diff mbox series

jfs: check agwidth before calculating the control page level

Message ID tencent_F56949906EED6EC90C8027D0C6DFD2F84606@qq.com (mailing list archive)
State New, archived
Headers show
Series jfs: check agwidth before calculating the control page level | expand

Commit Message

Edward Adam Davis Dec. 3, 2024, 10:22 a.m. UTC
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@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=7c808908291a569281a9
Signed-off-by: Edward Adam Davis <eadavis@qq.com>
---
 fs/jfs/jfs_dmap.c | 5 +++++
 1 file changed, 5 insertions(+)

Comments

Dave Kleikamp Feb. 19, 2025, 9:20 p.m. UTC | #1
Catching up on long-ignored emails.

On 12/3/24 4:22AM, Edward Adam Davis via Jfs-discussion wrote:
> 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.

This value shouldn't change unless the filesystem is resized. I would 
prefer that the check was made once in dbMount().

Shaggy

> 
> Reported-and-tested-by: syzbot+7c808908291a569281a9@syzkaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=7c808908291a569281a9
> Signed-off-by: Edward Adam Davis <eadavis@qq.com>
> ---
>   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.
>   	 */
diff mbox series

Patch

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.
 	 */