Hi Andi, Huber Andreas wrote[1]: > [Symptom] > Processes that try to open a cx88-blackbird driven MPEG device will hang up. Thanks for reporting. Just cc-ing some relevant people. Could you file a bug to track this at <http://bugzilla.kernel.org/>, product v4l-dvb, component cx88, and then send the bug number to 619827@xxxxxxxxxxxxxxx ? Report follows. Jonathan [1] http://bugs.debian.org/619827 > [Cause] > Nestet mutex_locks (which are not allowed) result in a deadlock. > > [Details] > Source-File: drivers/media/video/cx88/cx88-blackbird.c > Function: int mpeg_open(struct file *file) > Problem: the calls to drv->request_acquire(drv); and > drv->request_release(drv); will hang because they try to lock a > mutex that has already been locked by a previouse call to > mutex_lock(&dev->core->lock) ... > > 1050 static int mpeg_open(struct file *file) > 1051 { > [...] > 1060 mutex_lock(&dev->core->lock); // MUTEX LOCKED !!!!!!!!!!!!!!!! > 1061 > 1062 /* Make sure we can acquire the hardware */ > 1063 drv = cx8802_get_driver(dev, CX88_MPEG_BLACKBIRD); > 1064 if (drv) { > 1065 err = drv->request_acquire(drv); // HANGS !!!!!!!!!!!!!!!!!!! > 1066 if(err != 0) { > 1067 dprintk(1,"%s: Unable to acquire hardware, %d\n", __func__, err); > 1068 mutex_unlock(&dev->core->lock);; > 1069 return err; > 1070 } > 1071 } > [...] > > Here's the relevant kernel log extract (Linux version 2.6.38-1-amd64 (Debian 2.6.38-1)) ... > > Mar 24 21:25:10 xen kernel: [ 241.472067] INFO: task v4l_id:1000 blocked for more than 120 seconds. > Mar 24 21:25:10 xen kernel: [ 241.478845] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > Mar 24 21:25:10 xen kernel: [ 241.482412] v4l_id D ffff88006bcb6540 0 1000 1 0x00000000 > Mar 24 21:25:10 xen kernel: [ 241.486031] ffff88006bcb6540 0000000000000086 ffff880000000001 ffff88006981c380 > Mar 24 21:25:10 xen kernel: [ 241.489694] 0000000000013700 ffff88006be5bfd8 ffff88006be5bfd8 0000000000013700 > Mar 24 21:25:10 xen kernel: [ 241.493301] ffff88006bcb6540 ffff88006be5a010 ffff88006bcb6540 000000016be5a000 > Mar 24 21:25:10 xen kernel: [ 241.496766] Call Trace: > Mar 24 21:25:10 xen kernel: [ 241.500145] [<ffffffff81321c4a>] ? __mutex_lock_common+0x127/0x193 > Mar 24 21:25:10 xen kernel: [ 241.503630] [<ffffffff81321d82>] ? mutex_lock+0x1a/0x33 > Mar 24 21:25:10 xen kernel: [ 241.507145] [<ffffffffa09dd155>] ? cx8802_request_acquire+0x66/0xc6 [cx8802] > Mar 24 21:25:10 xen kernel: [ 241.510699] [<ffffffffa0aab7f2>] ? mpeg_open+0x7a/0x1fc [cx88_blackbird] > Mar 24 21:25:10 xen kernel: [ 241.514279] [<ffffffff8123bfb6>] ? kobj_lookup+0x139/0x173 > Mar 24 21:25:10 xen kernel: [ 241.517856] [<ffffffffa062d5fd>] ? v4l2_open+0xb3/0xdf [videodev] -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
