Re: [PATCH] mm: fix null pointer dereference in wait_iff_congested()
From: Sedat Dilek <hidden>
Date: 2012-12-29 08:45:32
Also in:
lkml
Just FYI: This patch landed upstream [1]. Thanks for all involved people. - Sedat - [1] http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=commitdiff;h=ecccd1248d6e6986130ffcc3b0d003cb46a485c0 On Fri, Dec 28, 2012 at 3:16 AM, Zlatko Calusic [off-list ref] wrote:
quoted hunk ↗ jump to hunk
From: Zlatko Calusic <redacted> The unintended consequence of commit 4ae0a48b is that wait_iff_congested() can now be called with NULL struct zone* producing kernel oops like this: BUG: unable to handle kernel NULL pointer dereference IP: [<ffffffff811542d9>] wait_iff_congested+0x59/0x140 This trivial patch fixes it. Reported-by: Zhouping Liu <redacted> Reported-and-tested-by: Sedat Dilek <redacted> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Zlatko Calusic <redacted> --- mm/vmscan.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)diff --git a/mm/vmscan.c b/mm/vmscan.c index 02bcfa3..e55ce55 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c@@ -2782,7 +2782,7 @@ loop_again: if (total_scanned && (sc.priority < DEF_PRIORITY - 2)) { if (has_under_min_watermark_zone) count_vm_event(KSWAPD_SKIP_CONGESTION_WAIT); - else + else if (unbalanced_zone) wait_iff_congested(unbalanced_zone, BLK_RW_ASYNC, HZ/10); } --1.8.1.rc3 -- Zlatko
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