[alsa-devel] sound: WARNING in snd_rawmidi_kernel_write1

[Takashi Iwai]

On Tue, 02 Feb 2016 22:25:45 +0100,
Dmitry Vyukov wrote:
> 
> On Mon, Feb 1, 2016 at 11:36 AM, Takashi Iwai <tiwai at suse.de> wrote:
> > On Mon, 01 Feb 2016 11:15:08 +0100,
> > Dmitry Vyukov wrote:
> >>
> >> Hello,
> >>
> >> The following program triggers WARNING in snd_rawmidi_kernel_write1:
> >>
> >> // autogenerated by syzkaller (http://github.com/google/syzkaller)
> >> #include <unistd.h>
> >> #include <sys/types.h>
> >> #include <sys/stat.h>
> >> #include <sys/uio.h>
> >> #include <fcntl.h>
> >>
> >> int main()
> >> {
> >>   int fd;
> >>   struct iovec iov;
> >>
> >>   fd = open("/dev/snd/midiC3D0", O_RDWR);
> >
> > What is the 3rd device?  Please show /proc/asound/cards content.
> 
> Missed this question. Here is it. I run qemu with "-soundhw all" flag.
> 
>  0 [Dummy          ]: Dummy - Dummy
>                       Dummy 1
>  1 [Loopback       ]: Loopback - Loopback
>                       Loopback 1
>  2 [VirMIDI        ]: VirMIDI - VirMIDI
>                       Virtual MIDI Card 1
>  3 [port           ]: MTPAV - MTPAV on parallel port
>                       MTPAV on parallel port at 0x378
>  4 [pcsp           ]: PC-Speaker - pcsp
>                       Internal PC-Speaker at port 0x61
>  5 [Intel          ]: HDA-Intel - HDA Intel
>                       HDA Intel at 0xfebf0000 irq 24
> 
> But the patch helps with the warning message :)

Ah, you enabled MTPAV driver.  Please drop CONFIG_SND_MTPAV for your
testing.  This is known to be unstable and is only for a dedicated
parport device, not meant as a generic device to be covered at all.


Takashi