Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758771AbcCVNFo (ORCPT ); Tue, 22 Mar 2016 09:05:44 -0400 Received: from lists.s-osg.org ([54.187.51.154]:55725 "EHLO lists.s-osg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752032AbcCVNFg (ORCPT ); Tue, 22 Mar 2016 09:05:36 -0400 Subject: Re: [PATCH] media: au0828 fix au0828_v4l2_close() dev_state race condition To: mchehab@osg.samsung.com, hans.verkuil@cisco.com, inki.dae@samsung.com, nenggun.kim@samsung.com, jh1009.sung@samsung.com, chehabrafael@gmail.com, tiwai@suse.com References: <1458619445-9483-1-git-send-email-shuahkh@osg.samsung.com> Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Shuah Khan From: Shuah Khan Organization: Samsung Open Source Group Message-ID: <56F1431D.3010603@osg.samsung.com> Date: Tue, 22 Mar 2016 07:05:33 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: <1458619445-9483-1-git-send-email-shuahkh@osg.samsung.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7201 Lines: 98 On 03/21/2016 10:04 PM, Shuah Khan wrote: > au0828_v4l2_close() check for dev_state == DEV_DISCONNECTED will fail to > detect the device disconnected state correctly, if au0828_v4l2_open() runs > to set the DEV_INITIALIZED bit. A loop test of bind/unbind found this bug > by increasing the likelihood of au0828_v4l2_open() occurring while unbind > is in progress. When au0828_v4l2_close() fails to detect that the device > is in disconnect state, it attempts to power down the device and fails with > the following general protection fault: > > [ 260.992962] Call Trace: > [ 260.993008] [] ? xc5000_sleep+0x8f/0xd0 [xc5000] > [ 260.993095] [] ? fe_standby+0x3c/0x50 [tuner] > [ 260.993186] [] au0828_v4l2_close+0x53c/0x620 [au0828] > [ 260.993298] [] v4l2_release+0xf0/0x210 [videodev] > [ 260.993382] [] __fput+0x1fc/0x6c0 > [ 260.993449] [] ____fput+0xe/0x10 > [ 260.993519] [] task_work_run+0x133/0x1f0 > [ 260.993602] [] exit_to_usermode_loop+0x140/0x170 > [ 260.993681] [] syscall_return_slowpath+0x16a/0x1a0 > [ 260.993754] [] entry_SYSCALL_64_fastpath+0xa6/0xa8 > > Signed-off-by: Shuah Khan Hi Mauro, Reproduced this problem on Linux 4.5. This patch should be marked for stable releases. Mar 22 06:55:16 anduin kernel: [ 883.235413] PM: Removing info for No Bus:video1 Mar 22 06:55:16 anduin kernel: [ 883.236165] device: 'vbi0': device_unregister Mar 22 06:55:16 anduin kernel: [ 883.237883] kasan: CONFIG_KASAN_INLINE enabled Mar 22 06:55:16 anduin kernel: [ 883.237893] kasan: GPF could be caused by NULL-ptr deref or user memory accessgeneral protection fault: 0000 [#1] SMP KASAN Mar 22 06:55:16 anduin kernel: [ 883.237988] Modules linked in: nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack ipt_REJECT nf_reject_ipv4 xt_tcpudp bridge stp llc ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter ip_tables x_tables snd_usb_audio snd_usbmidi_lib snd_seq_midi snd_seq_midi_event snd_seq snd_rawmidi ir_lirc_codec snd_seq_device lirc_dev binfmt_misc rc_hauppauge au8522_dig nls_iso8859_1 xc5000 tuner au8522_decoder au8522_common hp_wmi sparse_keymap au0828 ghash_clmulni_intel aesni_intel tveeprom aes_x86_64 ablk_helper dvb_core cryptd lrw gf128mul uvcvideo glue_helper rc_core v4l2_common joydev videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 videobuf2_core serio_raw videodev media k10temp i2c_piix4 snd_hda_codec_idt snd_hda_codec_generic snd_hda_codec_hdmi snd_hda_intel snd_hda_codec tpm_infineon snd_hda_core snd_hwdep snd_pcm hp_accel lis3lv02d input_polldev mac_hid snd_timer kvm_amd tpm_tis kvm irqbypass parport_pc ppdev lp parport a utofs4 p l 2303 usbserial hid_generic psmouse usbhid hid radeon i2c_algo_bit ttm drm_kms_helper syscopyarea sysfillrect sysimgblt firewire_ohci fb_sys_fops sdhci_pci firewire_core sdhci crc_itu_t r8169 drm mii wmi video Mar 22 06:55:16 anduin kernel: [ 883.239547] CPU: 1 PID: 2793 Comm: v4l_id Not tainted 4.5.0 #16 Mar 22 06:55:16 anduin kernel: [ 883.239613] Hardware name: Hewlett-Packard HP ProBook 6475b/180F, BIOS 68TTU Ver. F.04 08/03/2012 Mar 22 06:55:16 anduin kernel: [ 883.239709] task: ffff88009a0fcd80 ti: ffff8800942f0000 task.ti: ffff8800942f0000 Mar 22 06:55:16 anduin kernel: [ 883.239790] RIP: 0010:[] [] usb_set_interface+0x34/0x9d0 Mar 22 06:55:16 anduin kernel: [ 883.239896] PM: Removing info for No Bus:vbi0 Mar 22 06:55:16 anduin kernel: [ 883.239947] RSP: 0018:ffff8800942f7d10 EFLAGS: 00010212 Mar 22 06:55:16 anduin kernel: [ 883.240007] RAX: dffffc0000000000 RBX: ffff8801eef75338 RCX: ffff88009a0fd5b8 Mar 22 06:55:16 anduin kernel: [ 883.240093] RDX: 0000000000000008 RSI: 0000000000000000 RDI: 0000000000000040 Mar 22 06:55:16 anduin kernel: [ 883.240189] RBP: ffff8800942f7d88 R08: 0000000000000006 R09: 0000000000000000 Mar 22 06:55:16 anduin kernel: [ 883.240284] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801eef76874 Mar 22 06:55:16 anduin kernel: [ 883.240381] R13: 0000000000000000 R14: dffffc0000000000 R15: ffff8801eef74000 Mar 22 06:55:16 anduin kernel: [ 883.240478] FS: 00007f83985c4700(0000) GS:ffff8801fa880000(0000) knlGS:0000000000000000 Mar 22 06:55:16 anduin kernel: [ 883.240586] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b Mar 22 06:55:16 anduin kernel: [ 883.240664] CR2: 000055fd2e0ec000 CR3: 000000009426d000 CR4: 00000000000406e0 Mar 22 06:55:16 anduin kernel: [ 883.240754] Stack: Mar 22 06:55:16 anduin kernel: [ 883.240779] dffffc0000000000 ffff8801eef74000 ffff8800942f7d40 ffffffffa0f58f0f Mar 22 06:55:16 anduin kernel: [ 883.240873] ffff88009a0fd5d8 ffff8801eeee4050 ffff8800942f7d58 ffffffffa0e3803c Mar 22 06:55:16 anduin kernel: [ 883.240966] ffff880100000000 ffff880000000000 ffff8801eef75338 ffff8801eef76874 Mar 22 06:55:16 anduin kernel: [ 883.241058] Call Trace: Mar 22 06:55:16 anduin kernel: [ 883.241095] [] ? xc5000_sleep+0x8f/0xd0 [xc5000] Mar 22 06:55:16 anduin kernel: [ 883.241166] [] ? fe_standby+0x3c/0x50 [tuner] Mar 22 06:55:16 anduin kernel: [ 883.241242] [] au0828_v4l2_close+0x36e/0x570 [au0828] Mar 22 06:55:16 anduin kernel: [ 883.241348] [] v4l2_release+0xf0/0x210 [videodev] Mar 22 06:55:16 anduin kernel: [ 883.241438] [] __fput+0x1fc/0x6c0 Mar 22 06:55:16 anduin kernel: [ 883.241508] [] ____fput+0xe/0x10 Mar 22 06:55:16 anduin kernel: [ 883.241583] [] task_work_run+0x133/0x1f0 Mar 22 06:55:16 anduin kernel: [ 883.241664] [] exit_to_usermode_loop+0x140/0x170 Mar 22 06:55:16 anduin kernel: [ 883.241747] [] syscall_return_slowpath+0x156/0x1b0 Mar 22 06:55:16 anduin kernel: [ 883.241838] [] int_ret_from_sys_call+0x25/0x9f Mar 22 06:55:16 anduin kernel: [ 883.241921] Code: 00 00 00 00 fc ff df 48 89 e5 41 57 41 56 41 55 41 54 49 89 fd 53 48 83 c7 40 48 83 ec 50 89 55 c8 48 89 fa 48 c1 ea 03 89 75 d0 <80> 3c 02 00 0f 85 7b 07 00 00 49 8d 7d 18 48 b8 00 00 00 00 00 Mar 22 06:55:16 anduin kernel: [ 883.242471] RIP [] usb_set_interface+0x34/0x9d0 Mar 22 06:55:16 anduin kernel: [ 883.242612] RSP thanks, -- Shuah > --- > drivers/media/usb/au0828/au0828-video.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/media/usb/au0828/au0828-video.c b/drivers/media/usb/au0828/au0828-video.c > index 13f6dab..88dcc6e 100644 > --- a/drivers/media/usb/au0828/au0828-video.c > +++ b/drivers/media/usb/au0828/au0828-video.c > @@ -1075,7 +1075,7 @@ static int au0828_v4l2_close(struct file *filp) > del_timer_sync(&dev->vbi_timeout); > } > > - if (dev->dev_state == DEV_DISCONNECTED) > + if (dev->dev_state & DEV_DISCONNECTED) > goto end; > > if (dev->users == 1) { > -- Shuah Khan Sr. Linux Kernel Developer Open Source Innovation Group Samsung Research America (Silicon Valley) shuahkh@osg.samsung.com | (970) 217-8978