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| author | OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> | 2020-08-11 18:36:01 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-08-12 10:58:01 -0700 |
| commit | a090a5a7d73f79a9ae2dcc6e60d89bfc6864a65a (patch) | |
| tree | 28512bf55a2f7984d183e4738b974d1fc7414ba1 | |
| parent | 4ecfed61de766f4655025a71d79c9a0f4793a3f4 (diff) | |
| download | memblock-a090a5a7d73f79a9ae2dcc6e60d89bfc6864a65a.tar.gz | |
fat: fix fat_ra_init() for data clusters == 0
If data clusters == 0, fat_ra_init() calls the ->ent_blocknr() for the
cluster beyond ->max_clusters.
This checks the limit before initialization to suppress the warning.
Reported-by: syzbot+756199124937b31a9b7e@syzkaller.appspotmail.com
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/87mu462sv4.fsf@mail.parknet.co.jp
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | fs/fat/fatent.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/fat/fatent.c b/fs/fat/fatent.c index bbfe18c0741795..f7e3304b78029f 100644 --- a/fs/fat/fatent.c +++ b/fs/fat/fatent.c @@ -657,6 +657,9 @@ static void fat_ra_init(struct super_block *sb, struct fatent_ra *ra, unsigned long ra_pages = sb->s_bdi->ra_pages; unsigned int reada_blocks; + if (fatent->entry >= ent_limit) + return; + if (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); |