From 4afe260bab50290a05e5732570329a530ed023f3 Mon Sep 17 00:00:00 2001 From: Federico Sauter Date: Tue, 17 Mar 2015 17:45:28 +0100 Subject: CIFS: Fix race condition on RFC1002_NEGATIVE_SESSION_RESPONSE This patch fixes a race condition that occurs when connecting to a NT 3.51 host without specifying a NetBIOS name. In that case a RFC1002_NEGATIVE_SESSION_RESPONSE is received and the SMB negotiation is reattempted, but under some conditions it leads SendReceive() to hang forever while waiting for srv_mutex. This, in turn, sets the calling process to an uninterruptible sleep state and makes it unkillable. The solution is to unlock the srv_mutex acquired in the demux thread *before* going to sleep (after the reconnect error) and before reattempting the connection. --- fs/cifs/connect.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'fs') diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c index f3bfe08e177b..8383d5ea4202 100644 --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -386,6 +386,7 @@ cifs_reconnect(struct TCP_Server_Info *server) rc = generic_ip_connect(server); if (rc) { cifs_dbg(FYI, "reconnect error %d\n", rc); + mutex_unlock(&server->srv_mutex); msleep(3000); } else { atomic_inc(&tcpSesReconnectCount); @@ -393,8 +394,8 @@ cifs_reconnect(struct TCP_Server_Info *server) if (server->tcpStatus != CifsExiting) server->tcpStatus = CifsNeedNegotiate; spin_unlock(&GlobalMid_Lock); + mutex_unlock(&server->srv_mutex); } - mutex_unlock(&server->srv_mutex); } while (server->tcpStatus == CifsNeedReconnect); return rc; -- cgit v1.2.3