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Subject[PATCH AUTOSEL 5.4 22/26] cifs: fix missing spinlock around update to ses->status
Date
From: Steve French <stfrench@microsoft.com>

[ Upstream commit 0060a4f28a9ef45ae8163c0805e944a2b1546762 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/cifs/cifsglob.h | 3 ++-
fs/cifs/connect.c | 5 ++++-
2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index b16c994414ab..9c0e348cb00f 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -964,7 +964,7 @@ 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 */
@@ -1814,6 +1814,7 @@ require use of the stronger protocol */
* 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
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index ab9eeb5ff8e5..da0720f41ebc 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -3049,9 +3049,12 @@ void cifs_put_smb_ses(struct cifs_ses *ses)
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);

--
2.30.2
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