On Sun, 2009-06-28 at 15:25 +0400, Abylai Ospan wrote: > Mauro, > > Please pulll changes: > > http://udev.netup.ru/cgi-bin/hgwebdir.cgi/v4l-dvb-aospan/rev/8b0c92aec325 > > vmalloc to kmalloc changed. Since MAX_PID is only 8 kB and kmalloc can handle up to 128 kB, that seems OK. > vmalloc don't work (kernel oops hapens) when dvb_dmx_swfilter_packets > called from IRQ handler ( for example in budget-core ). No one should call dvb_dmx_swfilter_packets() from an IRQ handler. That function does too much work to finish in a short amount of time. I see budget-core.c:vpeirq(), actually gets called from a tasklet (softirq context) though. Here's a LKML thread where Andrew Morton says it's unsafe to call __vmalloc() from IRQ contexts: http://lkml.org/lkml/2008/11/17/23 Since tasklets run in an interrupt context, with many (all?) of the limitations of a IRQ handler, I suspect Andrew's comments may apply to tasklets as well. What really needs to be fixed is linux/drivers/media/dvb/ttpci/budget-core.c:vpeirq() should not call dvb_dmx_swfilter_packets() from a tasklet context, but instead from a work handler handler context. That means converting from a tasklet to a work handler. A change to the dvb-core to use kmalloc() is just avoiding the work of coverting from tasklets to workqueues. It looks like the move to replace tasklets with workqueues is at least 2 years old: http://lwn.net/Articles/239633/ BTW, it looks like av7110.c has a similar problem using a tasklet to call dvb_dmx_swfilter_packets(). Regards, Andy -- 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
