Hi,
I've been "plugging away" at the locking issue in the em28xx / em28xx-dvb
modules, and I think I've found the reason. Basically, we're trying to acquire
the dev->lock mutex again in dvb_init() when we've already acquired it in
em28xx_init_dev().
The exact sequence is:
em28xx_init_dev()
- em28xx_init_extension()
-- ops->init(dev) function for each extension
where ops->init = dvb_init() for the em28xx-dvb extension. However, if you
remove the em28xx-dvb module first then the em28xx_extension_devlist is empty
and you avoid calling dvb_init().
As to the fix, I'm thinking of moving the mutex_lock() / mutex_unlock() calls
from dvb_init() to em28xx_register_extension() instead. This way, we ensure that
dvb_init() is still always called with the dvb->lock mutex held.
I'll submit a patch for review in the morning. (Or should I say, "later this
morning"...)
Cheers,
Chris
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