2023-02-07 17:07 GMT+09:00, Hangyu Hua <hbh25y@xxxxxxxxx>:
> argv needs to be free when setup_async_work fails or when the current
> process is woken up.
>
> Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3")
> Signed-off-by: Hangyu Hua <hbh25y@xxxxxxxxx>
> ---
>
> v2: avoid NULL pointer dereference in set_close_state_blocked_works()
> v3: avoid race condition between smb2_lock() and smb2_cancel()
>
> fs/ksmbd/smb2pdu.c | 23 ++++++++++++++---------
> fs/ksmbd/vfs_cache.c | 2 ++
> 2 files changed, 16 insertions(+), 9 deletions(-)
>
> diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c
> index d681f91947d9..f4079518eaf6 100644
> --- a/fs/ksmbd/smb2pdu.c
> +++ b/fs/ksmbd/smb2pdu.c
> @@ -6644,7 +6644,7 @@ int smb2_cancel(struct ksmbd_work *work)
> struct ksmbd_conn *conn = work->conn;
> struct smb2_hdr *hdr = smb2_get_msg(work->request_buf);
> struct smb2_hdr *chdr;
> - struct ksmbd_work *cancel_work = NULL, *iter;
> + struct ksmbd_work *iter;
> struct list_head *command_list;
>
> ksmbd_debug(SMB, "smb2 cancel called on mid %llu, async flags 0x%x\n",
> @@ -6666,7 +6666,9 @@ int smb2_cancel(struct ksmbd_work *work)
> "smb2 with AsyncId %llu cancelled command = 0x%x\n",
> le64_to_cpu(hdr->Id.AsyncId),
> le16_to_cpu(chdr->Command));
> - cancel_work = iter;
> + iter->state = KSMBD_WORK_CANCELLED;
> + if (iter->cancel_fn)
> + iter->cancel_fn(iter->cancel_argv);
> break;
> }
> spin_unlock(&conn->request_lock);
> @@ -6685,18 +6687,12 @@ int smb2_cancel(struct ksmbd_work *work)
> "smb2 with mid %llu cancelled command = 0x%x\n",
> le64_to_cpu(hdr->MessageId),
> le16_to_cpu(chdr->Command));
> - cancel_work = iter;
> + iter->state = KSMBD_WORK_CANCELLED;
> break;
> }
> spin_unlock(&conn->request_lock);
> }
>
> - if (cancel_work) {
> - cancel_work->state = KSMBD_WORK_CANCELLED;
> - if (cancel_work->cancel_fn)
> - cancel_work->cancel_fn(cancel_work->cancel_argv);
> - }
> -
> /* For SMB2_CANCEL command itself send no response*/
> work->send_no_response = 1;
> return 0;
> @@ -7050,6 +7046,7 @@ int smb2_lock(struct ksmbd_work *work)
> smb2_remove_blocked_lock,
> argv);
> if (rc) {
> + kfree(argv);
> err = -ENOMEM;
> goto out;
> }
> @@ -7061,6 +7058,10 @@ int smb2_lock(struct ksmbd_work *work)
>
> ksmbd_vfs_posix_lock_wait(flock);
>
> + spin_lock(&work->conn->request_lock);
> + list_del_init(&work->async_request_entry);
It is called again in ksmbd_conn_try_dequeue_request().
> + spin_unlock(&work->conn->request_lock);
> +
