[PATCH AUTOSEL 6.2 18/18] cifs: missing lock when updating session status

Sasha Levin
2023-05-09T21:22:31Z

From: Steve French <stfrench@microsoft.com>

[ Upstream commit 943fb67b090212f1d3789eb7796b1c9045c62fd6 ]

Coverity noted a place where we were not grabbing
the ses_lock when setting (and checking) ses_status.

Addresses-Coverity: 1536833 ("Data race condition (MISSING_LOCK)")
Reviewed-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Reviewed-by: Bharath SM <bharathsm@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/cifs/connect.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 985e962cf0858..860e533ad1bf0 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -1965,18 +1965,22 @@ void cifs_put_smb_ses(struct cifs_ses *ses)
/* ses_count can never go negative */
WARN_ON(ses->ses_count < 0);

+ spin_lock(&ses->ses_lock);
if (ses->ses_status == SES_GOOD)
ses->ses_status = SES_EXITING;

- cifs_free_ipc(ses);
-
if (ses->ses_status == SES_EXITING && server->ops->logoff) {
+ spin_unlock(&ses->ses_lock);
+ cifs_free_ipc(ses);
xid = get_xid();
rc = server->ops->logoff(xid, ses);
if (rc)
cifs_server_dbg(VFS, "%s: Session Logoff failure rc=%d\n",
__func__, rc);
_free_xid(xid);
+ } else {
+ spin_unlock(&ses->ses_lock);
+ cifs_free_ipc(ses);
}

spin_lock(&cifs_tcp_ses_lock);
--
2.39.2