| From | Greg Kroah-Hartman <> | Subject | [ 001/171] mm: bugfix: set current->reclaim_state to NULL while returning from kswapd() | Date | Wed, 21 Nov 2012 16:39:07 -0800 |
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3.4-stable review patch. If anyone has any objections, please let me know.
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From: Takamori Yamaguchi <takamori.yamaguchi@jp.sony.com>
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- mm/vmscan.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -3128,6 +3128,8 @@ static int kswapd(void *p) &balanced_classzone_idx); } } + + current->reclaim_state = NULL; return 0; }
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