From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-dl1-f74.google.com (mail-dl1-f74.google.com [74.125.82.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 27DFC38AC85 for ; Thu, 2 Apr 2026 21:57:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.82.74 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775167058; cv=none; b=H4XT4NvJro3H74+AqRraidrA3+CSP4C0ioybMhVwrgGbSDpExxeRM7fN2DTgTLuTY4b9F35UG1xP12uEo7LRnn7LKtYkI2TpZ3zuHFSwjmwU5aQHgmq//N7+PZKZOjYG7dHVfb2CR+sUX2I/Vg1t33HxrpiLle/YcHM2A/R64xY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775167058; c=relaxed/simple; bh=siRI0ffl20AQmueI8A3TOxwowDSSjh9DIdAqWO1oi/E=; h=Date:Mime-Version:Message-ID:Subject:From:To:Content-Type; b=tnuKH8ZkBNFqUH5g3wkI4Ff0IC63sivH90vmdKcQ9n8S9Pm65g5QfZ2QKgIqSTxXxqXkd5rjuYfF8P1sW3Fu1ymitmPgUwd/p0N8nv8otMbdJe8J8sK3IQiP9GeOy7/cERHNx8Nyja20l5QCgr+IJJsyvNzWiHYHXrL4b72suVY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=s6InZzXP; arc=none smtp.client-ip=74.125.82.74 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="s6InZzXP" Received: by mail-dl1-f74.google.com with SMTP id a92af1059eb24-12bfa367189so1494710c88.0 for ; Thu, 02 Apr 2026 14:57:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1775167052; x=1775771852; darn=vger.kernel.org; h=to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=tQ3+wXp52+vINavkRYclxQ9XykPvN9/1RMTQP4wILHI=; b=s6InZzXPCztg7/FO1NJS7XcLGD20y6GgeG5IOYuLcdko7JTtgSyqAFyXVXw1wMgWZX RmxfZOIBvpAoE8fkeDZV6VSJRzRlEPcF7ERaoCsgvGuirZGpkxzleZ2eGz/khXSgmi+I KfTE7ewwzEppvNQyiIo8D93nPjvl7EKLENmNJFTn1X9FnX0jkTJY5SYrDFgclTHfZqon AJA/O+IrJA6gPiHQshIHCuPqeVynKnIDvEt5Dpg0HZO5IoxdTvYEcAqOywnCdM8bEq1c MiXmn5hvONdCQ5fhSpA+UUzNxgci53nhyfwSjDbvPHuDCQ7gsMN/nJbREieUqLmkkg0/ za9w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1775167052; x=1775771852; h=to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=tQ3+wXp52+vINavkRYclxQ9XykPvN9/1RMTQP4wILHI=; b=IZicmKkvpsWZ99O0TOZWVxt2fKI37HibqCAKOmKVIhAkSzytrO4rFWnTtu4PwSzTnM mj81GMdbV6f+BUn3EVM/wmallYt58hOd7xoE29+7tO2dymND+E8cNsvzMg4uCY1jSAhY B0FJMcdjL1iRqz32cDr0NN4PvgAJI7XDbdNfzL9lfr1ykwlOGZNsyl5xCREa3cpzXob3 xstAMulZtjtE2aCHIDW6pB8x4NpX4apurRb6p37PiwhWmnPr/xLDqVNJbxKTr14pjIxP Iw3dHTgrMJTNkQHrNVwceQcezItoU0HzhNt43DyYfzjtd3q1IWQqNowdmmhJFJQIbBRG 9Cyw== X-Forwarded-Encrypted: i=1; AJvYcCUi8nJdiBXY2RLdbzMRRRqdwTfvbl5sfEXeYNOZe5k4GKm3TkrUOXKMQHBH7M8H8aExWlvLOxugTGZT76JTONX9@vger.kernel.org X-Gm-Message-State: AOJu0YxWDez6LetYrQnvZR3laecwDME8xZ3rv3q6nPXezgkX72qS1Ryp 36YkZoNPeAmWILV+OJGLDmgiQ340dI7cWMul1Oq67H/tHggwo0tvhqFBU0V58R/bhbC7yVKLJx5 tFTurIStEnA== X-Received: from dlec15-n1.prod.google.com ([2002:a05:701b:428f:10b0:12a:c4d6:354a]) (user=irogers job=prod-delivery.src-stubby-dispatcher) by 2002:a05:7022:212:b0:11b:ec5f:1c37 with SMTP id a92af1059eb24-12bfb74468cmr361309c88.18.1775167051893; Thu, 02 Apr 2026 14:57:31 -0700 (PDT) Date: Thu, 2 Apr 2026 14:57:27 -0700 Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.53.0.1213.gd9a14994de-goog Message-ID: <20260402215727.980993-1-irogers@google.com> Subject: [PATCH v1] perf cgroup: Update metric leader in evlist__expand_cgroup From: Ian Rogers To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , James Clark , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org Content-Type: text/plain; charset="UTF-8" When the evlist is expanded the metric leader wasn't being updated. As the original evsel is deleted this creates a use-after-free in stat-shadow's prepare_metric. This was detected running the "perf stat --bpf-counters --for-each-cgroup test" with sanitizers. The change itself puts the copied evsel into the priv field (known unused because of evsel__clone use) and then in a second pass over the list updates the copied values using the priv pointer. Fixes: d1c5a0e86a4e ("perf stat: Add --for-each-cgroup option") Signed-off-by: Ian Rogers --- tools/perf/util/cgroup.c | 34 +++++++++++++++++++++++++++------- 1 file changed, 27 insertions(+), 7 deletions(-) diff --git a/tools/perf/util/cgroup.c b/tools/perf/util/cgroup.c index 040eb75f0804..1e0fef283826 100644 --- a/tools/perf/util/cgroup.c +++ b/tools/perf/util/cgroup.c @@ -417,7 +417,6 @@ static bool has_pattern_string(const char *str) int evlist__expand_cgroup(struct evlist *evlist, const char *str, bool open_cgroup) { struct evlist *orig_list, *tmp_list; - struct evsel *pos, *evsel, *leader; struct rblist orig_metric_events; struct cgroup *cgrp = NULL; struct cgroup_name *cn; @@ -452,6 +451,7 @@ int evlist__expand_cgroup(struct evlist *evlist, const char *str, bool open_cgro goto out_err; list_for_each_entry(cn, &cgroup_list, list) { + struct evsel *pos; char *name; if (!cn->used) @@ -467,21 +467,41 @@ int evlist__expand_cgroup(struct evlist *evlist, const char *str, bool open_cgro if (cgrp == NULL) continue; - leader = NULL; + /* copy the list and set to the new cgroup. */ evlist__for_each_entry(orig_list, pos) { - evsel = evsel__clone(/*dest=*/NULL, pos); + struct evsel *evsel = evsel__clone(/*dest=*/NULL, pos); + if (evsel == NULL) goto out_err; + /* stash the copy during the copying. */ + pos->priv = &evsel->core; cgroup__put(evsel->cgrp); evsel->cgrp = cgroup__get(cgrp); - if (evsel__is_group_leader(pos)) - leader = evsel; - evsel__set_leader(evsel, leader); - evlist__add(tmp_list, evsel); } + /* update leader information using stashed pointer to copy. */ + evlist__for_each_entry(orig_list, pos) { + struct evsel *evsel = pos->priv; + + if (evsel__leader(pos)) + evsel->core.leader = evsel__leader(pos)->priv; + + if (pos->metric_leader) { + evsel->metric_leader = + container_of(pos->metric_leader->priv, struct evsel, core); + } + if (pos->first_wildcard_match) { + evsel->first_wildcard_match = + container_of(pos->first_wildcard_match->priv, + struct evsel, core); + } + } + /* the stashed copy is no longer used. */ + evlist__for_each_entry(orig_list, pos) + pos->priv = NULL; + /* cgroup__new() has a refcount, release it here */ cgroup__put(cgrp); nr_cgroups++; -- 2.53.0.1213.gd9a14994de-goog