From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from smtp2-g21.free.fr ([212.27.42.2]:53796 "EHLO smtp2-g21.free.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754083Ab0C0WEt (ORCPT ); Sat, 27 Mar 2010 18:04:49 -0400 Received: from smtp2-g21.free.fr (localhost [127.0.0.1]) by smtp2-g21.free.fr (Postfix) with ESMTP id 1EA114B0045 for ; Sat, 27 Mar 2010 23:04:43 +0100 (CET) Received: from [192.168.1.234] (cac94-1-81-57-151-96.fbx.proxad.net [81.57.151.96]) by smtp2-g21.free.fr (Postfix) with ESMTP id 209844B00D9 for ; Sat, 27 Mar 2010 23:04:41 +0100 (CET) Message-ID: <4BAE810A.6030405@free.fr> Date: Sat, 27 Mar 2010 23:04:58 +0100 From: matthieu castet MIME-Version: 1.0 To: linux-media@vger.kernel.org Subject: [PATCH] fix dvb frontend lockup References: <4BA603AB.6070809@free.fr> In-Reply-To: <4BA603AB.6070809@free.fr> Content-Type: multipart/mixed; boundary="------------060505080405020005080704" Sender: linux-media-owner@vger.kernel.org List-ID: This is a multi-part message in MIME format. --------------060505080405020005080704 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit matthieu castet a écrit : > Hi, > > With my current kernel (2.6.32), if my dvb device is removed while in > use, I got [1]. > > After checking the source code, the problem seems to happen also in > master : > > If there are users (for example users == -2) : > - dvb_unregister_frontend : > - stop kernel thread with dvb_frontend_stop : > - fepriv->exit = 1; > - thread loop catch stop event and break while loop > - fepriv->thread = NULL; and fepriv->exit = 0; > - dvb_unregister_frontend wait on "fepriv->dvbdev->wait_queue" that > fepriv->dvbdev->users==-1. > The user finish : > - dvb_frontend_release - set users to -1 > - don't wait wait_queue because fepriv->exit != 1 > > => dvb_unregister_frontend never exit the wait queue. > > > Matthieu > > > [ 4920.484047] khubd D c2008000 0 198 2 0x00000000 > [ 4920.484056] f64c8000 00000046 00000000 c2008000 00000004 c13fa000 > c13fa000 f > 64c8000 > [ 4920.484066] f64c81bc c2008000 00000000 d9d9dce6 00000452 00000001 > f64c8000 c > 102daad > [ 4920.484075] 00100100 f64c81bc 00000286 f0a7ccc0 f0913404 f0cba404 > f644de58 f > 092b0a8 > [ 4920.484084] Call Trace: > [ 4920.484102] [] ? default_wake_function+0x0/0x8 > [ 4920.484147] [] ? dvb_unregister_frontend+0x95/0xcc [dvb_core] > [ 4920.484157] [] ? autoremove_wake_function+0x0/0x2d > [ 4920.484168] [] ? dvb_usb_adapter_frontend_exit+0x12/0x21 > [dvb_usb] > [ 4920.484176] [] ? dvb_usb_exit+0x26/0x88 [dvb_usb] > [ 4920.484184] [] ? dvb_usb_device_exit+0x3a/0x4a [dvb_usb] > [ 4920.484217] [] ? usb_unbind_interface+0x3f/0xb4 [usbcore] > [ 4920.484227] [] ? __device_release_driver+0x74/0xb7 > [ 4920.484233] [] ? device_release_driver+0x15/0x1e > [ 4920.484243] [] ? bus_remove_device+0x6e/0x87 > [ 4920.484249] [] ? device_del+0xfa/0x152 > [ 4920.484264] [] ? usb_disable_device+0x59/0xb9 [usbcore] > [ 4920.484279] [] ? usb_disconnect+0x70/0xdc [usbcore] > [ 4920.484294] [] ? hub_thread+0x521/0xe1d [usbcore] > [ 4920.484301] [] ? autoremove_wake_function+0x0/0x2d > [ 4920.484316] [] ? hub_thread+0x0/0xe1d [usbcore] > [ 4920.484321] [] ? kthread+0x61/0x66 > [ 4920.484327] [] ? kthread+0x0/0x66 > [ 4920.484336] [] ? kernel_thread_helper+0x7/0x10 > Here a patch that fix the issue Signed-off-by: Matthieu CASTET --------------060505080405020005080704 Content-Type: text/x-diff; name="frontend_release.diff" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="frontend_release.diff" --- 1/linux/drivers/media/dvb/dvb-core/dvb_frontend.c 2010-03-27 22:59:50.000000000 +0100 +++ 2/linux/drivers/media/dvb/dvb-core/dvb_frontend.c 2010-03-27 23:01:34.000000000 +0100 @@ -686,7 +686,10 @@ } fepriv->thread = NULL; - fepriv->exit = 0; + if (kthread_should_stop()) + fepriv->exit = 2; + else + fepriv->exit = 0; mb(); dvb_frontend_wakeup(fe); @@ -1929,6 +1932,8 @@ int ret; dprintk ("%s\n", __func__); + if (fepriv->exit == 2) + return -ENODEV; if (adapter->mfe_shared) { mutex_lock (&adapter->mfe_lock); @@ -2021,7 +2026,7 @@ ret = dvb_generic_release (inode, file); if (dvbdev->users == -1) { - if (fepriv->exit == 1) { + if (fepriv->exit) { fops_put(file->f_op); file->f_op = NULL; wake_up(&dvbdev->wait_queue); --------------060505080405020005080704--