From: Pei Li peili.dev@gmail.com
[ Upstream commit 7063b80268e2593e58bee8a8d709c2f3ff93e2f2 ]
When searching for the next smaller log2 block, BLKSTOL2() returned 0, causing shift exponent -1 to be negative.
This patch fixes the issue by exiting the loop directly when negative shift is found.
Reported-by: syzbot+61be3359d2ee3467e7e4@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=61be3359d2ee3467e7e4 Signed-off-by: Pei Li peili.dev@gmail.com Signed-off-by: Dave Kleikamp dave.kleikamp@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/jfs/jfs_dmap.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c index 893bc59658dad..672471f4e72c8 100644 --- a/fs/jfs/jfs_dmap.c +++ b/fs/jfs/jfs_dmap.c @@ -1707,6 +1707,8 @@ s64 dbDiscardAG(struct inode *ip, int agno, s64 minlen) } else if (rc == -ENOSPC) { /* search for next smaller log2 block */ l2nb = BLKSTOL2(nblocks) - 1; + if (unlikely(l2nb < 0)) + break; nblocks = 1LL << l2nb; } else { /* Trim any already allocated blocks */