From nobody Fri Jun 19 00:56:16 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C9FA1C433F5 for ; Sun, 10 Apr 2022 11:55:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238595AbiDJLuh (ORCPT ); Sun, 10 Apr 2022 07:50:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42310 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230057AbiDJLuf (ORCPT ); Sun, 10 Apr 2022 07:50:35 -0400 Received: from mail-pj1-x102f.google.com (mail-pj1-x102f.google.com [IPv6:2607:f8b0:4864:20::102f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9D93A2E6A7 for ; Sun, 10 Apr 2022 04:48:25 -0700 (PDT) Received: by mail-pj1-x102f.google.com with SMTP id md20-20020a17090b23d400b001cb70ef790dso2061508pjb.5 for ; Sun, 10 Apr 2022 04:48:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=+Wa9XPtQomZw9/qSdanoMdYPd0EpQEW8XKYDlUj1N1w=; b=O/u0lYLdcpcBNSW+V5qHCpVsK0bkoX0+2w7PwPl0iwR+07qiSOkjoL9BCtT7LPIR7k lCQpcZc6HaYgAaD/PDoHWkalH+1h3BMaNI1dSkQt8QAzy4hETCfgN+ixb6T1Qqrs3pLy mR6c5cp1eUeCMmyY0JxQyMZpZlHCmkyVSArKkiMF7F745retyg1CpzOax7U4SR01XQt8 bk0gSUKnhD94Sj3w7mZ4PpwPJgf4/UUoSZp+Y8ttGWXq/SG3cp82vC9msTmU6sTi9mz9 Z5P/zPHQP/T0D8jTsE/yISA3mvEjdg2Mhs/Zd8oVCQVvFRQtdE437C5Ae++9fpvJ1u/a +Qyg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=+Wa9XPtQomZw9/qSdanoMdYPd0EpQEW8XKYDlUj1N1w=; b=NOJNbKf8OOetkP6kY3oQ+Tt9FwaecXGKzGYQrE2PgYhSNWdeErSzc6BgdmIIt4oLRh dJZ33v2aVsfsHTnTeGnAFwoewxFbrNHcbDzMCDNIccA2yzBFA73r7RqAGRWdMYttAkOZ gpernjwwDMP+LW92KiMzj44XJaaBm8cvtg1nJwbRUjjyMXs6Cfq7lLgH3z2p9e7Vlrur ocOE4k2BbKRgOAW56WLHUXDrkH+m4VyVROGNJJAF6UYz1f55MCj82geVEY2mW10+ncsD mGWoF3joB0wKwtUxi+tCp9WNcHeew7Cr7dVXHNLpQuDdGJP7OSR1Y826h1k+xwfQK+Ga O4/A== X-Gm-Message-State: AOAM5336Cl+KY4bXxdLWBH63S3heTNqD5d2o3x8PPbTjtTeV1EkfKK5/ 7lL891p1pVMmz2vmSXKmrQ== X-Google-Smtp-Source: ABdhPJzg3V1MNZAFs4oTOJwzWdkxsaLklLwaK/R2HsgboUKWbtiManpRTf1wLVJjTrQTImu6rF9igQ== X-Received: by 2002:a17:90b:4c0f:b0:1c7:d2de:5aec with SMTP id na15-20020a17090b4c0f00b001c7d2de5aecmr31515353pjb.110.1649591305160; Sun, 10 Apr 2022 04:48:25 -0700 (PDT) Received: from localhost.localdomain ([144.202.91.207]) by smtp.gmail.com with ESMTPSA id t31-20020a056a00139f00b00505b8a8ac08sm1307119pfg.160.2022.04.10.04.48.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 10 Apr 2022 04:48:24 -0700 (PDT) From: Zheyu Ma To: gregkh@linuxfoundation.org, jirislaby@kernel.org Cc: linux-kernel@vger.kernel.org, Zheyu Ma Subject: [PATCH] tty: synclink_gt: Fix null-pointer-dereference in slgt_clean() Date: Sun, 10 Apr 2022 19:48:14 +0800 Message-Id: <20220410114814.3920474-1-zheyuma97@gmail.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" When the driver fails at alloc_hdlcdev(), and then we remove the driver module, we will get the following splat: [ 25.065966] general protection fault, probably for non-canonical address= 0xdffffc0000000182: 0000 [#1] PREEMPT SMP KASAN PTI [ 25.066914] KASAN: null-ptr-deref in range [0x0000000000000c10-0x0000000= 000000c17] [ 25.069262] RIP: 0010:detach_hdlc_protocol+0x2a/0x3e0 [ 25.077709] Call Trace: [ 25.077924] [ 25.078108] unregister_hdlc_device+0x16/0x30 [ 25.078481] slgt_cleanup+0x157/0x9f0 [synclink_gt] Fix this by checking whether the 'info->netdev' is a null pointer first. Signed-off-by: Zheyu Ma Reviewed-by: Jiri Slaby --- drivers/tty/synclink_gt.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/tty/synclink_gt.c b/drivers/tty/synclink_gt.c index 25c558e65ece..9bc2a9265277 100644 --- a/drivers/tty/synclink_gt.c +++ b/drivers/tty/synclink_gt.c @@ -1746,6 +1746,8 @@ static int hdlcdev_init(struct slgt_info *info) */ static void hdlcdev_exit(struct slgt_info *info) { + if (!info->netdev) + return; unregister_hdlc_device(info->netdev); free_netdev(info->netdev); info->netdev =3D NULL; --=20 2.25.1