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perf sched: Avoid union type punning undefined behavior

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A union is used to set the priv value in thread (a void*) to a boolean
value through type punning. Undefined behavior sanitizer fails on this.

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Ian Rogers 2025-09-14 11:33:53 -07:00 committed by Arnaldo Carvalho de Melo
parent 241f21be7d
commit 58a606149c
1 changed files with 4 additions and 15 deletions
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19
tools/perf/builtin-sched.c
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@ -1532,35 +1532,24 @@ static int process_sched_wakeup_ignore(const struct perf_tool *tool __maybe_unus
return 0; return 0;
} }
union map_priv {
void *ptr;
bool color;
};
static bool thread__has_color(struct thread *thread) static bool thread__has_color(struct thread *thread)
{ {
union map_priv priv = { return thread__priv(thread) != NULL;
.ptr = thread__priv(thread),
};
return priv.color;
} }
static struct thread* static struct thread*
map__findnew_thread(struct perf_sched *sched, struct machine *machine, pid_t pid, pid_t tid) map__findnew_thread(struct perf_sched *sched, struct machine *machine, pid_t pid, pid_t tid)
{ {
struct thread *thread = machine__findnew_thread(machine, pid, tid); struct thread *thread = machine__findnew_thread(machine, pid, tid);
union map_priv priv = { bool color = false;
.color = false,
};
if (!sched->map.color_pids || !thread || thread__priv(thread)) if (!sched->map.color_pids || !thread || thread__priv(thread))
return thread; return thread;
if (thread_map__has(sched->map.color_pids, tid)) if (thread_map__has(sched->map.color_pids, tid))
priv.color = true; color = true;
thread__set_priv(thread, priv.ptr); thread__set_priv(thread, color ? ((void*)1) : NULL);
return thread; return thread;
} }