Running LTP oom01 in a tight loop or memory stress testing put the
system in a low-memory situation could triggers random memory
corruption like page flag corruption below due to in
fast_isolate_freepages(), if isolation fails, next_search_order() does
not abort the search immediately could lead to improper accesses.
UBSAN: Undefined behaviour in ./include/linux/mm.h:1195:50
index 7 is out of range for type 'zone [5]'
Call Trace:
dump_stack+0x62/0x9a
ubsan_epilogue+0xd/0x7f
__ubsan_handle_out_of_bounds+0x14d/0x192
__isolate_free_page+0x52c/0x600
compaction_alloc+0x886/0x25f0
unmap_and_move+0x37/0x1e70
migrate_pages+0x2ca/0xb20
compact_zone+0x19cb/0x3620
kcompactd_do_work+0x2df/0x680
kcompactd+0x1d8/0x6c0
kthread+0x32c/0x3f0
ret_from_fork+0x35/0x40
------------[ cut here ]------------
kernel BUG at mm/page_alloc.c:3124!
invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN PTI
RIP: 0010:__isolate_free_page+0x464/0x600
RSP: 0000:ffff888b9e1af848 EFLAGS: 00010007
RAX: 0000000030000000 RBX: ffff888c39fcf0f8 RCX: 0000000000000000
RDX: 1ffff111873f9e25 RSI: 0000000000000004 RDI: ffffed1173c35ef6
RBP: ffff888b9e1af898 R08: fffffbfff4fc2461 R09: fffffbfff4fc2460
R10: fffffbfff4fc2460 R11: ffffffffa7e12303 R12: 0000000000000008
R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000007
FS: 0000000000000000(0000) GS:ffff888ba8e80000(0000)
knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc7abc00000 CR3: 0000000752416004 CR4: 00000000001606a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
compaction_alloc+0x886/0x25f0
unmap_and_move+0x37/0x1e70
migrate_pages+0x2ca/0xb20
compact_zone+0x19cb/0x3620
kcompactd_do_work+0x2df/0x680
kcompactd+0x1d8/0x6c0
kthread+0x32c/0x3f0
ret_from_fork+0x35/0x40
Fixes: dbe2d4e4f12e ("mm, compaction: round-robin the order while searching the
free lists for a target")
Signed-off-by: Qian Cai <c...@lca.pw>
---
mm/compaction.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/mm/compaction.c b/mm/compaction.c
index 6aebf1eb8d98..41cec13c4c9c 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1245,6 +1245,10 @@ fast_isolate_around(struct compact_control *cc, unsigned
long pfn, unsigned long
/* Search orders in round-robin fashion */
static int next_search_order(struct compact_control *cc, int order)
{
+ /* If isolation fails, abort the search. */
+ if (order == -1)
+ return -1;
+
order--;
if (order < 0)
order = cc->order - 1;
--
2.17.2 (Apple Git-113)
