This is a note to let you know that I've just added the patch titled mm/filemap.c: remove bogus VM_BUG_ON to the 5.14-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-filemap.c-remove-bogus-vm_bug_on.patch and it can be found in the queue-5.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From d417b49fff3e2f21043c834841e8623a6098741d Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx> Date: Fri, 5 Nov 2021 13:37:10 -0700 Subject: mm/filemap.c: remove bogus VM_BUG_ON From: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> commit d417b49fff3e2f21043c834841e8623a6098741d upstream. It is not safe to check page->index without holding the page lock. It can be changed if the page is moved between the swap cache and the page cache for a shmem file, for example. There is a VM_BUG_ON below which checks page->index is correct after taking the page lock. Link: https://lkml.kernel.org/r/20210818144932.940640-1-willy@xxxxxxxxxxxxx Fixes: 5c211ba29deb ("mm: add and use find_lock_entries") Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> Reported-by: <syzbot+c87be4f669d920c76330@xxxxxxxxxxxxxxxxxxxxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> 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/filemap.c | 1 - 1 file changed, 1 deletion(-) --- a/mm/filemap.c +++ b/mm/filemap.c @@ -2038,7 +2038,6 @@ unsigned find_lock_entries(struct addres if (!xa_is_value(page)) { if (page->index < start) goto put; - VM_BUG_ON_PAGE(page->index != xas.xa_index, page); if (page->index + thp_nr_pages(page) - 1 > end) goto put; if (!trylock_page(page)) Patches currently in stable-queue which might be from willy@xxxxxxxxxxxxx are queue-5.14/mm-filemap.c-remove-bogus-vm_bug_on.patch queue-5.14/arm64-pgtable-make-__pte_to_phys-__phys_to_pte_val-i.patch