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 D54263E0749; Mon, 20 Jul 2026 10:12:35 +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=1784542369; cv=none; b=hsfBHCCVgDc/Id8y5cA0Wr05Mq/6C6xl1eDh+8zeyQdP6qeKUMtAfv2Uhi2Pbtw/eTHFER2hBHNR5n0Z4n/k/wAMLrubTcBhDnEDzGDcPHhKnhS3e6GFRCeNE4JIYsSyAKr7Eo8nlpvXishWUq7YEqkyYGAV03/7TmoSVoQYgHg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784542369; c=relaxed/simple; bh=wDNlZX4N0mTjaVYhKlMTx430kPWvfP4V810QBypJb5w=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Xfv+VHaX+5v1FGF6Q701gr45KmrAYu+m0pRgF1o6ECQzbpCGdTocwfkrutT+3aFzRoGb9u7KCNUeTZYhURMROPxb8vhEBsFy/9UMNhcG6YWKxz40uKms3l0OB2ZJCa02Ps0mbkX5+aiUTltknl25vaKxMBytV/maW/jU4QpvbAM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jGOrxmMy; 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="jGOrxmMy" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BED891F00A3A; Mon, 20 Jul 2026 10:12:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784542353; bh=PJy2QJ5d4MMnuzXMiWK9VOTWPQHlURmP4d7ABbZpQ74=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=jGOrxmMyM3YTX2Yit9aVnqcgTkbiyeZ5qDP0hX7JrostQVAKDyW14bEkQs1b7Dwwi 8ukob3pbUEF3cKwK7dLPCzu2u78Xoi0J348ZfOlUI9/hLzwQE3eLmxYF+6Sn72tn/d FfIHzDKHdCy3skXBOf5U+35dTCKylzeVHOZ+erXN4fEpsJtKFjl2trguUQHPYcFGpY 0PUfU7J0ZM4nQ05BL3RpXutsQK14kUQW42OB3AGQttU3edTzXpCyZ2ujr0t1cGawYP ejTJBWIaEDcuJmt0Sdq0yVbsaEa01+6RuRXrDeP3KyM9LJDSKur/OjsOQw8sC/QO3p gioX0ywv7HlIQ== From: "Masami Hiramatsu (Google)" To: Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: [PATCH 3/4] tracing/probes: Fix potential underflow in LEN_OR_ZERO macro Date: Mon, 20 Jul 2026 19:12:29 +0900 Message-ID: <178454234934.290363.15247317871499514139.stgit@devnote2> X-Mailer: git-send-email 2.43.0 In-Reply-To: <178454232006.290363.11301475407231432622.stgit@devnote2> References: <178454232006.290363.11301475407231432622.stgit@devnote2> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit From: Masami Hiramatsu (Google) In __set_print_fmt(), LEN_OR_ZERO is defined as (len ? len - pos : 0). If len is non-zero but smaller than pos, len - pos evaluates to a negative integer. When passed as a size argument to snprintf(), this negative value is cast to a large unsigned size_t, bypassing buffer size limits. Ensure len > pos before subtracting to avoid integer underflow. Fixes: 5bf652aaf46c ("tracing/probes: Integrate duplicate set_print_fmt()") Cc: stable@vger.kernel.org Assisted-by: Antigravity:gemini-3.5-flash Signed-off-by: Masami Hiramatsu (Google) --- kernel/trace/trace_probe.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c index 49daa3cc2a45..506e6037e163 100644 --- a/kernel/trace/trace_probe.c +++ b/kernel/trace/trace_probe.c @@ -2013,7 +2013,7 @@ int traceprobe_update_arg(struct probe_arg *arg) } /* When len=0, we just calculate the needed length */ -#define LEN_OR_ZERO (len ? len - pos : 0) +#define LEN_OR_ZERO (len > pos ? len - pos : 0) static int __set_print_fmt(struct trace_probe *tp, char *buf, int len, enum probe_print_type ptype) {