[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH for-4.5] x86/stack: Avoid peeking into unmapped guard pages when dumping Xens stack
>>> On 04.12.14 at 13:58, <andrew.cooper3@xxxxxxxxxx> wrote: > Konrad: I am requesting a release ack for this change. It aids the clarity of > certain crash information, and prevents cascade pagefaults in certain > circumstances, which would prevent execution of the crash kernel or a system > reboot. With #ifndef NDEBUG #define MEMORY_GUARD #endif I don't think this qualifies as a necessary bug fix at this point of 4.5. > +unsigned long get_stack_trace_bottom(unsigned long sp) > +{ > + switch ( get_stack_page(sp) ) > + { > + case 0 ... 2: > + return ROUNDUP(sp, PAGE_SIZE) - > + offsetof(struct cpu_user_regs, es) - sizeof(unsigned long); The only concern I have here is that this may wrongly truncate a dump/trace when one of the IST stacks overflowed. But I think we can live with that - an overflow of the first one would already have similar behavior today. > + > +#ifndef MEMORY_GUARD > + case 3 ... 5: > +#endif > + case 6 ... 7: > + return ROUNDUP(sp, STACK_SIZE) - > + sizeof(struct cpu_info) - sizeof(unsigned long); > + > +#ifdef MEMORY_GUARD > + case 3 ... 5: > +#endif > + default: What is the #ifdef good for when this is "default:" anyway? With this dropped (also from the other function) Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx> Jan _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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