19 -07:00
gup.c mm/gup.c: teach get_user_pages_unlocked to handle FOLL_NOWAIT 2018-03-09 16:40:01 -08:00
gup_benchmark.c mm: add infrastructure for get_user_pages_fast() benchmarking 2017-11-17 16:10:04 -08:00
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 libnvdimm for 4.16 2018-02-06 10:41:33 -08:00
huge_memory.c mm/thp: remove pmd_huge_split_prepare() 2018-01-31 17:18:38 -08:00
hugetlb.c hugetlb: fix surplus pages accounting 2018-03-09 16:40:01 -08:00
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/memory_failure: Remove unused trapno from memory_failure 2018-01-23 12:17:42 -06:00
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 Revert "mm, thp: Do not make pmd/pud dirty without a reason" 2017-11-29 09:01:01 -08:00
interval_tree.c mm/interval_tree.c: use vma_pages() helper 2018-01-31 17:18:37 -08:00
khugepaged.c mm: thp: use down_read_trylock() in khugepaged to avoid long block 2018-01-31 17:18:38 -08:00
kmemleak-test.c mm: convert printk(KERN_<LEVEL> to pr_<level> 2016-03-17 15:09:34 -07:00
kmemleak.c mm: kmemleak: remove unused hardirq.h 2018-01-31 17:18:36 -08:00
ksm.c mm: docs: fixup punctuation 2018-02-06 18:32:48 -08:00
list_lru.c mm/list_lru.c: mark expected switch fall-through 2017-11-15 18:21:07 -08:00
maccess.c mm: docs: fix parameter names mismatch 2018-02-06 18:32:48 -08:00
madvise.c mm/memory_failure: Remove unused trapno from memory_failure 2018-01-23 12:17:42 -06:00
memblock.c mm/memblock.c: hardcode the end_pfn being -1 2018-03-09 16:40:01 -08:00
memcontrol.c vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
memory-failure.c x86/mm, mm/hwpoison: Don't unconditionally unmap kernel 1:1 pages 2018-02-13 16:25:06 +01:00
memory.c mm: hide a #warning for COMPILE_TEST 2018-02-16 09:41:36 -08:00
memory_hotplug.c libnvdimm for 4.16 2018-02-06 10:41:33 -08:00
mempolicy.c hugetlb, mbind: fall back to default policy if vma is NULL 2018-01-31 17:18:40 -08:00
mempool.c kasan: detect invalid frees for large mempool objects 2018-02-06 18:32:43 -08:00
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 mm, hugetlb: do not rely on overcommit limit during migration 2018-01-31 17:18:40 -08:00
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 mm, mlock, vmscan: no more skipping pagevecs 2018-02-21 15:35:42 -08:00
mm_init.c mm: convert printk(KERN_<LEVEL> to pr_<level> 2016-03-17 15:09:34 -07:00
mmap.c mm, oom_reaper: fix memory corruption 2017-12-14 16:00:49 -08:00
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, mmu_notifier: annotate mmu notifiers with blockable invalidate callbacks 2018-01-31 17:18:38 -08:00
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: numa: do not trap faults on shared data section pages. 2018-01-31 17:18:40 -08:00
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 mm: docs: fixup punctuation 2018-02-06 18:32:48 -08:00
oom_kill.c mm, oom: avoid reaping only for mm's with blockable invalidate callbacks 2018-01-31 17:18:38 -08:00
page-writeback.c Revert "mm/page-writeback.c: print a warning if the vm dirtiness settings are illogical" 2017-11-29 18:40:43 -08:00
page_alloc.c mm/page_alloc: fix memmap_init_zone pageblock alignment 2018-03-09 16:40:01 -08:00
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: make page_ext_init a noop when CONFIG_PAGE_EXTENSION but nothing uses it 2018-01-31 17:18:39 -08:00
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 block: convert to bio_first_bvec_all & bio_first_page_all 2018-01-06 09:18:00 -07:00
page_isolation.c mm: distinguish CMA and MOVABLE isolation in has_unmovable_pages() 2017-11-15 18:21:02 -08:00
page_owner.c mm/page_owner.c: clean up init_pages_in_zone() 2018-01-31 17:18:39 -08:00
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: Introduce pfn_in_hpage() 2018-01-22 12:15:57 -08:00
pagewalk.c mm: docs: add blank lines to silence sphinx "Unexpected indentation" errors 2018-02-06 18:32:48 -08:00
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: replace area map allocator with bitmap 2017-07-26 17:41:05 -04:00
percpu-stats.c percpu: fix starting offset for chunk statistics traversal 2017-09-27 14:45:57 -07:00
percpu-vm.c mm: remove __GFP_COLD 2017-11-15 18:21:06 -08:00
percpu.c percpu: hack to let the CRIS architecture to boot until they clean up 2017-11-27 12:53:12 -08:00
pgtable-generic.c mm: do not lose dirty and accessed bits in pmdp_invalidate() 2018-01-31 17:18:38 -08:00
process_vm_access.c mm: docs: add blank lines to silence sphinx "Unexpected indentation" errors 2018-02-06 18:32:48 -08:00
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 mm: don't cap request size based on read-ahead setting 2016-12-12 18:55:08 -08:00
rmap.c mm: remove cold parameter from free_hot_cold_page* 2017-11-15 18:21:06 -08:00
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 shmem: add sealing support to hugetlb-backed memfd 2018-01-31 17:18:39 -08:00
slab.c kasan: don't use __builtin_return_address(1) 2018-02-06 18:32:43 -08:00
slab.h Currently, hardened usercopy performs dynamic bounds checking on slab 2018-02-03 16:25:42 -08:00
slab_common.c Currently, hardened usercopy performs dynamic bounds checking on slab 2018-02-03 16:25:42 -08:00
slob.c slab, slub, slob: add slab_flags_t 2017-11-15 18:21:01 -08:00
slub.c kasan: don't use __builtin_return_address(1) 2018-02-06 18:32:43 -08:00
sparse-vmemmap.c mm: merge vmem_altmap_alloc into altmap_alloc_block_buf 2018-01-08 11:46:23 -08:00
sparse.c libnvdimm for 4.16 2018-02-06 10:41:33 -08:00
swap.c mm/swap.c: make functions and their kernel-doc agree (again) 2018-02-21 15:35:43 -08:00
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 mm/swap_slots.c: fix race conditions in swap_slots cache init 2017-11-15 18:21:03 -08:00
swap_state.c mm: remove cold parameter for release_pages 2017-11-15 18:21:06 -08:00
swapfile.c vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
truncate.c mm: add unmap_mapping_pages() 2018-01-31 17:18:37 -08:00
usercopy.c usercopy: WARN() on slab cache usercopy region violations 2018-01-15 12:07:48 -08:00
userfaultfd.c mm/userfaultfd.c: remove duplicate include 2018-02-06 18:32:47 -08:00
util.c new primitive: vmemdup_user() 2018-01-07 13:06:15 -05:00
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 2018-02-21 15:35:43 -08:00
vmpressure.c mm, vmpressure: pass-through notification support 2017-07-10 16:32:31 -07:00
vmscan.c mm, mlock, vmscan: no more skipping pagevecs 2018-02-21 15:35:42 -08:00
vmstat.c mm, sysctl: make NUMA stats configurable 2017-11-15 18:21:07 -08:00
workingset.c mm, truncate: do not check mapping for every page being truncated 2017-11-15 18:21:06 -08:00
z3fold.c mm: docs: fix parameter names mismatch 2018-02-06 18:32:48 -08:00
zbud.c mm: docs: fix parameter names mismatch 2018-02-06 18:32:48 -08:00
zpool.c mm/zpool.c: zpool_evictable: fix mismatch in parameter name and kernel-doc 2018-02-21 15:35:43 -08:00
zsmalloc.c zsmalloc: use U suffix for negative literals being shifted 2018-01-31 17:18:39 -08:00
zswap.c mm, swap, frontswap: fix THP swap if frontswap enabled 2018-02-21 15:35:43 -08:00