RE: [PATCH 0/1] perf: fix reset interface potential failure

[Masahiko Yamada (Fujitsu)]

Dear all

> There is a potential bug where PERF_EVENT_IOC_RESET
> does not work when accessing PMU registers directly
> from userspace in the perf_event interface.
> 
> In the x86 environment, the kernel(perf_event reset handling) has a
> potential failure, but it works with the papi library side workaround.
> The PMU register direct access feature from user space was implemented in
> the perf_event facility from linux-5.18 version in the arm64 environment,
> but it does not work with the workaround on the papi library side in the
> arm64 environment.
> The workaround worked in the x86 environment and not in the arm64
> environment because in the arm64 environment, only CPU_CYCLES was
> a 64 bit counter and the rest were 32 bit counters, so the workaround
> cleared the upper 32 bits of the value measured by CPU_CYCLES.
> 
> For this reason, we have created a patch on the kernel
> that fixes a potential perf_event reset failure.

I have not received any comments or objections to this patch so far, 
but could you give me any comments on this patch?

Best regards,
Masahiko Yamada