segfault on coffee lake

[d-we]

Hello,

running most pcm utilities (e.g. pcm-core.x or pcm-latency.x) on my i7-9750H results in a segfault:

-> % sudo ./pcm-core.x
IBRS and IBPB supported  : yes
STIBP supported          : yes
Spec arch caps supported : no
Number of physical cores: 6
Number of logical cores: 12
Number of online logical cores: 12
Threads (logical cores) per physical core: 2
Num sockets: 1
Physical cores per socket: 6
Core PMU (perfmon) version: 4
Number of core PMU generic (programmable) counters: 3
Width of generic (programmable) counters: 48 bits
Number of core PMU fixed counters: 3
Width of fixed counters: 48 bits
Nominal core frequency: 2600000000 Hz
IBRS enabled in the kernel   : no
STIBP enabled in the kernel  : no
Package thermal spec power: 45 Watt; Package minimum power: 0 Watt; Package maximum power: 0 Watt;

 Processor Counter Monitor: Core Monitoring Utility

WARNING: you did not provide any custom events, is this intentional?
Trying to use Linux perf events...
Successfully programmed on-core PMU using Linux perf
DEBUG: caught signal to interrupt (Segmentation fault).

backtrace:

[#0] 0x5555555724fd → std::vector<UncorePMU, std::allocator<UncorePMU> >::operator[](this=0x0, __n=0x0)
[#1] 0x5555555724fd → PCM::programCbo(nc_=<optimized out>, llc_lookup_tid_filter=<optimized out>, loc=<optimized out>, rem=<optimized out>, opCode=<optimized out>, events=<optimized out>, this=<optimized out>)
[#2] 0x5555555724fd → PCM::programCbo(this=0x5555555d7eb0)
[#3] 0x555555592a81 → PCM::program(this=0x5555555d7eb0, mode_=<optimized out>, parameter_=<optimized out>)
[#4] 0x555555565926 → build_registers(m=0x5555555d7eb0, conf={
  fixedCfg = 0x0,
  nGPCounters = 0x2,
  gpCounterCfg = 0x5555555c55f0 <regs>,
  OffcoreResponseMsrValue = {0x0, 0x0}
}, enable_pmm=<optimized out>, enable_verbose=<optimized out>)
[#5] 0x55555556030b → main(argc=0x1, argv=<optimized out>)

[opcm]

Thanks for reporting this issue. The latest commit d41c991
in master should fix this issue. Are you using the latest version from the master branch?

[opcm]

It is very similar to #185

[d-we]

I just verified the bug on the up-to-date master (c7899c9) but I just observed that the bug only seems to appear when I run the utilities with non-root users.
Running as root I only get:

Detected Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz "Intel(r) microarchitecture codename Kabylake" stepping 10 microcode level 0xc6
Platform not Supported! Program aborted
Cleaning up
 Zeroed uncore PMU registers

which I assume means that my CPU doesn't support PCM?

[opcm]

Your CPU is not supported by the pcm-latency tool. pcm tool should work. But crashing as a non-root is not expected and it is a different issue that needs to be resolved.

[opcm]

the fix for the crash has been merged into the master branch