[PATCH 5.4 15/17] can: proc: can_remove_proc(): silence remove_proc_entry warning - Greg Kroah-Hartman

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org,
	Zhang Changzhong <zhangchangzhong@huawei.com>,
	Oliver Hartkopp <socketcan@hartkopp.net>,
	Marc Kleine-Budde <mkl@pengutronix.de>
Subject: [PATCH 5.4 15/17] can: proc: can_remove_proc(): silence remove_proc_entry warning
Date: Fri, 20 Nov 2020 12:03:42 +0100	[thread overview]
Message-ID: <20201120104541.806260368@linuxfoundation.org> (raw)
In-Reply-To: <20201120104541.058449969@linuxfoundation.org>

From: Zhang Changzhong <zhangchangzhong@huawei.com>

commit 3accbfdc36130282f5ae9e6eecfdf820169fedce upstream.

If can_init_proc() fail to create /proc/net/can directory, can_remove_proc()
will trigger a warning:

WARNING: CPU: 6 PID: 7133 at fs/proc/generic.c:672 remove_proc_entry+0x17b0
Kernel panic - not syncing: panic_on_warn set ...

Fix to return early from can_remove_proc() if can proc_dir does not exists.

Signed-off-by: Zhang Changzhong <zhangchangzhong@huawei.com>
Link: https://lore.kernel.org/r/1594709090-3203-1-git-send-email-zhangchangzhong@huawei.com
Fixes: 8e8cda6d737d ("can: initial support for network namespaces")
Acked-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 net/can/proc.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/net/can/proc.c
+++ b/net/can/proc.c
@@ -471,6 +471,9 @@ void can_init_proc(struct net *net)
  */
 void can_remove_proc(struct net *net)
 {
+	if (!net->can.proc_dir)
+		return;
+
 	if (net->can.pde_version)
 		remove_proc_entry(CAN_PROC_VERSION, net->can.proc_dir);
 
@@ -498,6 +501,5 @@ void can_remove_proc(struct net *net)
 	if (net->can.pde_rcvlist_sff)
 		remove_proc_entry(CAN_PROC_RCVLIST_SFF, net->can.proc_dir);
 
-	if (net->can.proc_dir)
-		remove_proc_entry("can", net->proc_net);
+	remove_proc_entry("can", net->proc_net);
 }


