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| author | Joonsoo Kim <js1304@gmail.com> | 2015-07-17 16:24:15 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-07-17 16:39:54 -0700 |
| commit | f3a14ced32513d103a3ed0ce89c4e713fac01461 (patch) | |
| tree | 77223d52fd790045da18f435987fb5199dcfa6d9 /mm | |
| parent | a2673b6e040663bf16a552f8619e6bde9f4b9acf (diff) | |
| download | lwn-f3a14ced32513d103a3ed0ce89c4e713fac01461.tar.gz lwn-f3a14ced32513d103a3ed0ce89c4e713fac01461.zip | |
mm/page_owner: fix possible access violation
When I tested my new patches, I found that page pointer which is used
for setting page_owner information is changed. This is because page
pointer is used to set new migratetype in loop. After this work, page
pointer could be out of bound. If this wrong pointer is used for
page_owner, access violation happens. Below is error message that I
got.
BUG: unable to handle kernel paging request at 0000000000b00018
IP: [<ffffffff81025f30>] save_stack_address+0x30/0x40
PGD 1af2d067 PUD 166e0067 PMD 0
Oops: 0002 [#1] SMP
...snip...
Call Trace:
print_context_stack+0xcf/0x100
dump_trace+0x15f/0x320
save_stack_trace+0x2f/0x50
__set_page_owner+0x46/0x70
__isolate_free_page+0x1f7/0x210
split_free_page+0x21/0xb0
isolate_freepages_block+0x1e2/0x410
compaction_alloc+0x22d/0x2d0
migrate_pages+0x289/0x8b0
compact_zone+0x409/0x880
compact_zone_order+0x6d/0x90
try_to_compact_pages+0x110/0x210
__alloc_pages_direct_compact+0x3d/0xe6
__alloc_pages_nodemask+0x6cd/0x9a0
alloc_pages_current+0x91/0x100
runtest_store+0x296/0xa50
simple_attr_write+0xbd/0xe0
__vfs_write+0x28/0xf0
vfs_write+0xa9/0x1b0
SyS_write+0x46/0xb0
system_call_fastpath+0x16/0x75
This patch fixes this error by moving up set_page_owner().
Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/page_alloc.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index ac05e7ae399e..fbba675a0bd9 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1994,6 +1994,8 @@ int __isolate_free_page(struct page *page, unsigned int order) zone->free_area[order].nr_free--; rmv_page_order(page); + set_page_owner(page, order, 0); + /* Set the pageblock if the isolated page is at least a pageblock */ if (order >= pageblock_order - 1) { struct page *endpage = page + (1 << order) - 1; @@ -2005,7 +2007,7 @@ int __isolate_free_page(struct page *page, unsigned int order) } } - set_page_owner(page, order, 0); + return 1UL << order; } |