Commit 8bcb74de authored May 03, 2017 by Naoya Horiguchi Committed by Linus Torvalds May 03, 2017

mm: hwpoison: call shake_page() unconditionally

shake_page() is called before going into core error handling code in
order to ensure that the error page is flushed from lru_cache lists
where pages stay during transferring among LRU lists.

But currently it's not fully functional because when the page is linked
to lru_cache by calling activate_page(), its PageLRU flag is set and
shake_page() is skipped.  The result is to fail error handling with
"still referenced by 1 users" message.

When the page is linked to lru_cache by isolate_lru_page(), its PageLRU
is clear, so that's fine.

This patch makes shake_page() unconditionally called to avoild the
failure.

Fixes: 23a003bf ("mm/madvise: pass return code of memory_failure() to userspace")
Link: http://lkml.kernel.org/r/20170417055948.GM31394@yexl-desktop
Link: http://lkml.kernel.org/r/1493197841-23986-2-git-send-email-n-horiguchi@ah.jp.nec.com


Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reported-by: kernel test robot <lkp@intel.com>
Cc: Xiaolong Ye <xiaolong.ye@intel.com>
Cc: Chen Gong <gong.chen@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 0ccfece6

mm/hwpoison-inject.c

+1 −2

Original line number	Diff line number	Diff line
		@@ -34,7 +34,6 @@ static int hwpoison_inject(void *data, u64 val)
		if (!hwpoison_filter_enable)
		goto inject;

		if (!PageLRU(hpage) && !PageHuge(p))
		shake_page(hpage, 0);
		/*
		* This implies unable to support non-LRU pages.

mm/memory-failure.c

+11 −16

Original line number	Diff line number	Diff line
		@@ -220,6 +220,9 @@ static int kill_proc(struct task_struct *t, unsigned long addr, int trapno,
		*/
		void shake_page(struct page *p, int access)
		{
		if (PageHuge(p))
		return;

		if (!PageSlab(p)) {
		lru_add_drain_all();
		if (PageLRU(p))
		@@ -1137,23 +1140,15 @@ int memory_failure(unsigned long pfn, int trapno, int flags)
		* The check (unnecessarily) ignores LRU pages being isolated and
		* walked by the page reclaim code, however that's not a big loss.
		*/
		if (!PageHuge(p)) {
		if (!PageLRU(p))
		shake_page(p, 0);
		if (!PageLRU(p)) {
		/*
		* shake_page could have turned it free.
		*/
		if (is_free_buddy_page(p)) {
		/* shake_page could have turned it free. */
		if (!PageLRU(p) && is_free_buddy_page(p)) {
		if (flags & MF_COUNT_INCREASED)
		action_result(pfn, MF_MSG_BUDDY, MF_DELAYED);
		else
		action_result(pfn, MF_MSG_BUDDY_2ND,
		MF_DELAYED);
		action_result(pfn, MF_MSG_BUDDY_2ND, MF_DELAYED);
		return 0;
		}
		}
		}

		lock_page(hpage);

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