Re: [syzbot] [jfs?] UBSAN: shift-out-of-bounds in dbJoin (2)

Edward Adam Davis
2025-12-07T03:18:54Z

#syz test

diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c
index cdfa699cd7c8..7c35e69cafb9 100644
--- a/fs/jfs/jfs_dmap.c
+++ b/fs/jfs/jfs_dmap.c
@@ -2291,6 +2291,8 @@ static int dbFreeBits(struct bmap * bmp, struct dmap * dp, s64 blkno,
int rc = 0;
int size;

+ if (tp->dmt_budmin < 0)
+ return -EUCLEAN;
/* determine the bit number and word within the dmap of the
* starting block.
*/