From cda5a94ad9181cd60cbf04be11d524201bf489a2 Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Fri, 5 Jun 2026 11:12:08 -0300 Subject: [PATCH] perf sched: Clean up idle_threads entry on init failure get_idle_thread() allocates a thread via thread__new() and stores it in idle_threads[cpu], then calls init_idle_thread() to set up the private data. If init_idle_thread() fails (e.g. OOM for the idle_thread_runtime struct), the function returns NULL but leaves the partially initialized thread in idle_threads[cpu]. On subsequent calls for the same CPU, get_idle_thread() finds a non-NULL idle_threads[cpu], skips allocation, and returns thread__get() on a thread that has no priv data. Callers then get a thread whose thread__priv() returns NULL, leading to unexpected behavior. Release the thread and reset the slot to NULL on init failure so the entry doesn't persist in a corrupted state. Fixes: 49394a2a24c7 ("perf sched timehist: Introduce timehist command") Reported-by: sashiko-bot Cc: David Ahern Cc: Namhyung Kim Assisted-by: Claude:claude-opus-4.6 Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-sched.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c index 21fb820b625b4..e4378cc9ab3ed 100644 --- a/tools/perf/builtin-sched.c +++ b/tools/perf/builtin-sched.c @@ -2514,8 +2514,11 @@ static struct thread *get_idle_thread(int cpu) idle_threads[cpu] = thread__new(0, 0); if (idle_threads[cpu]) { - if (init_idle_thread(idle_threads[cpu]) < 0) + if (init_idle_thread(idle_threads[cpu]) < 0) { + /* clean up so next call doesn't find a half-initialized thread */ + thread__zput(idle_threads[cpu]); return NULL; + } } } -- 2.47.3