From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f202.google.com (mail-pg1-f202.google.com [209.85.215.202]) (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 BD03D2DC339 for ; Wed, 3 Dec 2025 21:47:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764798436; cv=none; b=LdSl414feRpFXLNZGWE55ghbQdqChKNc1yDBAaT/5IXgkEYawvdyYbbn3NdT504nNqlABWjtD7tX0ZBrLYoGzETs3TZcQUaAVgx20PQQAY5AJJBhvZ9uNUFMvO9X1p5jVW08BbVX+VY5UDZNqv9Nqw3LB/9xiICPbO/kniBRmmI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764798436; c=relaxed/simple; bh=RnRkqXZ4JTrwCm2Wz2Zuk8jh3jbWrplurAPzXjoLNRs=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=mawQIRLZGf6CuTbhw7pxHgvh808YKbpkCLFyysWys4Y9DOEvBIaiderGw3S8t7AYM30Ys9NymaGIqixxJo4Uj3krJpGx2yOWHt119vW/8y4Hogbk4LiEYxQaaGjQvg/2GqVDz1c4n7QGS1NhvupClFD3Q62UGTZvaFL2TzssZrQ= 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=B2OugdYP; arc=none smtp.client-ip=209.85.215.202 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="B2OugdYP" Received: by mail-pg1-f202.google.com with SMTP id 41be03b00d2f7-bce224720d8so323005a12.1 for ; Wed, 03 Dec 2025 13:47:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1764798434; x=1765403234; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=eOcSMNeJ/ZMXLpzeMBUmAqAigtJI1TPFFdhHf8jwosU=; b=B2OugdYPk/CQs+p3NCdKT+0vV5ZMaghUiPdabUb+M2wBGuTnmSo7R1z8SzAQJ0B41Z iN50Hxh2FebPyudNLMp9NAYuL0IHoxYwj55lSlWp5wzR9zYzxZy7bUzeaaZqjn45N5MS BBeVQQSgL/CWjxC5doLFS3PBT/QeW6+6BvWeO6P1+EmafzxbXPkiip85/quby+9h/QFQ XAJGJMLrVYvRM5/Ye97hSLGSAopG4r9KHvccWPjAAxXi18ln4XPAUT0Llme8QDZy+m/i Rx3atFvrX+ptxVDdsKC7b2BsBYtPTVNUJKMdppSCjoL/0fXIYxIMNLLYjA6jWjQxTCV0 KFxA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1764798434; x=1765403234; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=eOcSMNeJ/ZMXLpzeMBUmAqAigtJI1TPFFdhHf8jwosU=; b=PHFs5C0f5OPrg8+q6LJYA5WEj6cHrzqADQzDElPlxlCQyz06rtORUjBmLvFU+9WNI6 89KVCKFMrBubF+xFXOpjLrhBwpaCynsWST79odccyrRZ2sUvqlWJtOgqBKbdorSKQMsN v9X7lh5xy9HoIy0LNl+hEEY4HRr1aCEn2sd9FnfZtmDzuggU/0HCfN74puLOOXRuFoGl b7c/wjQwno8HAAQfwQ48NSQ83Klb1UoPymlgECvfrRWncLD2BCsEcuQqwRJk3EztAeCj 6wMRoDjqI3DBRSQgxuuG3OwuxkUDA8wEYz8bGoq83I53lZSNWkKPWJeIBZt0efXHDV5J 3EfA== X-Forwarded-Encrypted: i=1; AJvYcCUx2fV7HSR2kHpy0SXMJ1IVCPmKFpVRrjGaAXVnCgfaSXbrhc3vZK9Ulbp1xAQtpM8mY90ngnADB36CgyL+pYF3@vger.kernel.org X-Gm-Message-State: AOJu0YzGX8VGHYCYNsAMHEXxIl4vIWRl0a5Re/SyUBXTPi+HpCMn3Stz V8z6jDFZiu0+2j5sqy7XZb8H+Y5LTBySj4lo+HKutG1HtmsnMLO0LrjrMyDxNyWbB3JrbAEd23k lGSxLVsO4mw== X-Google-Smtp-Source: AGHT+IFm5eUCWRwz5Nfygqjtwh5PieLN6MVOHBcL6m3z8SCNLQ9bZBKQIdp75woC2gQZxpW8S+MHehpUntax X-Received: from dyjn15.prod.google.com ([2002:a05:7300:a8f:b0:2a4:5a4a:cc6d]) (user=irogers job=prod-delivery.src-stubby-dispatcher) by 2002:a05:7301:b0a:b0:2a6:d0bd:4a07 with SMTP id 5a478bee46e88-2ab92e52960mr1991364eec.18.1764798433998; Wed, 03 Dec 2025 13:47:13 -0800 (PST) Date: Wed, 3 Dec 2025 13:47:01 -0800 In-Reply-To: <20251203214706.112174-1-irogers@google.com> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20251203214706.112174-1-irogers@google.com> X-Mailer: git-send-email 2.52.0.177.g9f829587af-goog Message-ID: <20251203214706.112174-3-irogers@google.com> Subject: [PATCH v2 2/7] libperf cpumap: Fix perf_cpu_map__max for an empty/NULL map From: Ian Rogers To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , James Clark , Thomas Richter , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Ingo Molnar Content-Type: text/plain; charset="UTF-8" Passing an empty map to perf_cpu_map__max triggered a SEGV. Explicitly test for the empty map. Reported-by: Ingo Molnar Closes: https://lore.kernel.org/linux-perf-users/aSwt7yzFjVJCEmVp@gmail.com/ Tested-by: Ingo Molnar Signed-off-by: Ian Rogers --- tools/lib/perf/cpumap.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/tools/lib/perf/cpumap.c b/tools/lib/perf/cpumap.c index 7e88417ba84d..4160e7d2e120 100644 --- a/tools/lib/perf/cpumap.c +++ b/tools/lib/perf/cpumap.c @@ -368,10 +368,12 @@ struct perf_cpu perf_cpu_map__max(const struct perf_cpu_map *map) .cpu = -1 }; - // cpu_map__trim_new() qsort()s it, cpu_map__default_new() sorts it as well. - return __perf_cpu_map__nr(map) > 0 - ? __perf_cpu_map__cpu(map, __perf_cpu_map__nr(map) - 1) - : result; + if (!map) + return result; + + // The CPUs are always sorted and nr is always > 0 as 0 length map is + // encoded as NULL. + return __perf_cpu_map__cpu(map, __perf_cpu_map__nr(map) - 1); } /** Is 'b' a subset of 'a'. */ -- 2.52.0.177.g9f829587af-goog