Reviewed by: Alex Markuze <amarkuze@xxxxxxxxxx>
On Mon, Jun 2, 2025 at 9:50 PM Viacheslav Dubeyko <slava@xxxxxxxxxxx> wrote:
>
> From: Viacheslav Dubeyko <Slava.Dubeyko@xxxxxxx>
>
> smatch warnings:
> fs/ceph/super.c:1042 ceph_umount_begin() warn: variable dereferenced before check 'fsc' (see line 1041)
>
> vim +/fsc +1042 fs/ceph/super.c
>
> void ceph_umount_begin(struct super_block *sb)
> {
> struct ceph_fs_client *fsc = ceph_sb_to_fs_client(sb);
>
> doutc(fsc->client, "starting forced umount\n");
> ^^^^^^^^^^^
> Dereferenced
>
> if (!fsc)
> ^^^^
> Checked too late.
>
> return;
> fsc->mount_state = CEPH_MOUNT_SHUTDOWN;
> __ceph_umount_begin(fsc);
> }
>
> The VFS guarantees that the superblock is still
> alive when it calls into ceph via ->umount_begin().
> Finally, we don't need to check the fsc and
> it should be valid. This patch simply removes
> the fsc check.
>
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> Closes: https://urldefense.proofpoint.com/v2/url?u=https-3A__lore.kernel.org_r_202503280852.YDB3pxUY-2Dlkp-40intel.com_&d=DwIBAg&c=BSDicqBQBDjDI9RkVyTcHQ&r=q5bIm4AXMzc8NJu1_RGmnQ2fMWKq4Y4RAkElvUgSs00&m=Ud7uNdqBY_Z7LJ_oI4fwdhvxOYt_5Q58tpkMQgDWhV3199_TCnINFU28Esc0BaAH&s=QOKWZ9HKLyd6XCxW-AUoKiFFg9roId6LOM01202zAk0&e=
> Signed-off-by: Viacheslav Dubeyko <Slava.Dubeyko@xxxxxxx>
> ---
> fs/ceph/super.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/fs/ceph/super.c b/fs/ceph/super.c
> index f3951253e393..68a6d434093f 100644
> --- a/fs/ceph/super.c
> +++ b/fs/ceph/super.c
> @@ -1033,8 +1033,7 @@ void ceph_umount_begin(struct super_block *sb)
> struct ceph_fs_client *fsc = ceph_sb_to_fs_client(sb);
>
> doutc(fsc->client, "starting forced umount\n");
> - if (!fsc)
> - return;
> +
> fsc->mount_state = CEPH_MOUNT_SHUTDOWN;
> __ceph_umount_begin(fsc);
> }
> --
> 2.49.0
>
