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 119C7221F1C for ; Wed, 19 Nov 2025 05:06:04 +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=1763528767; cv=none; b=mzt+lxYs2DZGvWnTbIHuXFsmQ5clEi39hgw7xhTmTG9n5Vm8kzqWVGj/jd7PVZaE1jhpgGh8oV+gtotb+zfePTkCI0hczINCwrGj4wa5Nyv279NImrgEsQtYNNpgiGZovZ13k3SAdHnH/ZUmuLaIRaNEUtjPL9IrhEBHuI7rg4M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763528767; c=relaxed/simple; bh=AL35jIWqLpEQrobs8WzgN+Or4eupxZTkrsxCfQu3Gek=; h=Date:Mime-Version:Message-ID:Subject:From:To:Content-Type; b=cy2phn5hxHgzVIvh2LseGECXpPSVOGER3Z16oeLVY+te759lYBfSm3t8E9pabn8zZGp8p5GOrRQb5NvzgsJd/8sQPTREkygdwFTjuyiVenQ3/7plz9kG7T46w5LGLCAYULSkv7jUTbrzGo5o9041I09kzSLrth8pqc5bl6IFIeA= 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=Ztrg9DOK; 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="Ztrg9DOK" Received: by mail-pg1-f202.google.com with SMTP id 41be03b00d2f7-b55735710f0so11289063a12.2 for ; Tue, 18 Nov 2025 21:06:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1763528764; x=1764133564; darn=vger.kernel.org; h=to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=c4Sj77sHnV/MC5K9XeYJi0BLwRXY/iWwwqmvNrD5ZVY=; b=Ztrg9DOKew/ZDl5W0wN4eZ9aDk2nzNEJ84+Ht6McX2gstJrJYSv4N4hhtw/wLRuWLZ C5qqEq2WP3ntgjp9S4HIVJJT3lNYMWd+/4NAVpbp5jTHkjl9u+3SXr0akZYrCUyaU/3p xV22LFjikK+YIPaY+UDxKCSvnCvO0nlAKj9uo/xrwfYyFWjzKp98Gw/ucHmKZTRFWEJL FVX/X9kvuu3pn9sehrEJ7vSFE+co7PGcVqAWWk7VFmn+O+C7zabSOBqzmC+TapY3Xvg+ +ReTRR4wiy3ux2+Iauj7wlP6uRDoOhv/BzpreJkeI07uLSRHwyYTzdQm8h8yIclNlWTg pWNw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1763528764; x=1764133564; h=to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=c4Sj77sHnV/MC5K9XeYJi0BLwRXY/iWwwqmvNrD5ZVY=; b=sQS3UQHIASmWh+zcmxgbFD63qGxai8Du8O3Djf0PH5ifvAUOybdyojP8YS/yQ4o7ab Bo9/sYSuM9H1AoYtyC4ltzmmo4/PdWTChoJd/OhjNMVTzD566cVU7WCZcGugyCOtbD9r JyygwIAeYGbjAANqmb/4tGMnv276htaQTFLOtjQiyuDioV7Ni4Pwc8XtWdE1LoMJfcGh He7qvz5IhJZnZGmXHUhjzBsWsSWzslqBZnyfNq16FDg2PHO+CKPC7/pSqR6io1Gh7LIG EYKnFL+0Ya+dpjOAgvrDmMxQufdhtLu5BsqqFl4wmLgF5GYCw+aMjJNDLiXe5oOoMviI e0Ow== X-Forwarded-Encrypted: i=1; AJvYcCVD7QJisxOAXy2bPYe/QTkf0jKOQw18jBy95AMafX5g4zpRekDQmwdSzfTQKZkZGBD5lnnwZxVMAUjW9UY=@vger.kernel.org X-Gm-Message-State: AOJu0Yxv6SdsTJ6FtvuU4Uw5lcJYS2FRSu4EIuqzRbVuWZSxEpOsJP74 3bbyhAos821I1NExlI/EALfFDPShypGNTPe83UXStOulPDrIWafiz0QHRyzu1U4lOlWiCwmlzNA rTotKbLzR9w== X-Google-Smtp-Source: AGHT+IGSBE0RhBdd+d35qnzp5bKWP7QhMELtgQ6Z0RKPQAoNRniyHdZX2nUfVBbobHicgrQi/mmYWei/QZOu X-Received: from dybic37.prod.google.com ([2002:a05:7300:c725:b0:2a4:603a:d428]) (user=irogers job=prod-delivery.src-stubby-dispatcher) by 2002:a05:7300:d50b:b0:2a4:617a:419f with SMTP id 5a478bee46e88-2a4aba98c9amr9258681eec.2.1763528764050; Tue, 18 Nov 2025 21:06:04 -0800 (PST) Date: Tue, 18 Nov 2025 21:05:54 -0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.52.0.rc1.455.g30608eb744-goog Message-ID: <20251119050555.2017758-1-irogers@google.com> Subject: [PATCH v1 1/2] perf maps: Avoid RC_CHK use after free From: Ian Rogers To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , James Clark , German Gomez , Ravi Bangoria , Christophe Leroy , Chun-Tse Shao , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, kernel test robot Content-Type: text/plain; charset="UTF-8" The case of __maps__fixup_overlap_and_insert where the "new" maps covers existing mappings can create a use-after-free with reference count checking enabled. The issue is that "pos" holds a map pointer from maps_by_address that is put from maps_by_address but then used to look for a map in maps_by_name (the compared map is now a use-after-free). The issue stems from using maps__remove which redoes some of the searches already done by __maps__fixup_overlap_and_insert, so optimize the code (by avoiding repeated searches) and avoid the use-after-free by inlining the appropriate removal code. Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-lkp/202511141407.f9edcfa6-lkp@intel.com Signed-off-by: Ian Rogers --- tools/perf/util/maps.c | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-) diff --git a/tools/perf/util/maps.c b/tools/perf/util/maps.c index 779f6230130a..c321d4f4d846 100644 --- a/tools/perf/util/maps.c +++ b/tools/perf/util/maps.c @@ -931,8 +931,9 @@ static int __maps__fixup_overlap_and_insert(struct maps *maps, struct map *new) return err; } else { struct map *next = NULL; + unsigned int nr_maps = maps__nr_maps(maps); - if (i + 1 < maps__nr_maps(maps)) + if (i + 1 < nr_maps) next = maps_by_address[i + 1]; if (!next || map__start(next) >= map__end(new)) { @@ -953,7 +954,24 @@ static int __maps__fixup_overlap_and_insert(struct maps *maps, struct map *new) check_invariants(maps); return err; } - __maps__remove(maps, pos); + /* + * pos fully covers the previous mapping so remove + * it. The following is an inlined version of + * maps__remove that reuses the already computed + * indices. + */ + map__put(maps_by_address[i]); + memmove(&maps_by_address[i], + &maps_by_address[i + 1], + (nr_maps - i - 1) * sizeof(*maps_by_address)); + + if (maps_by_name) { + map__put(maps_by_name[ni]); + memmove(&maps_by_name[ni], + &maps_by_name[ni + 1], + (nr_maps - ni - 1) * sizeof(*maps_by_name)); + } + --RC_CHK_ACCESS(maps)->nr_maps; check_invariants(maps); /* * Maps are ordered but no need to increase `i` as the -- 2.52.0.rc1.455.g30608eb744-goog