Messages in this thread | | | Date | Mon, 28 Nov 2005 13:07:11 +0100 | From | Andi Kleen <> | Subject | Re: [Lse-tech] Re: [PATCH 0/7]: Fix for unsafe notifier chain |
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On Mon, Nov 28, 2005 at 07:31:36PM +1100, Keith Owens wrote: > On Mon, 28 Nov 2005 05:59:22 +0100, > Andi Kleen <ak@suse.de> wrote: > >On Sun, Nov 27, 2005 at 08:57:45PM -0800, Andrew Morton wrote: > >> "Paul E. McKenney" <paulmck@us.ibm.com> wrote: > >> > > >> > Any options I missed? > >> > >> Stop using the notifier chains from NMI context - it's too hard. Use a > >> fixed-size array in the NMI code instead. > > > >Or just don't unregister. That is what I did for the debug notifiers. > > Unregister is not the only problem. Chain traversal races with > register as well.
Either it follows the old next or the new next. Both are valid. The only problem is that there isn't a write barrier between
n->next = *list; *list=n;
in notifier_chain_register, which might hit on non i386 architectures.
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