Messages in this thread | | | Date | Wed, 3 Apr 2019 18:13:18 +0300 | From | Cyrill Gorcunov <> | Subject | Re: perf: perf_fuzzer crashes on Pentium 4 systems |
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On Wed, Apr 03, 2019 at 10:59:32AM -0400, Vince Weaver wrote: > > so moving this to its own thread. > > There was a two-part question asked. > 1. Can the perf-fuzzer crash a Pentium 4 system > 2. Does anyone care anymore? > > The answer to #1 turns out to be "yes" > I'm not sure about #2 (but it's telling my p4 test system hadn't been > turned on in over 3 years). > > In any case the perf_fuzzer can crash my p4 system within an hour or so. > The debugging from this isn't great, I forget what the preferred debug > things to enable in the kernel hacking menu are. > > Here is one crash that just happened: > > The instruction at RIP is unhelpfully > ./arch/x86/include/asm/processor.h:400 > which is > DECLARE_PER_CPU_FIRST(union irq_stack_union, irq_stack_union) __visible; > > Though looking at the assembly it looks like > p4_pmu_enable_event() is called with NULL as the paramater. >
Interesting! I'll look more carefully at evening. As far as I remember we rely on active_mask bit set completely, not sure how it could happen that we get nil here. Thanks for pointing!
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