[ofa-general] Race condition in core/sysfs.c (kernel panic) when unloading the driver

[Roland Dreier]

 > I'm not sure that it does.  This does not make sysfs access atomic wrt module unloading.
 > I think an app can still lose it's timeslice while inside the sysfs access, and module
 > unload can still occur while the app is waiting for a new time slice (although the code pages
 > will not be removed as yet -- see below).

Not sure I follow... the low-level driver must handle requests until
ib_unregister_device() returns, and with the change I proposed,
ib_unregister_device() will not return until all sysfs files are gone
(and no open file handles remain).

 > What about the patch I just submitted?

I'd rather not add a superfluous mutex that adds complexity when a
simpler solution is available.

 - R.