| From | Paul Gortmaker <> | Subject | [v2.6.34-stable 102/213] mm: bugfix: set current->reclaim_state to NULL while returning from kswapd() | Date | Wed, 5 Feb 2014 15:00:57 -0500 |
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From: Takamori Yamaguchi <takamori.yamaguchi@jp.sony.com>
------------------- This is a commit scheduled for the next v2.6.34 longterm release. http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git If you see a problem with using this for longterm, please comment. -------------------
commit b0a8cc58e6b9aaae3045752059e5e6260c0b94bc upstream.
In kswapd(), set current->reclaim_state to NULL before returning, as current->reclaim_state holds reference to variable on kswapd()'s stack.
In rare cases, while returning from kswapd() during memory offlining, __free_slab() and freepages() can access the dangling pointer of current->reclaim_state.
Signed-off-by: Takamori Yamaguchi <takamori.yamaguchi@jp.sony.com> Signed-off-by: Aaditya Kumar <aaditya.kumar@ap.sony.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> --- mm/vmscan.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/mm/vmscan.c b/mm/vmscan.c index 5c4620600333..365a899bcae0 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2341,6 +2341,8 @@ static int kswapd(void *p) if (!ret) balance_pgdat(pgdat, order); } + + current->reclaim_state = NULL; return 0; } -- 1.8.5.2
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