Messages in this thread | | | Date | Sat, 27 Jun 1998 17:31:06 -0700 | From | Richard Henderson <> | Subject | Re: pre-patch-2.1.107 breaks kmod |
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On Sat, Jun 27, 1998 at 12:46:41PM +1000, Keith Owens wrote: > Aren't we missing something here? insmod is not the only thing that > hits loaded modules, rmmod does as well. Consider the race > > insmod x.o > insmod x.o rmmod x.o in parallel
Why in the world are you concerned about this? Rmmod already serializes "fine" with insmod. In that the kernel keeps the data structures in a sane state, but that the users of said modules are bound to loose no matter what.
> Using an flock scheme, the second insmod waits for the flock and holds > until the first insmod completes. Then it checks if the module has > been loaded while it was waiting, yes the module is there, return OK.
Um, no, that's not what it does. It waits for the lock, tries to create the module, and if that fails with EEXIST, returns OK.
But rmmod has always been able to remove an embryonic module before insmod can fully initialize it -- how else can one clean up after insmod faults? So there are more insmod/rmmod "races" than you imagine.
"Doc, it hurts when I do this." "Don't do that."
r~
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