Messages in this thread | | | Subject | Re: [PATCH RESEND 2/2] Fix some kallsyms_lookup() vs rmmod races | From | Rusty Russell <> | Date | Sat, 17 Mar 2007 20:37:18 +1100 |
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On Fri, 2007-03-16 at 12:51 +0100, Ingo Molnar wrote: > * Alexey Dobriyan <adobriyan@sw.ru> wrote: > > > [cc'ing folks whose proc files are affected] > > > > kallsyms_lookup() can call module_address_lookup() which iterates over > > modules list without module_mutex taken. Comment at the top of > > module_address_lookup() says it's for oops resolution so races are > > irrelevant, but in some cases it's reachable from regular code: > > looking at the problem from another angle: wouldnt this be something > that would benefit from freeze_processes()/unfreeze_processes(), and > hence no locking would be required?
Actually, the list manipulation is done with stop_machine for this reason. Alexey, is preempt enabled in your kernel?
Rusty.
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