[alsa-devel] sound: WARNING in snd_rawmidi_kernel_write1

[Dmitry Vyukov]

On Wed, Feb 3, 2016 at 12:20 AM, Takashi Iwai <tiwai at suse.de> wrote:
> 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.


Dropped CONFIG_SND_MTPAV.