The patch titled Subject: fat: avoid oops when bdi->io_pages==0 has been added to the -mm tree. Its filename is fat-avoid-oops-when-bdi-io_pages==0.patch

This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/fat-avoid-oops-when-bdi-io_pages%3D... and later at http://ozlabs.org/~akpm/mmotm/broken-out/fat-avoid-oops-when-bdi-io_pages%3D...

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 and is updated there every 3-4 working days

------------------------------------------------------ From: OGAWA Hirofumi hirofumi@mail.parknet.co.jp Subject: fat: avoid oops when bdi->io_pages==0

On one system, there was bdi->io_pages==0. This seems to be the bug of a driver somewhere, which perhaps failed to initialize io_pages. We should fix it though - it is better to avoid the divide-by-zero Oops.

So add a check for this.

Link: http://lkml.kernel.org/r/87ft85osn6.fsf@mail.parknet.co.jp Signed-off-by: OGAWA Hirofumi hirofumi@mail.parknet.co.jp Cc: Matthew Wilcox willy@infradead.org Cc: Jens Axboe axboe@kernel.dk Cc: stable@vger.kernel.org [5.8+] Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

fs/fat/fatent.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/fat/fatent.c~fat-avoid-oops-when-bdi-io_pages==0 +++ a/fs/fat/fatent.c @@ -660,7 +660,7 @@ static void fat_ra_init(struct super_blo if (fatent->entry >= ent_limit) return;

- if (ra_pages > sb->s_bdi->io_pages) + if (sb->s_bdi->io_pages && ra_pages > sb->s_bdi->io_pages) ra_pages = rounddown(ra_pages, sb->s_bdi->io_pages); reada_blocks = ra_pages << (PAGE_SHIFT - sb->s_blocksize_bits + 1);

_

Patches currently in -mm which might be from hirofumi@mail.parknet.co.jp are

fat-avoid-oops-when-bdi-io_pages==0.patch