Messages in this thread Patch in this message | | | From | Andi Kleen <> | Subject | [PATCH] hwpoison: Fix race with changing page during offlining v2 | Date | Mon, 30 Jun 2014 17:32:16 -0700 |
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From: Andi Kleen <ak@linux.intel.com>
When a hwpoison page is locked it could change state due to parallel modifications. Check after the lock if the page is still the same compound page.
[v2: Removed earlier non LRU check which should be already covered elsewhere]
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andi Kleen <ak@linux.intel.com> --- mm/memory-failure.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
diff --git a/mm/memory-failure.c b/mm/memory-failure.c index cd8989c..99e5077 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1168,6 +1168,16 @@ int memory_failure(unsigned long pfn, int trapno, int flags) lock_page(hpage); /* + * The page could have changed compound pages during the locking. + * If this happens just bail out. + */ + if (compound_head(p) != hpage) { + action_result(pfn, "different compound page after locking", IGNORED); + res = -EBUSY; + goto out; + } + + /* * We use page flags to determine what action should be taken, but * the flags can be modified by the error containment action. One * example is an mlocked page, where PG_mlocked is cleared by -- 1.9.3
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