From nobody Fri Sep 25 02:06:41 2026 Received: from cstnet.cn (smtp25.cstnet.cn [159.226.251.25]) (using TLSv1.2 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A1DB04B7A4D; Thu, 17 Sep 2026 15:55:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=159.226.251.25 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789660532; cv=none; b=LGdYWYPfmnlWt3CpGOxeUZYhBtXBjLToro9MHx3D1DEyqr/g9KYPj3Ci3YPR4VXNIQrQoC8pUQ0rCw1WRRq+3DQ6Y1GuB1oNGLKwOyIDj8nVrE1z+niroYIRHKwT+gTFlkHHrPk+AF+j/yLNEPTRrRQh85R9hA5b2Ac9wgikCWs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789660532; c=relaxed/simple; bh=CKiDNDlAPivZUnh2+t+SQ0i9i1s0550awWQilbIllXk=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=hFf6PuOLUooFXkSiYJfOgbZOzp07GVRMbyZUJesQsgdAXF1J+FDJ95wSOQyV/fkAvXbBw3jhAx4Z9ZuhTTM64U1KXsBVkdz0jY66/qYmbF4T0Zl7UOLHfO+8HiqXKqD8eNTo8UBvu/RFinS8puDZv2+mwGcevM7iGNxsTHS1744= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=iscas.ac.cn; spf=pass smtp.mailfrom=iscas.ac.cn; arc=none smtp.client-ip=159.226.251.25 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=iscas.ac.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=iscas.ac.cn Received: from dfae2b116770.home.arpa (unknown [36.110.52.2]) by APP-05 (Coremail) with SMTP id zQCowAC36EJrDaxqhvGDCA--.6286S2; Thu, 17 Sep 2026 23:55:23 +0800 (CST) From: Wentao Liang To: alan@redhat.com Cc: danielt@kernel.org, dianders@chromium.org, gregkh@linuxfoundation.org, jason.wessel@windriver.com, jirislaby@kernel.org, kgdb-bugreport@lists.sourceforge.net, linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, Wentao Liang , stable@vger.kernel.org Subject: [PATCH] kgdboc: Fix tty driver reference leak in configure_kgdboc() Date: Thu, 17 Sep 2026 15:55:23 +0000 Message-Id: <20260917155523.2161202-1-vulab@iscas.ac.cn> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: zQCowAC36EJrDaxqhvGDCA--.6286S2 X-Coremail-Antispam: 1UD129KBjvJXoW7ZrWUCry3ZFykury5Jw48Crg_yoW8Jw4DpF 47JFy5AFn8JF48XanrXr18CFy5ua93Ka1agryUAas8Za45ZFyjkw1aqry7tr48Ar48ta47 K395Cr4UCFyqyFUanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUPSb7Iv0xC_tr1lb4IE77IF4wAFc2x0x2IEx4CE42xK8VAvwI8I cIk0rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2 AK021l84ACjcxK6xIIjxv20xvE14v26ryj6F1UM28EF7xvwVC0I7IYx2IY6xkF7I0E14v2 6F4j6r4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxV W0oVCq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv 7VC0I7IYx2IY67AKxVWUAVWUtwAv7VC2z280aVAFwI0_Cr1j6rxdMcvjeVCFs4IE7xkEbV WUJVW8JwACjcxG0xvY0x0EwIxGrwACjI8F5VAI37AI020EjII2zVCS5cI20VAGYxC7M4II rI8v6xkF7I0E8cxan2IY04v7MxkF7I0En4kS14v26r1q6r43MxAIw28IcxkI7VAKI48JMx AIw28IcVCjz48v1sIEY20_Gr43Wr1UJr1l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAq x4xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r1q6r 43MIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF 7I0E14v26r4j6F4UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxV W8Jr0_Cr1UMIIF0xvEx4A2jsIEc7CjxVAFwI0_GcCE3sUvcSsGvfC2KfnxnUUI43ZEXa7I U1oUDJUUUUU== X-CM-SenderInfo: pyxotu46lvutnvoduhdfq/1tbiBgENA2qr8889TAAAsF Content-Type: text/plain; charset="utf-8" tty_find_polling_driver() returns the tty driver with an extra reference taken by tty_driver_kref_get(). configure_kgdboc() stores it in kgdb_tty_driver but the reference is never dropped: it is leaked when kgdb_register_io_module() fails, when the configuration is cleared, and on every reconfigure. Release the reference both when unconfiguring and on the error path. Fixes: 7d7b93c1452f ("tty: kref the tty driver object") Cc: stable@vger.kernel.org Signed-off-by: Wentao Liang Reviewed-by: Douglas Anderson --- drivers/tty/serial/kgdboc.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/tty/serial/kgdboc.c b/drivers/tty/serial/kgdboc.c index 5a955c80a853..e2c8e5ec688c 100644 --- a/drivers/tty/serial/kgdboc.c +++ b/drivers/tty/serial/kgdboc.c @@ -188,6 +188,11 @@ static void cleanup_kgdboc(void) =20 kgdboc_unregister_kbd(); kgdb_unregister_io_module(&kgdboc_io_ops); + + if (kgdb_tty_driver) { + tty_driver_kref_put(kgdb_tty_driver); + kgdb_tty_driver =3D NULL; + } } =20 static int configure_kgdboc(void) @@ -254,6 +259,10 @@ static int configure_kgdboc(void) =20 noconfig: kgdboc_unregister_kbd(); + if (kgdb_tty_driver) { + tty_driver_kref_put(kgdb_tty_driver); + kgdb_tty_driver =3D NULL; + } configured =3D 0; =20 return err; --=20 2.34.1