linux-kernel - [PATCH] smb: client: Fix a double lock bug in smb2

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Date: Thu, 1 Feb 2024 15:18:52 +0300
From: Dan Carpenter <dan.carpenter@...aro.org>
To: Shyam Prasad N <sprasad@...rosoft.com>
Cc: Steve French <sfrench@...ba.org>, Paulo Alcantara <pc@...guebit.com>,
	Ronnie Sahlberg <ronniesahlberg@...il.com>,
	Tom Talpey <tom@...pey.com>, linux-cifs@...r.kernel.org,
	linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: [PATCH] smb: client: Fix a double lock bug in smb2_reconnect()

This goto will try to lock spin_lock(&ses->ses_lock) twice which will
lead to a deadlock.

Fixes: 17525952fa83 ("cifs: make sure that channel scaling is done only once")
Signed-off-by: Dan Carpenter <dan.carpenter@...aro.org>
---
 fs/smb/client/smb2pdu.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/smb/client/smb2pdu.c b/fs/smb/client/smb2pdu.c
index 2837fc4465a7..dcd3f6f08c7f 100644
--- a/fs/smb/client/smb2pdu.c
+++ b/fs/smb/client/smb2pdu.c
@@ -401,7 +401,7 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon,
 
 	spin_lock(&ses->ses_lock);
 	if (ses->flags & CIFS_SES_FLAG_SCALE_CHANNELS)
-		goto skip_add_channels;
+		goto skip_add_channels_locked;
 	ses->flags |= CIFS_SES_FLAG_SCALE_CHANNELS;
 	spin_unlock(&ses->ses_lock);
 
@@ -448,6 +448,7 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon,
 
 skip_add_channels:
 	spin_lock(&ses->ses_lock);
+skip_add_channels_locked:
 	ses->flags &= ~CIFS_SES_FLAG_SCALE_CHANNELS;
 	spin_unlock(&ses->ses_lock);
 
-- 
2.43.0