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V4L/DVB (9029): Fix deadlock in demux code 

The functions dvb_dmxdev_section_callback, dvb_dmxdev_ts_callback,
dvb_dmx_swfilter_packet, dvb_dmx_swfilter_packets, dvb_dmx_swfilter and
dvb_dmx_swfilter_204 may be called from both interrupt and process
context. Therefore they need to be protected by spin_lock_irqsave()
instead of spin_lock().

This fixes a deadlock discovered by lockdep.

Signed-off-by: Andreas Oberritter <obi@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
This commit is contained in:
Andreas Oberritter 2008-09-24 05:00:37 -03:00 committed by Mauro Carvalho Chehab
parent 3d843c92da
commit dda06a8e46
2 changed files with 19 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
drivers/media/dvb/dvb-core/dmxdev.c
View File

@ -364,15 +364,16 @@ static int dvb_dmxdev_section_callback(const u8 *buffer1, size_t buffer1_len,
enum dmx_success success)
{
struct dmxdev_filter *dmxdevfilter = filter->priv;
unsigned long flags;
int ret;
if (dmxdevfilter->buffer.error) {
wake_up(&dmxdevfilter->buffer.queue);
return 0;
}
spin_lock(&dmxdevfilter->dev->lock);
spin_lock_irqsave(&dmxdevfilter->dev->lock, flags);
if (dmxdevfilter->state != DMXDEV_STATE_GO) {
spin_unlock(&dmxdevfilter->dev->lock);
spin_unlock_irqrestore(&dmxdevfilter->dev->lock, flags);
return 0;
}
del_timer(&dmxdevfilter->timer);
@ -391,7 +392,7 @@ static int dvb_dmxdev_section_callback(const u8 *buffer1, size_t buffer1_len,
}
if (dmxdevfilter->params.sec.flags & DMX_ONESHOT)
dmxdevfilter->state = DMXDEV_STATE_DONE;
spin_unlock(&dmxdevfilter->dev->lock);
spin_unlock_irqrestore(&dmxdevfilter->dev->lock, flags);
wake_up(&dmxdevfilter->buffer.queue);
return 0;
}
@ -403,11 +404,12 @@ static int dvb_dmxdev_ts_callback(const u8 *buffer1, size_t buffer1_len,
{
struct dmxdev_filter *dmxdevfilter = feed->priv;
struct dvb_ringbuffer *buffer;
unsigned long flags;
int ret;
spin_lock(&dmxdevfilter->dev->lock);
spin_lock_irqsave(&dmxdevfilter->dev->lock, flags);
if (dmxdevfilter->params.pes.output == DMX_OUT_DECODER) {
spin_unlock(&dmxdevfilter->dev->lock);
spin_unlock_irqrestore(&dmxdevfilter->dev->lock, flags);
return 0;
}
@ -417,7 +419,7 @@ static int dvb_dmxdev_ts_callback(const u8 *buffer1, size_t buffer1_len,
else
buffer = &dmxdevfilter->dev->dvr_buffer;
if (buffer->error) {
spin_unlock(&dmxdevfilter->dev->lock);
spin_unlock_irqrestore(&dmxdevfilter->dev->lock, flags);
wake_up(&buffer->queue);
return 0;
}
@ -428,7 +430,7 @@ static int dvb_dmxdev_ts_callback(const u8 *buffer1, size_t buffer1_len,
dvb_ringbuffer_flush(buffer);
buffer->error = ret;
}
spin_unlock(&dmxdevfilter->dev->lock);
spin_unlock_irqrestore(&dmxdevfilter->dev->lock, flags);
wake_up(&buffer->queue);
return 0;
}

16
drivers/media/dvb/dvb-core/dvb_demux.c
View File

@ -399,7 +399,9 @@ static void dvb_dmx_swfilter_packet(struct dvb_demux *demux, const u8 *buf)
void dvb_dmx_swfilter_packets(struct dvb_demux *demux, const u8 *buf,
size_t count)
{
spin_lock(&demux->lock);
unsigned long flags;
spin_lock_irqsave(&demux->lock, flags);
while (count--) {
if (buf[0] == 0x47)
@ -407,16 +409,17 @@ void dvb_dmx_swfilter_packets(struct dvb_demux *demux, const u8 *buf,
buf += 188;
}
spin_unlock(&demux->lock);
spin_unlock_irqrestore(&demux->lock, flags);
}
EXPORT_SYMBOL(dvb_dmx_swfilter_packets);
void dvb_dmx_swfilter(struct dvb_demux *demux, const u8 *buf, size_t count)
{
unsigned long flags;
int p = 0, i, j;
spin_lock(&demux->lock);
spin_lock_irqsave(&demux->lock, flags);
if (demux->tsbufp) {
i = demux->tsbufp;
@ -449,17 +452,18 @@ void dvb_dmx_swfilter(struct dvb_demux *demux, const u8 *buf, size_t count)
}
bailout:
spin_unlock(&demux->lock);
spin_unlock_irqrestore(&demux->lock, flags);
}
EXPORT_SYMBOL(dvb_dmx_swfilter);
void dvb_dmx_swfilter_204(struct dvb_demux *demux, const u8 *buf, size_t count)
{
unsigned long flags;
int p = 0, i, j;
u8 tmppack[188];
spin_lock(&demux->lock);
spin_lock_irqsave(&demux->lock, flags);
if (demux->tsbufp) {
i = demux->tsbufp;
@ -500,7 +504,7 @@ void dvb_dmx_swfilter_204(struct dvb_demux *demux, const u8 *buf, size_t count)
}
bailout:
spin_unlock(&demux->lock);
spin_unlock_irqrestore(&demux->lock, flags);
}
EXPORT_SYMBOL(dvb_dmx_swfilter_204);