From cc956e0cd6a405fbc6ad3055cbbdb178562ef27d Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Wed, 7 Oct 2026 07:02:42 -0300 Subject: perf evsel: Mark the event as supported when retrying an open Opening a group with perf record on a machine with perf_event_paranoid > 1 and no CAP_PERFMON fails the first perf_event_open() with EACCES, after which evsel__open_cpu() clears evsel->supported; evsel__fallback() then adds exclude_kernel and record__open() retries, and the retry succeeds with supported left false. get_group_fd() treats unsupported events as ungroupable, so the retry opens the group members without their leader: sys_perf_event_open: pid 12345 cpu 0 group_fd -1 FAILED '.../test-record-group-sampling1' - group failure which fails the group subtests of "perf test 82", the Perf attribute expectations test, when it is run as a regular user, while it passes as root or with CAP_PERFMON, where the first open doesn't fail. commit 2cc7aa995ce9 ("perf stat: Refactor retry/skip/fatal error handling") dropped the pos->supported = true that record__open() did after a successful open and moved the resets into the stat code only, while saying "When an event is tried the supported is set to true again". Do that in evsel__open_cpu(), which every open entry point funnels through, so that a retry describes its own try instead of the previous failure. Fixes: 2cc7aa995ce9ecd8 ("perf stat: Refactor retry/skip/fatal error handling") Reviewed-by: Ian Rogers Tested-by: Ian Rogers Cc: Ian Rogers Assisted-by: LLM Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/evsel.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index 9c5e7510f0c0..e61f309e93dc 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -3014,6 +3014,12 @@ static int evsel__open_cpu(struct evsel *evsel, struct perf_cpu_map *cpus, enum rlimit_action set_rlimit = NO_CHANGE; struct perf_cpu cpu; + /* + * A failed attempt being retried after evsel__fallback() would + * otherwise keep group members out of their group in get_group_fd(). + */ + evsel->supported = true; + if (evsel__is_retire_lat(evsel)) { err = evsel__tpebs_open(evsel); goto out; -- cgit v1.2.3