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From:   Du Cheng <ducheng2@gmail.com>
To:     Johannes Berg <johannes@sipsolutions.net>
Cc:     linux-wireless@vger.kernel.org,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Shuah Khan <skhan@linuxfoundation.org>,
        Du Cheng <ducheng2@gmail.com>,
        syzbot+5f9392825de654244975@syzkaller.appspotmail.com
Subject: [PATCH] net: wireless: convert WARN_ON() to pr_warn() in cfg80211_sme_connect
Date:   Wed,  7 Apr 2021 10:19:03 +0800
Message-Id: <20210407021903.384158-1-ducheng2@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

A WARN_ON(wdev->conn) would trigger in cfg80211_sme_connect(), if
multiple send_msg() system calls are made from the userland, which
should be anticipated and handled by the wireless driver. Convert this
WARN() to pr_warn to prevent a kernel panic if kernel is configured to
"panic on warn".

Bug reported by syzbot.

Reported-by: syzbot+5f9392825de654244975@syzkaller.appspotmail.com
Signed-off-by: Du Cheng <ducheng2@gmail.com>
---
link to syzkaller:
https://syzkaller.appspot.com/bug?extid=5f9392825de654244975
this patch has passed syzbot test.
 net/wireless/sme.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/wireless/sme.c b/net/wireless/sme.c
index 07756ca5e3b5..87a65a4c40ae 100644
--- a/net/wireless/sme.c
+++ b/net/wireless/sme.c
@@ -529,8 +529,10 @@ static int cfg80211_sme_connect(struct wireless_dev *wdev,
 		cfg80211_sme_free(wdev);
 	}
 
-	if (WARN_ON(wdev->conn))
+	if (wdev->conn) {
+		pr_warn("%s: wdev->conn != NULL, sme connect in progress", __func__);
 		return -EINPROGRESS;
+	}
 
 	wdev->conn = kzalloc(sizeof(*wdev->conn), GFP_KERNEL);
 	if (!wdev->conn)
-- 
2.30.2