From: Steve French <stfrench@microsoft.com>
Date: Thu, 24 Jun 2021 15:28:04 -0500
Subject: [PATCH] cifs: fix missing spinlock around update to ses->status
Git-commit: 0060a4f28a9ef45ae8163c0805e944a2b1546762
References: bsc#1190317
Patch-mainline: v5.13

In the other places where we update ses->status we protect the
updates via GlobalMid_Lock. So to be consistent add the same
locking around it in cifs_put_smb_ses where it was missing.

Addresses-Coverity: 1268904 ("Data race condition")
Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Enzo Matsumiya <ematsumiya@suse.de>
---
 fs/cifs/cifsglob.h | 3 ++-
 fs/cifs/connect.c  | 5 ++++-
 2 files changed, 6 insertions(+), 2 deletions(-)

--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -975,7 +975,7 @@ struct cifs_ses {
 	struct mutex session_mutex;
 	struct TCP_Server_Info *server;	/* pointer to server info */
 	int ses_count;		/* reference counter */
-	enum statusEnum status;
+	enum statusEnum status;  /* updates protected by GlobalMid_Lock */
 	unsigned overrideSecFlg;  /* if non-zero override global sec flags */
 	char *serverOS;		/* name of operating system underlying server */
 	char *serverNOS;	/* name of network operating system of server */
@@ -1817,6 +1817,8 @@ require use of the stronger protocol */
  *  GlobalMid_Lock protects:
  *	list operations on pending_mid_q and oplockQ
  *      updates to XID counters, multiplex id  and SMB sequence numbers
+ *      list operations on global DnotifyReqList
+ *      updates to ses->status
  *  tcp_ses_lock protects:
  *	list operations on tcp and SMB session lists
  *  tcon->open_file_lock protects the list of open files hanging off the tcon
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -2977,9 +2977,12 @@ void cifs_put_smb_ses(struct cifs_ses *s
 		spin_unlock(&cifs_tcp_ses_lock);
 		return;
 	}
+	spin_unlock(&cifs_tcp_ses_lock);
+
+	spin_lock(&GlobalMid_Lock);
 	if (ses->status == CifsGood)
 		ses->status = CifsExiting;
-	spin_unlock(&cifs_tcp_ses_lock);
+	spin_unlock(&GlobalMid_Lock);
 
 	cifs_free_ipc(ses);