kern/146031: [snd_hda] race condition when kldunload snd_hda sound called

Garrett Cooper gcooper at
Sun Apr 25 23:40:04 UTC 2010

The following reply was made to PR kern/146031; it has been noted by GNATS.

From: Garrett Cooper <gcooper at>
To: Alexander Best <alexbestms at>
Cc: bug-followup at
Subject: Re: kern/146031: [snd_hda] race condition when kldunload snd_hda 
	sound called
Date: Sun, 25 Apr 2010 16:31:24 -0700

 On Sun, Apr 25, 2010 at 4:26 AM, Alexander Best <alexbestms at> wrote:
 > running
 > sh -c 'i=1; while [ 1 ] ; do echo "Try $i"; kldload snd_hda; kldunload snd_hda
 > sound; : $(( i += 1 )); done'
 > complains about sound.ko not being loaded, since unloading snd_hda.ko also
 > unloads sound.ko. is this what you got too?
 > i'm not sure this logic is correct. loading snd_hda.ko also loads sound.ko,
 > since it depends on it. however i don't see why unloading snd_hda.ko also
 > unloads sound.ko, since sound.ko has no dependencies and can exist without any
 > snd_*.ko module.
 > i wasn't able to trigger the panic however (command cancelled with i=350 or
 > so).
 > i'm running 9-CURRENT (r207154).
 Hi Alexander,
     1. How many cores and processors does your machine have?
     2. Do you have SMP enabled?

More information about the freebsd-multimedia mailing list