non-sleepable locks held

[Don Lewis]

On  7 Feb, David Xu wrote:
> I got following messages on console:
> 
> 
> malloc() of "256" with the following non-sleepable locks held:
> exclusive sleep mutex pcm0 (sound cdev) r = 0 (0xc3800600) locked @ 
> /usr/home/davidxu/src/sys/dev/sound/pcm/dsp.c:213

It would be nice to have a stack trace for this error.  I think the
error below is unrelated.  What sound driver are you using?

> lock order reversal
>   1st 0xc3b85a38 filedesc structure (filedesc structure) @ 
> kern/sys_generic.c:901
>   2nd 0xc0927ca0 Giant (Giant) @ fs/specfs/spec_vnops.c:377
> Stack backtrace:
> backtrace(c086e5e9,c0927ca0,c086a64a,c086a64a,c0865c89) at backtrace+0x17
> witness_checkorder(c0927ca0,9,c0865c89,179,1) at witness_checkorder+0x6f8
> _mtx_lock_flags(c0927ca0,0,c0865c80,179,c086ec03) at _mtx_lock_flags+0x9d
> spec_poll(d7658afc,d7658b1c,c06aad6c,d7658afc,c0909e20) at spec_poll+0x134
> spec_vnoperate(d7658afc,c0909e20,c390a30c,40,c3c37b00) at 
> spec_vnoperate+0x18
> vn_poll(c3ebbd8c,40,c4010180,c383b540,c4010180) at vn_poll+0x3c
> selscan(c383b540,d7658b9c,d7658b8c,9,4) at selscan+0x141
> kern_select(c383b540,9,80692b0,80692c0,0) at kern_select+0x37f
> select(c383b540,d7658d14,14,438,5) at select+0x66
> syscall(2f,2f,2f,3,0) at syscall+0x2a0
> Xint0x80_syscall() at Xint0x80_syscall+0x1d
> --- syscall (93), eip = 0x282a28ab, esp = 0xbfbfe6cc, ebp = 0xbfbfe778 ---