From: Shyam Prasad N <sprasad@microsoft.com>

Date: Wed, 6 Jul 2022 14:29:12 +0000

Subject: [PATCH] cifs: remove unnecessary locking of chan_lock while freeing

 session

Git-commit: 2883f4b5a0e1ac9472c7e3ae9bbdb4ea5a2117c6

References: bsc#1193629

Patch-mainline: v5.19-rc7

In cifs_put_smb_ses, when we're freeing the last ref count to

the session, we need to free up each channel. At this point,

it is unnecessary to take chan_lock, since we have the last

reference to the ses.

Picking up this lock also introduced a deadlock because it calls

cifs_put_tcp_ses, which locks cifs_tcp_ses_lock.

Signed-off-by: Shyam Prasad N <sprasad@microsoft.com>

Acked-by: Enzo Matsumiya <ematsumiya@suse.de>

Signed-off-by: Steve French <stfrench@microsoft.com>

Acked-by: Paulo Alcantara <palcantara@suse.de>

---

 fs/cifs/connect.c | 2 --

 1 file changed, 2 deletions(-)

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c

index fa29c9aae24b..386bb523c69e 100644

--- a/fs/cifs/connect.c

+++ b/fs/cifs/connect.c

@@ -1918,7 +1918,6 @@ void cifs_put_smb_ses(struct cifs_ses *ses)

 	list_del_init(&ses->smb_ses_list);

 	spin_unlock(&cifs_tcp_ses_lock);

-	spin_lock(&ses->chan_lock);

 	chan_count = ses->chan_count;

 	/* close any extra channels */

@@ -1934,7 +1933,6 @@ void cifs_put_smb_ses(struct cifs_ses *ses)

 			ses->chans[i].server = NULL;

 		}

 	}

-	spin_unlock(&ses->chan_lock);

 	sesInfoFree(ses);

 	cifs_put_tcp_session(server, 0);

-- 

2.37.3