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Date: Wed, 30 Jul 2008 13:04:50 +1000 From: Rusty Russell <rusty@...tcorp.com.au> To: Mathieu Desnoyers <mathieu.desnoyers@...ymtl.ca> Cc: "Frank Ch. Eigler" <fche@...hat.com>, linux-kernel@...r.kernel.org, akpm@...ux-foundation.org Subject: Re: [PATCH] Module : call synchronize_sched() between module exit() and free. On Wednesday 30 July 2008 12:27:51 Mathieu Desnoyers wrote: > > Hi Mathieu, > > > > Yes: stop_machine is merely used to atomically check the module > > refcount for zero and set the state so it can't be incremented again (ie. > > try_module_get will fail). > > > > So placing a tracepoint or marker in a module does not bump the module > > refcount? If that's true, then there needs to be some kind of > > remove_markers_from_module() call after module->exit(), which should do > > the synchronize_sched() or whatever, right? > > > > Rusty. > > Actually, it's not placing a marker/tracepoint in a module which causes > a problem, this is a simple function call after all, and correctly dealt > with by current module.c code. > > The problem comes from a probe function (the callback) that would be > registered to be called from a marker and would sit in an unloadable > kernel module. I would not want to tie the refcount of the probe modules > to the fact that they are connected to a marker because it would then > become impossible to unload them due to the fact that unregistration is > done in module exit(). Hi Mathieu, Still confused, sorry. Why don't you don't do a synchronize_sched() at the end of your module's exit routine? "You must be completely finished by the time ->exit() returns" is the rule so far... Rusty. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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