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SubjectRe: perf_fuzzer compiled for x32 causes reboot
On 02/24/2014 09:25 AM, Peter Zijlstra wrote:
>> What is likely happening is the user page fault is triggering
>> code to do a "perf_callchain" dump, which is calling copy_from_user_nmi()
>> which calls copy_user_generic_string() which is somehow getting the user
>> RBP in the RDI register somehow?
> So that code very much relies on the 'recursive' NMI/iret magic from
> Steve, patch 3f3c8b8c4b2a3 (and assorted fixes later).
> If CR2 is getting corrupted; 7fbb98c5cb075 seems relevant.
> Peter, does x32 have a slightly different ABI/calling convention that
> would make any of these patches just slightly 'off'?

As long as we're talking kernel code, x32 isn't even involved (we do not
support compiling the kernel as x32 and most likely never will.)


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