Commit 9792afbd authored Oct 18, 2019 by David Hildenbrand Committed by Greg Kroah-Hartman Oct 29, 2019

mm/memory-failure.c: don't access uninitialized memmaps in memory_failure()

commit 96c804a6ae8c59a9092b3d5dd581198472063184 upstream.

We should check for pfn_to_online_page() to not access uninitialized
memmaps.  Reshuffle the code so we don't have to duplicate the error
message.

Link: http://lkml.kernel.org/r/20191009142435.3975-3-david@redhat.com


Signed-off-by: David Hildenbrand <david@redhat.com>
Fixes: f1dd2cd1 ("mm, memory_hotplug: do not associate hotadded memory to zones until online")	[visible after d0dc12e8]
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: <stable@vger.kernel.org>	[4.13+]
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>

parent 01a44055

mm/memory-failure.c

+8 −6

Original line number	Diff line number	Diff line
		@@ -1258,17 +1258,19 @@ int memory_failure(unsigned long pfn, int flags)
		if (!sysctl_memory_failure_recovery)
		panic("Memory failure on page %lx", pfn);

		if (!pfn_valid(pfn)) {
		p = pfn_to_online_page(pfn);
		if (!p) {
		if (pfn_valid(pfn)) {
		pgmap = get_dev_pagemap(pfn, NULL);
		if (pgmap)
		return memory_failure_dev_pagemap(pfn, flags,
		pgmap);
		}
		pr_err("Memory failure: %#lx: memory outside kernel control\n",
		pfn);
		return -ENXIO;
		}

		pgmap = get_dev_pagemap(pfn, NULL);
		if (pgmap)
		return memory_failure_dev_pagemap(pfn, flags, pgmap);

		p = pfn_to_page(pfn);
		if (PageHuge(p))
		return memory_failure_hugetlb(pfn, flags);
		if (TestSetPageHWPoison(p)) {