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authorMel Gorman <mgorman@techsingularity.net>2017-08-31 16:15:30 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-09-07 08:35:39 +0200
commit8cc3acff5f1a99b153146643c6dd322edef11e21 (patch)
treecc9000a8a7c07000e64231978afdc54b40145525 /mm
parent17c564f629f436fb357b88398e1834f442c28ced (diff)
mm, madvise: ensure poisoned pages are removed from per-cpu lists
commit c461ad6a63b37ba74632e90c063d14823c884247 upstream. 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> 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>
Diffstat (limited to 'mm')
-rw-r--r--mm/madvise.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/mm/madvise.c b/mm/madvise.c
index 63a12162f4c6..55f30ec32e5b 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -533,6 +533,8 @@ static long madvise_remove(struct vm_area_struct *vma,
static int madvise_hwpoison(int bhv, unsigned long start, unsigned long end)
{
struct page *p;
+ struct zone *zone;
+
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
for (; start < end; start += PAGE_SIZE <<
@@ -561,6 +563,11 @@ static int madvise_hwpoison(int bhv, unsigned long start, unsigned long end)
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