From: Pavel Shilovsky Date: Thu, 21 Nov 2019 19:35:14 +0000 (-0800) Subject: CIFS: Do not miss cancelled OPEN responses X-Git-Tag: v5.5-rc1~117^2~23 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=7b71843fa7028475b052107664cbe120156a2cfc;p=linux.git CIFS: Do not miss cancelled OPEN responses When an OPEN command is cancelled we mark a mid as cancelled and let the demultiplex thread process it by closing an open handle. The problem is there is a race between a system call thread and the demultiplex thread and there may be a situation when the mid has been already processed before it is set as cancelled. Fix this by processing cancelled requests when mids are being destroyed which means that there is only one thread referencing a particular mid. Also set mids as cancelled unconditionally on their state. Cc: Stable Tested-by: Frank Sorenson Reviewed-by: Ronnie Sahlberg Signed-off-by: Pavel Shilovsky Signed-off-by: Steve French --- diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c index 40b2a173ba0d..a7a026795bc2 100644 --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -1237,12 +1237,6 @@ cifs_demultiplex_thread(void *p) for (i = 0; i < num_mids; i++) { if (mids[i] != NULL) { mids[i]->resp_buf_size = server->pdu_size; - if ((mids[i]->mid_flags & MID_WAIT_CANCELLED) && - mids[i]->mid_state == MID_RESPONSE_RECEIVED && - server->ops->handle_cancelled_mid) - server->ops->handle_cancelled_mid( - mids[i]->resp_buf, - server); if (!mids[i]->multiRsp || mids[i]->multiEnd) mids[i]->callback(mids[i]); diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c index f27842fb9f75..19300e0cf1d6 100644 --- a/fs/cifs/transport.c +++ b/fs/cifs/transport.c @@ -93,8 +93,14 @@ static void _cifs_mid_q_entry_release(struct kref *refcount) __u16 smb_cmd = le16_to_cpu(midEntry->command); unsigned long now; unsigned long roundtrip_time; - struct TCP_Server_Info *server = midEntry->server; #endif + struct TCP_Server_Info *server = midEntry->server; + + if (midEntry->resp_buf && (midEntry->mid_flags & MID_WAIT_CANCELLED) && + midEntry->mid_state == MID_RESPONSE_RECEIVED && + server->ops->handle_cancelled_mid) + server->ops->handle_cancelled_mid(midEntry->resp_buf, server); + midEntry->mid_state = MID_FREE; atomic_dec(&midCount); if (midEntry->large_buf) @@ -1119,8 +1125,8 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses, midQ[i]->mid, le16_to_cpu(midQ[i]->command)); send_cancel(server, &rqst[i], midQ[i]); spin_lock(&GlobalMid_Lock); + midQ[i]->mid_flags |= MID_WAIT_CANCELLED; if (midQ[i]->mid_state == MID_REQUEST_SUBMITTED) { - midQ[i]->mid_flags |= MID_WAIT_CANCELLED; midQ[i]->callback = cifs_cancelled_callback; cancelled_mid[i] = true; credits[i].value = 0;