On Tue, Jul 10, 2012 at 1:58 PM, Sachin Prabhu <sprabhu@xxxxxxxxxx> wrote: > A user reported a crash in cifs_demultiplex_thread() caused by an > incorrectly set mid_q_entry->callback() function. It appears that the > callback assignment made in cifs_call_async() was not flushed back to > memory suggesting that a memory barrier was required here. Changing the > code to make sure that the mid_q_entry structure was completely > initialised before it was added to the pending queue fixes the problem. > > Signed-off-by: Sachin Prabhu <sprabhu@xxxxxxxxxx> > --- > fs/cifs/transport.c | 20 ++++++++++---------- > 1 file changed, 10 insertions(+), 10 deletions(-) > > diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c > index 3097ee5..c5faf02 100644 > --- a/fs/cifs/transport.c > +++ b/fs/cifs/transport.c > @@ -365,14 +365,10 @@ cifs_setup_async_request(struct TCP_Server_Info *server, struct kvec *iov, > if (mid == NULL) > return -ENOMEM; > > - /* put it on the pending_mid_q */ > - spin_lock(&GlobalMid_Lock); > - list_add_tail(&mid->qhead, &server->pending_mid_q); > - spin_unlock(&GlobalMid_Lock); > - > rc = cifs_sign_smb2(iov, nvec, server, &mid->sequence_number); > if (rc) > - delete_mid(mid); > + DeleteMidQEntry(mid); > + > *ret_mid = mid; Looks correct. But just a thought, why bother assigning ret_mid a Deleted mid if rc is not null? > return rc; > } > @@ -407,17 +403,21 @@ cifs_call_async(struct TCP_Server_Info *server, struct kvec *iov, > mid->callback_data = cbdata; > mid->mid_state = MID_REQUEST_SUBMITTED; > > + /* put it on the pending_mid_q */ > + spin_lock(&GlobalMid_Lock); > + list_add_tail(&mid->qhead, &server->pending_mid_q); > + spin_unlock(&GlobalMid_Lock); > + > + > cifs_in_send_inc(server); > rc = smb_sendv(server, iov, nvec); > cifs_in_send_dec(server); > cifs_save_when_sent(mid); > mutex_unlock(&server->srv_mutex); > > - if (rc) > - goto out_err; > + if (rc == 0) > + return 0; > > - return rc; > -out_err: > delete_mid(mid); > add_credits(server, 1); > wake_up(&server->request_q); > -- > 1.7.10.4 > -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
