The patch titled
Subject: squashfs: fix page update race
has been added to the -mm mm-nonmm-unstable branch. Its filename is
squashfs-cache-partial-compressed-blocks-fix-2.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/squashfs-cache-partial-compressed-blocks-fix-2.patch
This patch will later appear in the mm-nonmm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Vincent Whitchurch <vincent.whitchurch@xxxxxxxx>
Subject: squashfs: fix page update race
Date: Fri, 26 May 2023 15:25:45 +0200
We only put the page into the cache after we've read it, so the
PageUptodate() check should not be necessary. In fact, it's actively
harmful since the check could fail (since we used find_get_page() and not
find_lock_page()) and we could end up submitting a page for I/O after it
has been read and while it's actively being used, which could lead to
corruption depending on what the block driver does with it.
Link: https://lkml.kernel.org/r/20230526-squashfs-cache-fixup-v1-1-d54a7fa23e7b@xxxxxxxx
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@xxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Phillip Lougher <phillip@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/squashfs/block.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/squashfs/block.c~squashfs-cache-partial-compressed-blocks-fix-2
+++ a/fs/squashfs/block.c
@@ -92,7 +92,7 @@ static int squashfs_bio_read_cached(stru
bio_for_each_segment_all(bv, fullbio, iter_all) {
struct page *page = bv->bv_page;
- if (page->mapping == cache_mapping && PageUptodate(page)) {
+ if (page->mapping == cache_mapping) {
idx++;
continue;
}
_
Patches currently in -mm which might be from vincent.whitchurch@xxxxxxxx are
squashfs-cache-partial-compressed-blocks.patch
squashfs-cache-partial-compressed-blocks-fix-2.patch
squashfs-cache-partial-compressed-blocks-fix-3.patch
