From mboxrd@z Thu Jan 1 00:00:00 1970 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 43F39CCA482 for ; Tue, 7 Jun 2022 19:53:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1357695AbiFGTul (ORCPT ); Tue, 7 Jun 2022 15:50:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57842 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1354517AbiFGSrG (ORCPT ); Tue, 7 Jun 2022 14:47:06 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 51DA17B9E8; Tue, 7 Jun 2022 11:01:41 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 03529B82354; Tue, 7 Jun 2022 18:01:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id ED9E6C34115; Tue, 7 Jun 2022 18:01:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1654624898; bh=cO+MlwZPZfzLK6MD1rKEn5/lcgTLQLFpZ1PoZlE/mYg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=U1Gxm2BsDSPu3bPIQwYieDTQd8Lv/I4UzPEL+jAAKsue1KrNTHSPkSpaIgiFRW7b4 DShmjT/NQtcOkDHX38TTEPFAkMOlpZbfGMrv4AExrffL24blSCaVtdUEpCyvFP6Fod Tqeq3aW/KENTtnM1540TjO3kXwd09VcjjNYH1NaNx9BZDWFHzvhcQ451SgNoPapdMn GStYVb4kV3FjBxaYzCAYzv+LynctDVz0P/vJZ1Cjv3i4qDUlBVlej+9swYazbAoQEw GnTMYBrbGoZ2IF1axFKrSlDk6MYNv26DSxPEVnu1jva36uF/N9A2nV6wcbdmgubDWj tx94J9UZtZPXg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Zheyu Ma , Jiri Slaby , Greg Kroah-Hartman , Sasha Levin Subject: [PATCH AUTOSEL 4.19 03/27] tty: synclink_gt: Fix null-pointer-dereference in slgt_clean() Date: Tue, 7 Jun 2022 14:01:07 -0400 Message-Id: <20220607180133.481701-3-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220607180133.481701-1-sashal@kernel.org> References: <20220607180133.481701-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Zheyu Ma [ Upstream commit 689ca31c542687709ba21ec2195c1fbce34fd029 ] 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 [0x0000000000000c10-0x0000000000000c17] [ 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. Reviewed-by: Jiri Slaby Signed-off-by: Zheyu Ma Link: https://lore.kernel.org/r/20220410114814.3920474-1-zheyuma97@gmail.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- 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 afe34beec720..11c62fcd67f2 100644 --- a/drivers/tty/synclink_gt.c +++ b/drivers/tty/synclink_gt.c @@ -1753,6 +1753,8 @@ 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 = NULL; -- 2.35.1