Re: Locking Between User Context and Soft IRQs in 2.4.0

Jeff Garzik
2000-11-04T17:08:10Z

Andi Kleen wrote:
> All the MOD_INC/DEC_USE_COUNT are done inside the modules themselves. There
> is nothing that would a driver prevent from being unloaded on a different
> CPU while it is already executing in ->open but has not yet executed the add
> yet or after it has executed the _DEC but it is still running in module code
> Normally the windows are pretty small, but very long running interrupt
> on one CPU hitting exactly in the wrong moment can change that.

Module unload calls unregister_netdev, which grabs rtnl_lock.
dev->open runs under rtnl_lock.

Given this, how can the driver be unloaded if dev->open is running?

--
Jeff Garzik | Dinner is ready when
Building 1024 | the smoke alarm goes off.
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