Re: [PATCH v2] perf test: Add test for events re-armed with PERF_EVENT_IOC_REFRESH

[sashiko-bot@kernel.org]

> Open a sampling event with sample_period 1, re-arm it with
> PERF_EVENT_IOC_REFRESH from its overflow signal handler, as
> self-profilers such as async-profiler do, and check that each of 1000
> events delivers a signal. One case uses a software event (page faults),
> the other the syscalls:sys_enter_getppid tracepoint. The signal is a
> real-time one, so overflows cannot be coalesced, and the page fault
> buffer is marked MADV_NOHUGEPAGE so that each touched page faults once.
> 
> The tracepoint case fails since
> commit 18dbcbfabfff ("perf: Fix the POLL_HUP delivery breakage"):
> only the first overflow is delivered. The re-arming ioctl succeeds,
> but the event count stays at 1. It passes on the parent commit. The
> software case passes on both.
> 
> The test was written with an AI coding assistant (Claude) from a
> standalone reproducer; I reviewed it and ran it in QEMU on current
> mainline, on that commit and on its parent.
> 
> Link: https://github.com/async-profiler/async-profiler/issues/1813
> Signed-off-by: Francesco Nigro <nigro.fra@gmail.com>

Sashiko has reviewed this patch and found no issues.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261021141736.2414170-1-nigro.fra@gmail.com?part=1