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
