linux/mm
Vlastimil Babka 78f20db864 mm: fix classzone_idx underflow in shrink_zones()
[Not upstream as that would take 34+ patches]

We've got reported a BUG in do_try_to_free_pages():

BUG: unable to handle kernel paging request at ffff8ffffff28990
IP: [<ffffffff8119abe0>] do_try_to_free_pages+0x140/0x490
PGD 0
Oops: 0000 [#1] SMP
megaraid_sas sg scsi_mod efivarfs autofs4
Supported: No, Unsupported modules are loaded
Workqueue: kacpi_hotplug acpi_hotplug_work_fn
task: ffff88ffd0d4c540 ti: ffff88ffd0e48000 task.ti: ffff88ffd0e48000
RIP: 0010:[<ffffffff8119abe0>]  [<ffffffff8119abe0>] do_try_to_free_pages+0x140/0x490
RSP: 0018:ffff88ffd0e4ba60  EFLAGS: 00010206
RAX: 000006fffffff900 RBX: 00000000ffffffff RCX: ffff88fffff29000
RDX: 000000ffffffff00 RSI: 0000000000000003 RDI: 00000000024200c8
RBP: 0000000001320122 R08: 0000000000000000 R09: ffff88ffd0e4bbac
R10: 0000000000000000 R11: 0000000000000000 R12: ffff88ffd0e4bae0
R13: 0000000000000e00 R14: ffff88fffff2a500 R15: ffff88fffff2b300
FS:  0000000000000000(0000) GS:ffff88ffe6440000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff8ffffff28990 CR3: 0000000001c0a000 CR4: 00000000003406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 00000002db570a80 024200c80000001e ffff88fffff2b300 0000000000000000
 ffff88fffffd5700 ffff88ffd0d4c540 ffff88ffd0d4c540 ffffffff0000000c
 0000000000000000 0000000000000040 00000000024200c8 ffff88ffd0e4bae0
Call Trace:
 [<ffffffff8119afea>] try_to_free_pages+0xba/0x170
 [<ffffffff8118cf2f>] __alloc_pages_nodemask+0x53f/0xb20
 [<ffffffff811d39ff>] alloc_pages_current+0x7f/0x100
 [<ffffffff811e2232>] migrate_pages+0x202/0x710
 [<ffffffff815dadaa>] __offline_pages.constprop.23+0x4ba/0x790
 [<ffffffff81463263>] memory_subsys_offline+0x43/0x70
 [<ffffffff8144cbed>] device_offline+0x7d/0xa0
 [<ffffffff81392fa2>] acpi_bus_offline+0xa5/0xef
 [<ffffffff81394a77>] acpi_device_hotplug+0x21b/0x41f
 [<ffffffff8138dab7>] acpi_hotplug_work_fn+0x1a/0x23
 [<ffffffff81093cee>] process_one_work+0x14e/0x410
 [<ffffffff81094546>] worker_thread+0x116/0x490
 [<ffffffff810999ed>] kthread+0xbd/0xe0
 [<ffffffff815e4e7f>] ret_from_fork+0x3f/0x70

This translates to the loop in shrink_zone():

classzone_idx = requested_highidx;
while (!populated_zone(zone->zone_pgdat->node_zones +
					classzone_idx))
	classzone_idx--;

where no zone is populated, so classzone_idx becomes -1 (in RBX).

Added debugging output reveals that we enter the function with
sc->gfp_mask == GFP_NOFS|__GFP_NOFAIL|__GFP_HARDWALL|__GFP_MOVABLE
requested_highidx = gfp_zone(sc->gfp_mask) == 2 (ZONE_NORMAL)

Inside the for loop, however:
gfp_zone(sc->gfp_mask) == 3 (ZONE_MOVABLE)

This means we have gone through this branch:

if (buffer_heads_over_limit)
    sc->gfp_mask |= __GFP_HIGHMEM;

This changes the gfp_zone() result, but requested_highidx remains unchanged.
On nodes where the only populated zone is movable, the inner while loop will
check only lower zones, which are not populated, and underflow classzone_idx.

To sum up, the bug occurs in configurations with ZONE_MOVABLE (such as when
booted with the movable_node parameter) and only in situations when
buffer_heads_over_limit is true, and there's an allocation with __GFP_MOVABLE
and without __GFP_HIGHMEM performing direct reclaim.

This patch makes sure that classzone_idx starts with the correct zone.

Mainline has been affected in versions 4.6 and 4.7, but the culprit commit has
been also included in stable trees.
In mainline, this has been fixed accidentally as part of 34-patch series (plus
follow-up fixes) "Move LRU page reclaim from zones to nodes", which makes the
mainline commit unsuitable for stable backport, unfortunately.

Fixes: 7bf52fb891 ("mm: vmscan: reclaim highmem zone if buffer_heads is over limit")
Obsoleted-by: b2e18757f2 ("mm, vmscan: begin reclaiming pages on a per-node basis")
Debugged-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-07-15 11:57:44 +02:00
..
kasan kasan: respect /proc/sys/kernel/traceoff_on_warning 2017-06-17 06:39:36 +02:00
backing-dev.c block: fix double-free in the failure path of cgwb_bdi_init() 2017-02-26 11:07:51 +01:00
balloon_compaction.c virtio_balloon: fix race between migration and ballooning 2016-03-03 15:07:18 -08:00
bootmem.c bootmem: avoid freeing to bootmem after bootmem is done 2015-09-08 15:35:28 -07:00
cleancache.c cleancache: remove limit on the number of cleancache enabled filesystems 2015-04-14 16:49:03 -07:00
cma_debug.c mm/cma_debug: correct size input to bitmap function 2015-07-17 16:39:54 -07:00
cma.c mm/cma: silence warnings due to max() usage 2016-11-10 16:36:36 +01:00
cma.h mm: cma: mark cma_bitmap_maxno() inline in header 2015-08-14 15:56:32 -07:00
compaction.c mm, compaction: prevent VM_BUG_ON when terminating freeing scanner 2016-08-10 11:49:25 +02:00
debug-pagealloc.c mm/debug-pagealloc: make debug-pagealloc boottime configurable 2014-12-13 12:42:48 -08:00
debug.c mm: make compound_head() robust 2015-11-06 17:50:42 -08:00
dmapool.c mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd 2015-11-06 17:50:42 -08:00
early_ioremap.c mm/early_ioremap: use offset_in_page macro 2015-11-05 19:34:48 -08:00
fadvise.c writeback: implement and use inode_congested() 2015-06-02 08:33:35 -06:00
failslab.c mm, page_alloc: rename __GFP_WAIT to __GFP_RECLAIM 2015-11-06 17:50:42 -08:00
filemap.c mm: do not access page->mapping directly on page_endio 2017-03-12 06:37:25 +01:00
frame_vector.c mm: fix docbook comment for get_vaddr_frames() 2015-11-05 19:34:48 -08:00
frontswap.c frontswap: allow multiple backends 2015-06-24 17:49:45 -07:00
gup.c mm: larger stack guard gap, between vmas 2017-06-26 07:13:11 +02:00
highmem.c mm/highmem: make kmap cache coloring aware 2014-08-06 18:01:22 -07:00
huge_memory.c mm: numa: avoid waiting on freed migrated pages 2017-07-05 14:37:16 +02:00
hugetlb_cgroup.c mm: make compound_head() robust 2015-11-06 17:50:42 -08:00
hugetlb.c mm, hugetlb: use pte_present() instead of pmd_present() in follow_huge_pmd() 2017-04-08 09:53:32 +02:00
hwpoison-inject.c hwpoison: use page_cgroup_ino for filtering by memcg 2015-09-10 13:29:01 -07:00
init-mm.c mm: Add a user_ns owner to mm_struct and fix ptrace permission checks 2017-01-06 11:16:11 +01:00
internal.h mm, sl[au]b: add __GFP_ATOMIC to the GFP reclaim mask 2016-08-10 11:49:25 +02:00
interval_tree.c mm: replace vma->sharead.linear with vma->shared 2015-02-10 14:30:31 -08:00
Kconfig mm: make compound_head() robust 2015-11-06 17:50:42 -08:00
Kconfig.debug mm/debug_pagealloc: remove obsolete Kconfig options 2015-01-08 15:10:52 -08:00
kmemcheck.c mm/slab_common: move kmem_cache definition to internal header 2014-10-09 22:25:50 -04:00
kmemleak-test.c mm/kmemleak-test.c: use pr_fmt for logging 2014-06-06 16:08:18 -07:00
kmemleak.c mm/kmemleak.c: remove unneeded initialization of object to NULL 2015-11-05 19:34:48 -08:00
ksm.c mm,ksm: fix endless looping in allocating memory when ksm enable 2016-10-07 15:23:40 +02:00
list_lru.c mm/list_lru.c: avoid error-path NULL pointer deref 2016-11-10 16:36:32 +01:00
maccess.c mm/maccess.c: actually return -EFAULT from strncpy_from_unsafe 2015-11-05 19:34:48 -08:00
madvise.c mm: madvise allow remove operation for hugetlbfs 2015-09-08 15:35:28 -07:00
Makefile media updates for v4.3-rc1 2015-09-11 16:42:39 -07:00
memblock.c mm: consider memblock reservations for deferred memory initialization sizing 2017-06-14 13:16:26 +02:00
memcontrol.c mm: memcontrol: avoid unused function warning 2017-03-18 19:09:57 +08:00
memory_hotplug.c base/memory, hotplug: fix a kernel oops in show_valid_zones() 2017-02-09 08:02:47 +01:00
memory-failure.c mm/memory-failure.c: use compound_head() flags for huge pages 2017-06-26 07:13:10 +02:00
memory.c mm: larger stack guard gap, between vmas 2017-06-26 07:13:11 +02:00
mempolicy.c mm/mempolicy.c: fix error handling in set_mempolicy and mbind. 2017-04-12 12:38:35 +02:00
mempool.c mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd 2015-11-06 17:50:42 -08:00
memtest.c memtest: remove unused header files 2015-09-08 15:35:28 -07:00
migrate.c mm: Export migrate_page_move_mapping and migrate_page_copy 2016-07-27 09:47:31 -07:00
mincore.c mm/mincore: use offset_in_page macro 2015-11-05 19:34:48 -08:00
mlock.c mlock: fix mlock count can not decrease in race condition 2017-06-07 12:06:01 +02:00
mm_init.c mm: meminit: remove mminit_verify_page_links 2015-06-30 19:44:56 -07:00
mmap.c mm: fix new crash in unmapped_area_topdown() 2017-06-26 07:13:11 +02:00
mmu_context.c sched/mm: call finish_arch_post_lock_switch in idle_task_exit and use_mm 2014-02-21 08:50:17 +01:00
mmu_notifier.c mmu-notifier: add clear_young callback 2015-09-10 13:29:01 -07:00
mmzone.c mm: microoptimize zonelist operations 2015-02-11 17:06:02 -08:00
mprotect.c userfaultfd: teach vma_merge to merge across vma->vm_userfaultfd_ctx 2015-09-04 16:54:41 -07:00
mremap.c mm/mremap: use offset_in_page macro 2015-11-05 19:34:48 -08:00
msync.c mm/msync: use offset_in_page macro 2015-11-05 19:34:48 -08:00
nobootmem.c mm: page_alloc: pass PFN to __free_pages_bootmem 2015-06-30 19:44:55 -07:00
nommu.c mm/nommu.c: drop unlikely inside BUG_ON() 2015-11-05 19:34:48 -08:00
oom_kill.c mm/oom_kill.c: avoid attempting to kill init sharing same memory 2015-12-12 10:15:34 -08:00
page_alloc.c mm: consider memblock reservations for deferred memory initialization sizing 2017-06-14 13:16:26 +02:00
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: introduce idle page tracking 2015-09-10 13:29:01 -07:00
page_idle.c mm: introduce idle page tracking 2015-09-10 13:29:01 -07:00
page_io.c fs: use helper bio_add_page() instead of open coding on bi_io_vec 2015-08-13 12:32:00 -06:00
page_isolation.c mm: fix invalid node in alloc_migrate_target() 2016-04-20 15:41:53 +09:00
page_owner.c mm/page_owner: set correct gfp_mask on page_owner 2015-07-17 16:39:54 -07:00
page-writeback.c writeback: use higher precision calculation in domain_dirty_limits() 2016-07-27 09:47:29 -07:00
pagewalk.c mm/pagewalk.c: prevent positive return value of walk_page_test() from being passed to callers 2015-03-25 16:20:30 -07:00
percpu-km.c percpu: implmeent pcpu_nr_empty_pop_pages and chunk->nr_populated 2014-09-02 14:46:05 -04:00
percpu-vm.c percpu: move region iterations out of pcpu_[de]populate_chunk() 2014-09-02 14:46:02 -04:00
percpu.c percpu: acquire pcpu_lock when updating pcpu_nr_empty_pop_pages 2017-03-26 12:13:20 +02:00
pgtable-generic.c mm,thp: khugepaged: call pte flush at the time of collapse 2016-02-25 12:01:23 -08:00
process_vm_access.c ptrace: use fsuid, fsgid, effective creds for fs access checks 2016-02-25 12:01:16 -08:00
quicklist.c
readahead.c mm, fs: introduce mapping_gfp_constraint() 2015-11-06 17:50:42 -08:00
rmap.c mm: page migration use migration entry for swapcache too 2015-11-05 19:34:48 -08:00
shmem.c tmpfs: fix regression hang in fallocate undo 2016-07-27 09:47:40 -07:00
slab_common.c mm: memcontrol: fix cgroup creation failure after many small jobs 2016-08-16 09:30:51 +02:00
slab.c slab/slub: adjust kmem_cache_alloc_bulk API 2015-11-22 11:58:44 -08:00
slab.h slab/slub: adjust kmem_cache_alloc_bulk API 2015-11-22 11:58:44 -08:00
slob.c slab/slub: adjust kmem_cache_alloc_bulk API 2015-11-22 11:58:44 -08:00
slub.c slub/memcg: cure the brainless abuse of sysfs attributes 2017-06-07 12:06:01 +02:00
sparse-vmemmap.c mm/sparse: use memblock apis for early memory allocations 2014-01-21 16:19:47 -08:00
sparse.c mm: use macros from compiler.h instead of __attribute__((...)) 2014-04-07 16:35:54 -07:00
swap_cgroup.c mm, swap_cgroup: reschedule when neeed in swap_cgroup_swapoff() 2017-07-05 14:37:15 +02:00
swap_state.c mm: swap: zswap: maybe_preload & refactoring 2015-09-08 15:35:28 -07:00
swap.c mm: make compound_head() robust 2015-11-06 17:50:42 -08:00
swapfile.c swapfile: fix memory corruption via malformed swapfile 2016-11-18 10:48:34 +01:00
truncate.c fs: add i_blocksize() 2017-06-14 13:16:24 +02:00
userfaultfd.c userfaultfd: avoid mmap_sem read recursion in mcopy_atomic 2015-09-04 16:54:41 -07:00
util.c proc: revert /proc/<pid>/maps [stack:TID] annotation 2016-09-15 08:27:46 +02:00
vmacache.c mm/vmacache: inline vmacache_valid_mm() 2015-11-05 19:34:48 -08:00
vmalloc.c mm: vmalloc: don't remove inexistent guard hole in remove_vm_area() 2015-11-20 16:17:32 -08:00
vmpressure.c mm: vmpressure: fix sending wrong events on underflow 2017-03-12 06:37:25 +01:00
vmscan.c mm: fix classzone_idx underflow in shrink_zones() 2017-07-15 11:57:44 +02:00
vmstat.c vmstat: allocate vmstat_wq before it is used 2016-01-08 23:47:54 -08:00
workingset.c mm: workingset: fix crash in shadow node shrinker caused by replace_page_cache_page() 2016-10-28 03:01:34 -04:00
zbud.c mm: zsmalloc: constify struct zs_pool name 2015-11-06 17:50:42 -08:00
zpool.c mm: zsmalloc: constify struct zs_pool name 2015-11-06 17:50:42 -08:00
zsmalloc.c zsmalloc: fix zs_can_compact() integer overflow 2016-05-18 17:06:44 -07:00
zswap.c zswap: disable changing params if init fails 2017-02-09 08:02:45 +01:00