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authorMel Gorman <mgorman@techsingularity.net>2017-08-31 16:15:30 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-08-31 16:33:15 -0700
commitc461ad6a63b37ba74632e90c063d14823c884247 (patch)
tree8f6a60e6b4f5fed6209df79d090de5d2d0164f85
parent355627f518978b5167256d27492fe0b343aaf2f2 (diff)
mm, madvise: ensure poisoned pages are removed from per-cpu lists
Wendy Wang reported off-list that a RAS HWPOISON-SOFT test case failed and bisected it to the commit 479f854a207c ("mm, page_alloc: defer debugging checks of pages allocated from the PCP"). The problem is that a page that was poisoned with madvise() is reused. The commit removed a check that would trigger if DEBUG_VM was enabled but re-enabling the check only fixes the problem as a side-effect by printing a bad_page warning and recovering. The root of the problem is that an madvise() can leave a poisoned page on the per-cpu list. This patch drains all per-cpu lists after pages are poisoned so that they will not be reused. Wendy reports that the test case in question passes with this patch applied. While this could be done in a targeted fashion, it is over-complicated for such a rare operation. Link: http://lkml.kernel.org/r/20170828133414.7qro57jbepdcyz5x@techsingularity.net Fixes: 479f854a207c ("mm, page_alloc: defer debugging checks of pages allocated from the PCP") Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reported-by: Wang, Wendy <wendy.wang@intel.com> Tested-by: Wang, Wendy <wendy.wang@intel.com> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: "Hansen, Dave" <dave.hansen@intel.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Naoya Horiguchi <nao.horiguchi@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/madvise.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/mm/madvise.c b/mm/madvise.c
index 23ed525bc2bc..4d7d1e5ddba9 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -613,6 +613,7 @@ static int madvise_inject_error(int behavior,
unsigned long start, unsigned long end)
{
struct page *page;
+ struct zone *zone;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
@@ -646,6 +647,11 @@ static int madvise_inject_error(int behavior,
if (ret)
return ret;
}
+
+ /* Ensure that all poisoned pages are removed from per-cpu lists */
+ for_each_populated_zone(zone)
+ drain_all_pages(zone);
+
return 0;
}
#endif