This is a note to let you know that I've just added the patch titled mm/thp: do not wait for lock_page() in deferred_split_scan() to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: mm-thp-do-not-wait-for-lock_page-in-deferred_split_scan.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From fa41b900c30b45fab03783724932dc30cd46a6be Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx> Date: Thu, 22 Mar 2018 16:17:31 -0700 Subject: mm/thp: do not wait for lock_page() in deferred_split_scan() From: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> commit fa41b900c30b45fab03783724932dc30cd46a6be upstream. deferred_split_scan() gets called from reclaim path. Waiting for page lock may lead to deadlock there. Replace lock_page() with trylock_page() and skip the page if we failed to lock it. We will get to the page on the next scan. Link: http://lkml.kernel.org/r/20180315150747.31945-1-kirill.shutemov@xxxxxxxxxxxxxxx Fixes: 9a982250f773 ("thp: introduce deferred_split_huge_page()") Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- mm/huge_memory.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2739,11 +2739,13 @@ static unsigned long deferred_split_scan list_for_each_safe(pos, next, &list) { page = list_entry((void *)pos, struct page, mapping); - lock_page(page); + if (!trylock_page(page)) + goto next; /* split_huge_page() removes page from list on success */ if (!split_huge_page(page)) split++; unlock_page(page); +next: put_page(page); } Patches currently in stable-queue which might be from kirill.shutemov@xxxxxxxxxxxxxxx are queue-4.14/mm-khugepaged.c-convert-vm_bug_on-to-collapse-fail.patch queue-4.14/mm-thp-do-not-wait-for-lock_page-in-deferred_split_scan.patch queue-4.14/hugetlbfs-check-for-pgoff-value-overflow.patch queue-4.14/mm-shmem-do-not-wait-for-lock_page-in-shmem_unused_huge_shrink.patch