Re: modprobe + request_module() deadlock

[Takashi Iwai <tiwai@suse.de>]

At Thu, 18 Nov 2004 14:55:22 +0100,
Johannes Stezenbach wrote:
> 
> On Thu, Nov 18, 2004 at 02:48:22PM +1100, Rusty Russell wrote:
> > On Wed, 2004-11-17 at 23:29 +0100, Johannes Stezenbach wrote:
> > > Hi,
> > > 
> > > it seems that modprobe in newer versions of module-init-tools
> > > (here: 3.1-pre6) gets an exclusive lock on the module's .ko file:
> > > 
> > >                 struct flock lock;
> > >                 lock.l_type = F_WRLCK;
> > >                 lock.l_whence = SEEK_SET;
> > >                 lock.l_start = 0;
> > >                 lock.l_len = 1;
> > >                 fcntl(fd, F_SETLKW, &lock);
> > > 
> > > This leads to a deadlock when the loaded module calls
> > > request_module() in its module_init() function, to load
> > > a module which in turn depends on the first module.
> > 
> > My bug, I think.  Does this help?
> 
> Yes and no. The deadlock is gone, but now I get:

IIRC, request_module() in module_init() doesn't work any more in
general.

A weak linking like i2c doesn't provide the module dependency, so
modprobe can't load it by itself, so far.  I see the same problem in
ALSA snd-powermac module.

Can we add a module dependency manually somehow?

--
Takashi Iwai <tiwai@suse.de>		ALSA Developer - www.alsa-project.org