@@ -1553,6 +1553,7 @@ static inline void free_dfs_info_array(struct dfs_info3_param *param,
/* Flags */
#define MID_WAIT_CANCELLED 1 /* Cancelled while waiting for response */
+#define MID_DELETED 2 /* Mid has been dequeued/deleted */
/* Types of response buffer returned from SendReceive2 */
#define CIFS_NO_BUFFER 0 /* Response buffer not returned */
@@ -659,7 +659,15 @@ dequeue_mid(struct mid_q_entry *mid, bool malformed)
mid->mid_state = MID_RESPONSE_RECEIVED;
else
mid->mid_state = MID_RESPONSE_MALFORMED;
- list_del_init(&mid->qhead);
+ /*
+ * Trying to handle/dequeue a mid after the send_recv()
+ * function has finished processing it is a bug.
+ */
+ if (mid->mid_flags & MID_DELETED)
+ printk_once(KERN_WARNING
+ "trying to dequeue a deleted mid\n");
+ else
+ list_del_init(&mid->qhead);
spin_unlock(&GlobalMid_Lock);
}
@@ -142,7 +142,8 @@ void
cifs_delete_mid(struct mid_q_entry *mid)
{
spin_lock(&GlobalMid_Lock);
- list_del(&mid->qhead);
+ list_del_init(&mid->qhead);
+ mid->mid_flags |= MID_DELETED;
spin_unlock(&GlobalMid_Lock);
DeleteMidQEntry(mid);
cifs_delete_mid() is called once we are finished handling a mid and we expect no more work done on this mid. Add a warning if someone tries to dequeue a mid that has already been flagged to be deleted. Also change list_del() to list_del_init() so that if we have similar bugs resurface in the future we will not oops. Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com> --- fs/cifs/cifsglob.h | 1 + fs/cifs/connect.c | 10 +++++++++- fs/cifs/transport.c | 3 ++- 3 files changed, 12 insertions(+), 2 deletions(-)