From patchwork Mon Oct 30 10:07:29 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthias Schwarzott X-Patchwork-Id: 10032273 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 67203600C5 for ; Mon, 30 Oct 2017 10:07:20 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4F34728815 for ; Mon, 30 Oct 2017 10:07:20 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4274128816; Mon, 30 Oct 2017 10:07:20 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C559F24B44 for ; Mon, 30 Oct 2017 10:07:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752504AbdJ3KHS (ORCPT ); Mon, 30 Oct 2017 06:07:18 -0400 Received: from smtp.gentoo.org ([140.211.166.183]:39660 "EHLO smtp.gentoo.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752501AbdJ3KHR (ORCPT ); Mon, 30 Oct 2017 06:07:17 -0400 Received: from gauss.fritz.box (unknown [IPv6:2001:a62:2df:e901:956d:8aad:a2a0:d521]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: zzam) by smtp.gentoo.org (Postfix) with ESMTPSA id 2DC29341683; Mon, 30 Oct 2017 10:07:16 +0000 (UTC) From: Matthias Schwarzott To: mchehab@kernel.org, linux-media@vger.kernel.org Cc: Matthias Schwarzott Subject: [PATCH] em28xx: Fix use-after-free when disconnecting Date: Mon, 30 Oct 2017 11:07:29 +0100 Message-Id: <20171030100729.6430-1-zzam@gentoo.org> X-Mailer: git-send-email 2.14.2 Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Fix bug by moving the i2c_unregister_device calls after deregistration of dvb frontend. The new style i2c drivers already destroys the frontend object at i2c_unregister_device time. When the dvb frontend is unregistered afterwards it leads to this oops: [ 6058.866459] BUG: unable to handle kernel NULL pointer dereference at 00000000000001f8 [ 6058.866578] IP: dvb_frontend_stop+0x30/0xd0 [dvb_core] [ 6058.866644] PGD 0 [ 6058.866646] P4D 0 [ 6058.866726] Oops: 0000 [#1] SMP [ 6058.866768] Modules linked in: rc_pinnacle_pctv_hd(O) em28xx_rc(O) si2157(O) si2168(O) em28xx_dvb(O) em28xx(O) si2165(O) a8293(O) tda10071(O) tea5767(O) tuner(O) cx23885(O) tda18271(O) videobuf2_dvb(O) videobuf2_dma_sg(O) m88ds3103(O) tveeprom(O) cx2341x(O) v4l2_common(O) dvb_core(O) rc_core(O) videobuf2_memops(O) videobuf2_v4l2(O) videobuf2_core(O) videodev(O) media(O) bluetooth ecdh_generic ums_realtek uas rtl8192cu rtl_usb rtl8192c_common rtlwifi usb_storage snd_hda_codec_realtek snd_hda_codec_hdmi snd_hda_codec_generic i2c_mux snd_hda_intel snd_hda_codec snd_hwdep x86_pkg_temp_thermal snd_hda_core kvm_intel kvm irqbypass [last unloaded: videobuf2_memops] [ 6058.867497] CPU: 2 PID: 7349 Comm: kworker/2:0 Tainted: G W O 4.13.9-gentoo #1 [ 6058.867595] Hardware name: MEDION E2050 2391/H81H3-EM2, BIOS H81EM2W08.308 08/25/2014 [ 6058.867692] Workqueue: usb_hub_wq hub_event [ 6058.867746] task: ffff88011a15e040 task.stack: ffffc90003074000 [ 6058.867825] RIP: 0010:dvb_frontend_stop+0x30/0xd0 [dvb_core] [ 6058.867896] RSP: 0018:ffffc90003077b58 EFLAGS: 00010293 [ 6058.867964] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 000000010040001f [ 6058.868056] RDX: ffff88011a15e040 RSI: ffffea000464e400 RDI: ffff88001cbe3028 [ 6058.868150] RBP: ffffc90003077b68 R08: ffff880119390380 R09: 000000010040001f [ 6058.868241] R10: ffffc90003077b18 R11: 000000000001e200 R12: ffff88001cbe3028 [ 6058.868330] R13: ffff88001cbe68d0 R14: ffff8800cf734000 R15: ffff8800cf734098 [ 6058.868419] FS: 0000000000000000(0000) GS:ffff88011fb00000(0000) knlGS:0000000000000000 [ 6058.868511] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 6058.868578] CR2: 00000000000001f8 CR3: 00000001113c5000 CR4: 00000000001406e0 [ 6058.868662] Call Trace: [ 6058.868705] dvb_unregister_frontend+0x2a/0x80 [dvb_core] [ 6058.868774] em28xx_dvb_fini+0x132/0x220 [em28xx_dvb] [ 6058.868840] em28xx_close_extension+0x34/0x90 [em28xx] [ 6058.868902] em28xx_usb_disconnect+0x4e/0x70 [em28xx] [ 6058.868968] usb_unbind_interface+0x6d/0x260 [ 6058.869025] device_release_driver_internal+0x150/0x210 [ 6058.869094] device_release_driver+0xd/0x10 [ 6058.869150] bus_remove_device+0xe4/0x160 [ 6058.869204] device_del+0x1ce/0x2f0 [ 6058.869253] usb_disable_device+0x99/0x270 [ 6058.869306] usb_disconnect+0x8d/0x260 [ 6058.869359] hub_event+0x93d/0x1520 [ 6058.869408] ? dequeue_task_fair+0xae5/0xd20 [ 6058.869467] process_one_work+0x1d9/0x3e0 [ 6058.869522] worker_thread+0x43/0x3e0 [ 6058.869576] kthread+0x104/0x140 [ 6058.869602] ? trace_event_raw_event_workqueue_work+0x80/0x80 [ 6058.869640] ? kthread_create_on_node+0x40/0x40 [ 6058.869673] ret_from_fork+0x22/0x30 [ 6058.869698] Code: 54 49 89 fc 53 48 8b 9f 18 03 00 00 0f 1f 44 00 00 41 83 bc 24 04 05 00 00 02 74 0c 41 c7 84 24 04 05 00 00 01 00 00 00 0f ae f0 <48> 8b bb f8 01 00 00 48 85 ff 74 5c e8 df 40 f0 e0 48 8b 93 f8 [ 6058.869850] RIP: dvb_frontend_stop+0x30/0xd0 [dvb_core] RSP: ffffc90003077b58 [ 6058.869894] CR2: 00000000000001f8 [ 6058.875880] ---[ end trace 717eecf7193b3fc6 ]--- Signed-off-by: Matthias Schwarzott --- drivers/media/usb/em28xx/em28xx-dvb.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/media/usb/em28xx/em28xx-dvb.c b/drivers/media/usb/em28xx/em28xx-dvb.c index 4a7db623fe29..29cdaaf1ed90 100644 --- a/drivers/media/usb/em28xx/em28xx-dvb.c +++ b/drivers/media/usb/em28xx/em28xx-dvb.c @@ -2105,6 +2105,8 @@ static int em28xx_dvb_fini(struct em28xx *dev) } } + em28xx_unregister_dvb(dvb); + /* remove I2C SEC */ client = dvb->i2c_client_sec; if (client) { @@ -2126,7 +2128,6 @@ static int em28xx_dvb_fini(struct em28xx *dev) i2c_unregister_device(client); } - em28xx_unregister_dvb(dvb); kfree(dvb); dev->dvb = NULL; kref_put(&dev->ref, em28xx_free_device);