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 B402132AAD6; Sun, 7 Jun 2026 23:30:38 +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=1780875040; cv=none; b=ToT7PoyWXXAAUEn/DuPE3q5amdSD9EfcRZ+C2YqYwkPqHuRnXbVLrCFSgcMMNDebm9PjsYbVj98pIQlgx3t97ZZjGWDwm/GM9yQQBdHXVwsWH5W2/qvEMijehGFwFIwBedaWtmSe4flvWkzAl9SSYz4ZLShhKKgyopiCWg/n9oM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780875040; c=relaxed/simple; bh=pztbD3iX3pd/KugXnN4XjAccZtUYB6eLIx5zr1pj1X4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=CZ6z57JjGWbVpCRuZsIxiz58yKbx/Km7R7OAJxWgEZwf8icf78dTuzSaJPh9LpUJBl0DMNRFqOmzXLVywH5IP2KbBcVQh6YfVkQp03oZB+syANZQMlhx62LzWtt0aPWG9ytvl/nRoI8IW/kybfrum95QiWv79FvNju17V+mXGqw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ou75w9xr; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ou75w9xr" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 57F581F00898; Sun, 7 Jun 2026 23:30:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780875038; bh=vJrjz18WP9YOQVzzuYUbzW7bbrjWzAs6Y8JS41ckrzw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ou75w9xrcRaZu+vfcHblcxVDahUDpQA+kd+rXQKly8h0uJjzb+8AKSN5xC7agqouY QxMFd+HGiN4g7eaoE0MtedHuUERhfFOw34QcqCnLdO70WnycjjfJdPf+GOkSAEmbEm tUUHdUklFF83jLejCFPusLamsu2UVwNnQZWkgSjNb4RchppLatIG0ldChu2D7hZ6Ca oaTwammCJPVjp7e8+tOMkoSZ7zHLsqChdzk/KQqsHwjMozYRSLYVYnQ/aX5w/6+ET/ mmIoR2+ZCWBz/9BFyAs0isa/66KgL1Tih5gGRa2M8d6BFXlbOHAkfla7uSM9armHjY hkEt7/DJHb5Qg== From: Arnaldo Carvalho de Melo To: Namhyung Kim Cc: Ingo Molnar , Thomas Gleixner , James Clark , Jiri Olsa , Ian Rogers , Adrian Hunter , Clark Williams , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Arnaldo Carvalho de Melo , sashiko-bot , "Claude Opus 4.6" Subject: [PATCH 11/11] perf tools: Use scnprintf() in build_id__snprintf() and hwmon read_events() Date: Sun, 7 Jun 2026 20:29:24 -0300 Message-ID: <20260607232925.1935819-12-acme@kernel.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260607232925.1935819-1-acme@kernel.org> References: <20260607232925.1935819-1-acme@kernel.org> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Arnaldo Carvalho de Melo build_id__snprintf() and hwmon_pmu__read_events() accumulate formatted output via snprintf(), which returns the would-have-been-written count on truncation. In build_id__snprintf(), this inflates the return value beyond the buffer size. In hwmon_pmu__read_events(), len overshoots out_buf_len and the next 'out_buf_len - len' underflows. Switch both to scnprintf() which returns actual bytes written. Fixes: fccaaf6fbbc59910 ("perf build-id: Change sprintf functions to snprintf") Fixes: 53cc0b351ec99278 ("perf hwmon_pmu: Add a tool PMU exposing events from hwmon in sysfs") Reported-by: sashiko-bot Cc: Ian Rogers Assisted-by: Claude Opus 4.6 Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/build-id.c | 2 +- tools/perf/util/hwmon_pmu.c | 12 ++++++------ 2 files changed, 7 insertions(+), 7 deletions(-) diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c index 8c0a9ae932aa5798..a3b92108f96263c6 100644 --- a/tools/perf/util/build-id.c +++ b/tools/perf/util/build-id.c @@ -94,7 +94,7 @@ int build_id__snprintf(const struct build_id *build_id, char *bf, size_t bf_size } for (size_t i = 0; i < build_id->size && offs < bf_size; ++i) - offs += snprintf(bf + offs, bf_size - offs, "%02x", build_id->data[i]); + offs += scnprintf(bf + offs, bf_size - offs, "%02x", build_id->data[i]); return offs; } diff --git a/tools/perf/util/hwmon_pmu.c b/tools/perf/util/hwmon_pmu.c index fb3ffa8d32ad2a93..dbf6a71af47f9a42 100644 --- a/tools/perf/util/hwmon_pmu.c +++ b/tools/perf/util/hwmon_pmu.c @@ -442,12 +442,12 @@ static size_t hwmon_pmu__describe_items(struct hwmon_pmu *hwm, char *out_buf, si buf[read_len] = '\0'; val = strtoll(buf, /*endptr=*/NULL, 10); - len += snprintf(out_buf + len, out_buf_len - len, "%s%s%s=%g%s", - len == 0 ? " " : ", ", - hwmon_item_strs[bit], - is_alarm ? "_alarm" : "", - (double)val / 1000.0, - hwmon_units[key.type]); + len += scnprintf(out_buf + len, out_buf_len - len, "%s%s%s=%g%s", + len == 0 ? " " : ", ", + hwmon_item_strs[bit], + is_alarm ? "_alarm" : "", + (double)val / 1000.0, + hwmon_units[key.type]); } close(fd); } -- 2.54.0