| To: | "Jan Beulich" <jbeulich@xxxxxxxxxx> |
|---|---|
| Subject: | Re: [Xen-devel] memguard_guard_stack() |
| From: | Keir Fraser <Keir.Fraser@xxxxxxxxxxxx> |
| Date: | Mon, 1 May 2006 15:09:19 +0100 |
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| Delivery-date: | 2006年5月01日 07:09:33 -0700 |
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On 1 May 2006, at 12:36, Jan Beulich wrote:
Hmm, but I found this precisely because we saw a double fault due to a stack overflow. Admittedly this was in the context of one of these IPI storms during shotdown that were fixed previously, but even that shouldn't result in a stackHow many CPUs were in the system? That code path was rather dodgy: the function forcibly enabled interrupts and so a single CPU could nest in that function up to (NR_CPUS-1) times which, if you had say 32 CPUs in the system could certainly cause problems. I don't think it's indicative of a wider problem in Xen -- for most interrupts (ones bound to a guest) we don't even reenable interrupt delivery while handling them, so nested ISRs in Xen are impossible. I would like to understand exactly what happened in the context of your IPI storm (it *is* the machine restart bug we're talking about, right?) -- if you had much fewer than 32 CPUs then I need to check exactly how much stack an invocation of machine_restart() uses.overflow, should it ? Jan
-- Keir _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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