The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 96c804a6ae8c59a9092b3d5dd581198472063184 Mon Sep 17 00:00:00 2001

From: David Hildenbrand david@redhat.com Date: Fri, 18 Oct 2019 20:19:23 -0700 Subject: [PATCH] mm/memory-failure.c: don't access uninitialized memmaps in memory_failure()

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: f1dd2cd13c4b ("mm, memory_hotplug: do not associate hotadded memory to zones until online") [visible after d0dc12e86b319] 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

diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 0ae72b6acee7..3151c87dff73 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1257,17 +1257,19 @@ 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)) {