MM/compaction patches for 5.1-rc4

The merge window for 5.1 introduced a number of compaction-related patches.
with intermittent reports of corruption and functional issues. The bugs
are due to sloopy checking of zone boundaries and a corner case where
invalid indexes are used to access the free lists.

Reports are not common but at least two users and 0-day have tripped
over them.  There is a chance that one of the syzbot reports are related
but it has not been confirmed properly.

The normal submission path is with Andrew but there have been some delays
and I consider them urgent enough that they should be picked up before
RC4 to avoid duplicate reports.

All of these have been successfully tested on older RC windows. This
will make this branch look like a rebase but in fact, they've simply
been lifted again from Andrew's tree and placed on a fresh branch. I've
no reason to believe that this has invalidated the testing given the
lack of change in compaction and the nature of the fixes.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
mm/compaction.c: abort search if isolation fails

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

Link: http://lkml.kernel.org/r/20190320192648.52499-1-cai@lca.pw
Fixes: dbe2d4e4f12e ("mm, compaction: round-robin the order while searching the free lists for a target")
Signed-off-by: Qian Cai <cai@lca.pw>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
1 file changed