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authorRonnie Sahlberg <lsahlber@redhat.com>2018-08-30 10:12:59 +1000
committerSteve French <stfrench@microsoft.com>2018-10-02 18:12:31 -0500
commitddf83afb9f60ee58cdec30bb615eff65d00ba05e (patch)
tree41a64ddbced37ea36da1defdcd8f2eb6c0a270fa
parent0595751f267994c3c7027377058e4185b3a28e75 (diff)
downloadlinux-ddf83afb9f60ee58cdec30bb615eff65d00ba05e.tar.bz2
cifs: add a warning if we try to to dequeue a deleted mid
cifs_delete_mid() is called once we are finished handling a mid and we expect no more work done on this mid. Needed to fix recent commit: commit 730928c8f4be88e9d6a027a16b1e8fa9c59fc077 ("cifs: update smb2_queryfs() to use compounding") 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> Signed-off-by: Steve French <stfrench@microsoft.com> Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
-rw-r--r--fs/cifs/cifsglob.h1
-rw-r--r--fs/cifs/connect.c10
-rw-r--r--fs/cifs/transport.c3
3 files changed, 12 insertions, 2 deletions
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 0c9ab62c3df4..9dcaed031843 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -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 */
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 7aa08dba4719..e9d64c92b8da 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -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);
}
diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index 78f96fa3d7d9..9cc9a127749e 100644
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -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);