Messages in this thread | | | Subject | Re: [PATCH & RFC] kdump and stack overflows | From | Fernando Luis Vazquez Cao <> | Date | Wed, 30 Nov 2005 00:43:32 +0900 |
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On Mon, 2005-11-28 at 11:29 -0700, Eric W. Biederman wrote: > Fernando Luis Vazquez Cao <fernando@intellilink.co.jp> writes: > > > On Mon, 2005-11-28 at 06:39 -0700, Eric W. Biederman wrote: > >> Fernando Luis Vazquez Cao <fernando@intellilink.co.jp> writes: > > > Regarding the stack overflow audit of the nmi path, we have the problem > > that both nmi_enter and nmi_exit in do_nmi (see code below) make heavy > > use of "current" indirectly (specially through the kernel preemption > > code). > > Ok. I wonder if it would be saner to simply replace the nmi trap > handler on the crash dump path? That seems to be the cleanest way to solve the problem. I will write a patch implementing that and see how it works.
> >> I believe we have a separate interrupt stack that > >> should help but.. > > Yes, when using 4K stacks we have a separate interrupt stack that should > > help, but I am afraid that crash dumping is about being paranoid. > > Oh I agree. If we had a private 4K stack for the nmi handler we > would not need to worry about overflow in that case. (baring > nmi happening during nmis) Hmm. Is there anything to keep > us doing something bad in that case? I think that is a sensible thing to do. I am just back from a day off, but tomorrow I will take a closer look at this.
Regards,
Fernando
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