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| author | Robert Krakora <rob.krakora@messagenetsystems.com> | 2009-01-25 13:08:07 -0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2009-01-29 09:01:06 -0200 |
| commit | 9c06210b89e604aa75314d3d173a93292b0d2777 (patch) | |
| tree | a52bc35964829278f31ef237fb88ba1f8bb15d1f | |
| parent | 7f03a5856c1c32ddc7b6b7a31bd43a4ab8e29f90 (diff) | |
| download | linux-9c06210b89e604aa75314d3d173a93292b0d2777.tar.gz linux-9c06210b89e604aa75314d3d173a93292b0d2777.tar.bz2 linux-9c06210b89e604aa75314d3d173a93292b0d2777.zip | |
V4L/DVB (10325): em28xx: Fix for fail to submit URB with IRQs and Pre-emption Disabled
Trace: (Provided by Douglas)
BUG: sleeping function called from invalid context at drivers/usb/core/urb.c:558
in_atomic():0, irqs_disabled():1
Pid: 4918, comm: sox Not tainted 2.6.27.5 #1
[<c04246d8>] __might_sleep+0xc6/0xcb
[<c058c8b0>] usb_kill_urb+0x1a/0xd8
[<c0488e68>] ? __kmalloc+0x9b/0xfc
[<c0488e85>] ? __kmalloc+0xb8/0xfc
[<c058cd5a>] ? usb_alloc_urb+0xf/0x31
[<f8dd638c>] em28xx_isoc_audio_deinit+0x2f/0x6c [em28xx_alsa]
[<f8dd6573>] em28xx_cmd+0x1aa/0x1c5 [em28xx_alsa]
[<f8dd65e1>] snd_em28xx_capture_trigger+0x53/0x68 [em28xx_alsa]
[<f8aa8674>] snd_pcm_do_start+0x1c/0x23 [snd_pcm]
[<f8aa85d7>] snd_pcm_action_single+0x25/0x4b [snd_pcm]
[<f8aa9833>] snd_pcm_action+0x6a/0x76 [snd_pcm]
[<f8aa98f5>] snd_pcm_start+0x14/0x16 [snd_pcm]
[<f8aae10e>] snd_pcm_lib_read1+0x66/0x273 [snd_pcm]
[<f8aac5a3>] ? snd_pcm_kernel_ioctl+0x46/0x5f [snd_pcm]
[<f8aae4a7>] snd_pcm_lib_read+0xbf/0xcd [snd_pcm]
[<f8aad774>] ? snd_pcm_lib_read_transfer+0x0/0xaf [snd_pcm]
[<f89feeb6>] snd_pcm_oss_read3+0x99/0xdc [snd_pcm_oss]
[<f89fef9c>] snd_pcm_oss_read2+0xa3/0xbf [snd_pcm_oss]
[<c064169d>] ? _cond_resched+0x8/0x32
[<f89ff0be>] snd_pcm_oss_read+0x106/0x150 [snd_pcm_oss]
[<f89fefb8>] ? snd_pcm_oss_read+0x0/0x150 [snd_pcm_oss]
[<c048c6e2>] vfs_read+0x81/0xdc
[<c048c7d6>] sys_read+0x3b/0x60
[<c04039bf>] sysenter_do_call+0x12/0x34
=======================
The culprit in the trace is snd_pcm_action() which invokes a spin lock
which disables pre-emption which disables an IRQ which causes the
__might_sleep() function to fail the irqs_disabled() test. Since
pre-emption is enabled then it is safe to de-allocate the memory if
you first unlink each URB. In this instance you are safe since
pre-emption is disabled. If pre-emption and irqs are not disabled then
call usb_kill_urb(), else call usb_unlink_urb().
Thanks to Douglas for tracking down this bug originally!!!
[dougsland@redhat.com: Fixed codyingstyle]
Signed-off-by: Robert Krakora <rob.krakora@messagenetsystems.com>
Signed-off-by: Douglas Schilling Landgraf <dougsland@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
| -rw-r--r-- | drivers/media/video/em28xx/em28xx-audio.c | 9 | ||||
| -rw-r--r-- | drivers/media/video/em28xx/em28xx-core.c | 7 |
2 files changed, 11 insertions, 5 deletions
diff --git a/drivers/media/video/em28xx/em28xx-audio.c b/drivers/media/video/em28xx/em28xx-audio.c index fcc300c93995..5d882a44e3ee 100644 --- a/drivers/media/video/em28xx/em28xx-audio.c +++ b/drivers/media/video/em28xx/em28xx-audio.c @@ -62,12 +62,15 @@ static int em28xx_isoc_audio_deinit(struct em28xx *dev) dprintk("Stopping isoc\n"); for (i = 0; i < EM28XX_AUDIO_BUFS; i++) { - usb_kill_urb(dev->adev.urb[i]); + if (!irqs_disabled()) + usb_kill_urb(dev->adev.urb[i]); + else + usb_unlink_urb(dev->adev.urb[i]); usb_free_urb(dev->adev.urb[i]); dev->adev.urb[i] = NULL; - kfree(dev->adev.transfer_buffer[i]); - dev->adev.transfer_buffer[i] = NULL; + kfree(dev->adev.transfer_buffer[i]); + dev->adev.transfer_buffer[i] = NULL; } return 0; diff --git a/drivers/media/video/em28xx/em28xx-core.c b/drivers/media/video/em28xx/em28xx-core.c index 71ad35192c06..94fb1b639a2e 100644 --- a/drivers/media/video/em28xx/em28xx-core.c +++ b/drivers/media/video/em28xx/em28xx-core.c @@ -860,8 +860,11 @@ void em28xx_uninit_isoc(struct em28xx *dev) for (i = 0; i < dev->isoc_ctl.num_bufs; i++) { urb = dev->isoc_ctl.urb[i]; if (urb) { - usb_kill_urb(urb); - usb_unlink_urb(urb); + if (!irqs_disabled()) + usb_kill_urb(urb); + else + usb_unlink_urb(urb); + if (dev->isoc_ctl.transfer_buffer[i]) { usb_buffer_free(dev->udev, urb->transfer_buffer_length, |