The width in dmapctl of the AG is zero, it trigger a divide error when calculating the control page level in dbAllocAG. To avoid this issue, add a check for agwidth in dbAllocAG. Reported-and-tested-by: syzbot+7c808908291a569281a9@xxxxxxxxxxxxxxxxxxxxxxxxx Closes: https://syzkaller.appspot.com/bug?extid=7c808908291a569281a9 Signed-off-by: Edward Adam Davis <eadavis@xxxxxx> --- fs/jfs/jfs_dmap.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c index f9009e4f9ffd..2377102d9c4c 100644 --- a/fs/jfs/jfs_dmap.c +++ b/fs/jfs/jfs_dmap.c @@ -1373,6 +1373,11 @@ dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb, s64 * results) return (rc); } + if (!bmp->db_agwidth) { + jfs_error(bmp->db_ipbmap->i_sb, "width in dmapctl of the AG is zero\n"); + return -EIO; + } + /* the buffer for the dmap control page that fully describes the * allocation group. */ -- 2.47.0
