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. >
You know, seems I got what happened -- p4_general_events do not cover all general events, they stop at PERF_COUNT_HW_BUS_CYCLES, while more 3 general event left. This is 'cause I've not been following pmu evolution in code. I will try to cover this events hopefully more less soon and send you a patch to test (if you don't mind).