Re: [PATCH] PM: Acquire device locks on suspend

On Saturday, 5 of January 2008, Alan Stern wrote:

On Sat, 5 Jan 2008, Rafael J. Wysocki wrote:

quoted

quoted

Another thing to watch out for: Just in case somebody ends up calling
destroy_suspended_device(dev) from within dev's own resume method, you 
should interchange the resume_device() and the list_move_tail() 
calls in dpm_resume().

However, if we unregister them all at once after releasing pm_sleep_rwsem,
that shouldn't be necessary, right?

It's still necessary, because destroy_suspended_device() still has to
move the device from one list to another.  You don't want it to end up 
on the dpm_locked list.

Hmm.  That means we'd have to do the same thing in dpm_power_up() in case
someone calls destroy_suspended_device() from resume_device_early(dev).

Still, even doing that is not enough, since someone can call
destroy_suspended_device() from a .suspend() routine and then the device
will end up on a wrong list just as well.

Greetings,
Rafael