diff options
| author | Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> | 2012-10-08 16:33:47 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-10-09 16:23:00 +0900 |
| commit | 7a71932d5676b7410ab64d149bad8bde6b0d8632 (patch) | |
| tree | bbe2b908dfcc7f5f8924e9cfc0fe0a49501d9a28 /fs/proc/page.c | |
| parent | cd8ed2a45a401cb692d769e92de7d73aa42fabce (diff) | |
| download | lwn-7a71932d5676b7410ab64d149bad8bde6b0d8632.tar.gz lwn-7a71932d5676b7410ab64d149bad8bde6b0d8632.zip | |
kpageflags: fix wrong KPF_THP on non-huge compound pages
KPF_THP can be set on non-huge compound pages (like slab pages or pages
allocated by drivers with __GFP_COMP) because PageTransCompound only
checks PG_head and PG_tail. Obviously this is a bug and breaks user space
applications which look for thp via /proc/kpageflags.
This patch rules out setting KPF_THP wrongly by additionally checking
PageLRU on the head pages.
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: David Rientjes <rientjes@google.com>
Reviewed-by: Fengguang Wu <fengguang.wu@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/proc/page.c')
| -rw-r--r-- | fs/proc/page.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/fs/proc/page.c b/fs/proc/page.c index 7fcd0d60a968..b8730d9ebaee 100644 --- a/fs/proc/page.c +++ b/fs/proc/page.c @@ -115,7 +115,13 @@ u64 stable_page_flags(struct page *page) u |= 1 << KPF_COMPOUND_TAIL; if (PageHuge(page)) u |= 1 << KPF_HUGE; - else if (PageTransCompound(page)) + /* + * PageTransCompound can be true for non-huge compound pages (slab + * pages or pages allocated by drivers with __GFP_COMP) because it + * just checks PG_head/PG_tail, so we need to check PageLRU to make + * sure a given page is a thp, not a non-huge compound page. + */ + else if (PageTransCompound(page) && PageLRU(compound_trans_head(page))) u |= 1 << KPF_THP; /* |