Messages in this thread |  | | | Date | Tue, 24 Jan 2006 23:10:52 -0800 | | From | Andrew Morton <> | | Subject | Re: [PATCH 1/5] stack overflow safe kdump (2.6.16-rc1-i386) - safe_smp_processor_id |
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Fernando Luis Vazquez Cao <fernando@intellilink.co.jp> wrote: > > On the event of a stack overflow critical data that usually resides at > the bottom of the stack is likely to be stomped and, consequently, its > use should be avoided. > > In particular, in the i386 and IA64 architectures the macro > smp_processor_id ultimately makes use of the "cpu" member of struct > thread_info which resides at the bottom of the stack. x86_64, on the > other hand, is not affected by this problem because it benefits from > the use of the PDA infrastructure. > > To circumvent this problem I suggest implementing > "safe_smp_processor_id()" (it already exists in x86_64) for i386 and > IA64 and use it as a replacement for smp_processor_id in the reboot path > to the dump capture kernel. This is a possible implementation for i386. > > ... > > +int safe_smp_processor_id(void) {
Please fix coding style.
> #endif > > +extern int safe_smp_processor_id(void); > extern int __cpu_disable(void); > extern void __cpu_die(unsigned int cpu); > #endif /* !__ASSEMBLY__ */ > > #else /* CONFIG_SMP */ > > +#define safe_smp_processor_id() 0 > #define cpu_physical_id(cpu) boot_cpu_physical_apicid
It assumes that all x86 SMP machines have APICs. That's untrue of Voyager. I think we can probably live with this assumption - others would know better than I. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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