From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 285AA3B1EFC; Tue, 21 Jul 2026 20:38:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784666323; cv=none; b=Czo7sFcqJGJg35UyBvc70BvUsEkgtI1irs/oGtDXWQmtVZCnDr5Dxvq4VA5LPYHQTWEH3RLnSqJlXp0ZvQXKMNygEO8R4I7dNcAbmyJv78kNrAMAytKM/WrK1yxoKU6vuyjjY+Y2qrP8wkjnztG4Q20WuGaJrc84buaN8BYa3AI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784666323; c=relaxed/simple; bh=lfdGjObl9EdyrG2IrRbk8J7x/tOLqXtdNb7Gz4EhU+A=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=up39M38IPbaBabmaMCfaCoIYY6A7Ns1Pzz9jmKH1OeQWhlBEEezB4IEq1epUSZtbvg/R0GxBnAq05YsQx1FqWb7uQwT3mzIDtGDFtnWXAVvcnjleg1PddSUhFssh2ot8gh03pREHvPMt8scQOtis+k5lSIOvRY5Y+a4adueFoYc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=WaaxlgeB; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="WaaxlgeB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 68D4C1F000E9; Tue, 21 Jul 2026 20:38:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784666321; bh=RC2/kb1Zu3Xv3dRRtAIGXN8+XtvwMYYScv60wcUCMvM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=WaaxlgeB5Cj33tQg345swmEMHt0vEfGCvG8DM+J6Bu82of39sdw+lbpvlbcXtM7E2 L1e256iP8dCugj15fcja92nI6KtS71+DBLHTKxXcOkl//fWWccfVB3OT62enkJIgNt Lt2VdjjsixAlk5B8rJQepGcLxmh77rUfQPeFbc0E= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Ian Rogers , Arnaldo Carvalho de Melo , Sasha Levin , sashiko-bot@kernel.org Subject: [PATCH 6.6 0637/1266] perf sched: Replace BUG_ON on invalid CPU with graceful skip Date: Tue, 21 Jul 2026 17:17:54 +0200 Message-ID: <20260721152456.109948111@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152441.786066624@linuxfoundation.org> References: <20260721152441.786066624@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Arnaldo Carvalho de Melo [ Upstream commit 1e2c83f732deb329ebce23e26cbc482f4c4bf194 ] latency_switch_event(), latency_runtime_event(), and map_switch_event() use BUG_ON(cpu >= MAX_CPUS || cpu < 0) to validate the sample CPU. When PERF_SAMPLE_CPU is absent from the sample type, evsel__parse_sample() initializes sample->cpu to (u32)-1. Casting this to int yields -1, which triggers the BUG_ON and aborts perf sched. The central CPU validation in perf_session__deliver_event() intentionally preserves the (u32)-1 sentinel for downstream tools like perf script and perf inject, so leaf callbacks must handle it themselves. Replace the three BUG_ON calls with graceful skips using pr_warning(), matching the existing pattern in process_sched_switch_event() and process_sched_runtime_event() earlier in the same file. Include the file offset for cross-referencing with perf report -D. Reported-by: sashiko-bot@kernel.org # Running on a local machine Reviewed-by: Ian Rogers Assisted-by: Claude:claude-opus-4.6 Signed-off-by: Arnaldo Carvalho de Melo Stable-dep-of: 8cbca8a480e1 ("perf sched: Fix NULL dereference in latency_runtime_event") Signed-off-by: Sasha Levin --- tools/perf/builtin-sched.c | 22 +++++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-) diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c index 942fde8a1d52e3..9e9bb19f0bc98b 100644 --- a/tools/perf/builtin-sched.c +++ b/tools/perf/builtin-sched.c @@ -1154,7 +1154,12 @@ static int latency_switch_event(struct perf_sched *sched, int cpu = sample->cpu, err = -1; s64 delta; - BUG_ON(cpu >= MAX_CPUS || cpu < 0); + /* perf.data is untrusted input — CPU may be absent or corrupted */ + if (cpu >= MAX_CPUS || cpu < 0) { + pr_warning("WARNING: at offset %#" PRIx64 ": out-of-bound sample CPU %d, skipping sample\n", + sample->file_offset, cpu); + return 0; + } timestamp0 = sched->cpu_last_switched[cpu]; sched->cpu_last_switched[cpu] = timestamp; @@ -1225,7 +1230,13 @@ static int latency_runtime_event(struct perf_sched *sched, if (thread == NULL) return -1; - BUG_ON(cpu >= MAX_CPUS || cpu < 0); + /* perf.data is untrusted input — CPU may be absent or corrupted */ + if (cpu >= MAX_CPUS || cpu < 0) { + pr_warning("WARNING: at offset %#" PRIx64 ": out-of-bound sample CPU %d, skipping sample\n", + sample->file_offset, cpu); + err = 0; + goto out_put; + } if (!atoms) { if (thread_atoms_insert(sched, thread)) goto out_put; @@ -1596,7 +1607,12 @@ static int map_switch_event(struct perf_sched *sched, struct evsel *evsel, const char *color = PERF_COLOR_NORMAL; char stimestamp[32]; - BUG_ON(this_cpu.cpu >= MAX_CPUS || this_cpu.cpu < 0); + /* perf.data is untrusted input — CPU may be absent or corrupted */ + if (this_cpu.cpu >= MAX_CPUS || this_cpu.cpu < 0) { + pr_warning("WARNING: at offset %#" PRIx64 ": out-of-bound sample CPU %d, skipping sample\n", + sample->file_offset, this_cpu.cpu); + return 0; + } if (this_cpu.cpu > sched->max_cpu.cpu) sched->max_cpu = this_cpu; -- 2.53.0