Re: [PATCH] perf evsel: Restrict incremental open error unwind

[sashiko-bot@kernel.org]

> evsel__open_cpu(), evsel__tool_pmu_open() and
> evsel__hwmon_pmu_open() support opening a subrange of a CPU map, bounded
> by [start_cpu_map_idx, end_cpu_map_idx).
> 
> Their error paths, however, unwind using "while (--idx >= 0)" all the way
> back to CPU index 0 regardless of start_cpu_map_idx. If lower CPU indices
> were opened by an earlier invocation, a later incremental open failure
> therefore closes those existing file descriptors and overwrites their
> slots with -1.
> 
> Before this fix, running the new incremental open test demonstrates this
> corruption:
> 
>   $ perf test -v "Tool PMU"
>    12: Tool PMU:
> [ ... ]
> 
> Fixes: 4804e0111662 ("perf stat: Use affinity for opening events")
> Fixes: 240505b2d0ad ("perf tool_pmu: Factor tool events into their own PMU")
> Fixes: 53cc0b351ec9 ("perf hwmon_pmu: Add a tool PMU exposing events from hwmon in sysfs")
> Signed-off-by: Hui Su <sh_def@163.com>

Sashiko has reviewed this patch and found no issues. It looks great!

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260912031112.1814574-1-sh_def@163.com?part=1