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 4E98723AB87; Tue, 13 Oct 2026 09:17:10 +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=1791883031; cv=none; b=aNxEP/Q/IGErlk/ugxQlOAdtiVeTZE9cIlJdpC6rN5eVPrftMP3dw7b/8UDgsVmdpIcT+s/k+T0h/g37MvydvYIP9oLh04WoN0cX0so5PGjKIKBa1tWXjDhKe8ihYiAO4UCVBEGQMSb7sKFz/ZySudpjDK9suivIRzz8kexJv3I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791883031; c=relaxed/simple; bh=o3hVqz2iMt7hW2IxywccrCJbpHk03oL077zjQq0SWS4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:Content-Type: MIME-Version:Message-Id; b=lvkkqTIACdAFJGfMiM9CnzCMA8PIl/rthWu77eLN4ezPu0IR19hVZQ6IK3KEmp3PfBJHmhH1zLAfmGVXra5NC0BPNIDo5FMGGs9nRMfUrTOnOy/lc6ZhlHWktyP4kex+CAG8mqLP52zDm9hKbCsUAvHauK7TxxCybASEDtKapOU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=cTTQict2; 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="cTTQict2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CE8CD1F000FF; Tue, 13 Oct 2026 09:17:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791883029; bh=xHXAoQop8Qj+PqOPWoDrnSuYWTqR2PoXrWGbU3k0ivU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=cTTQict27WBqS/1txTwjla2yFEn03enH/v+zFpy12Io25skJQb3vByl0X7mllLXs9 Xf7Szq2PAxq0ngaB258nJS09IFu7/Zuhs/vUWCJ5nCYv73xexDXUecbGnKHKJqNmNk +zMNl9y9ntpl1Ashc2OwoHfrXHfEEV7uBSr479l8dpa2jUkOQWksVQvmKjRXpMQK6D jGHJ1N4Rvae5ERJ83Fnn4ui1Nn1kIeMutUYgO8A6MYCNRQFMpk2sP/QaJmmbFNf3Ep L554P2Vscd/59xOsaMwQ7yq3ZAu7wCm6PnET37NPCIRDA/KPLY9IYL7uxVzI0IpC6W vHJ6Jkap+qDSw== From: Masami Hiramatsu (Google) To: martin@kaiser.cx Cc: Steven Rostedt , Masami Hiramatsu , Markus Schneider-Pargmann , linux-trace-kernel@vger.kernel.org, linux-kernel@vger.kernel.org, Martin Kaiser Subject: Re: [PATCH] tracing: probes: remove unused variable Date: Tue, 13 Oct 2026 09:17:07 +0000 X-Mailer: UndineD 0.1 In-Reply-To: <20260502135826.146257-1-martin@kaiser.cx> References: <20260502135826.146257-1-martin@kaiser.cx> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20261013091708.CE8CD1F000FF@smtp.kernel.org> Hi, On Sat, 02 May 2026 15:57:42 +0200, Martin Kaiser wrote: > diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c > --- a/kernel/trace/trace_probe.c > +++ b/kernel/trace/trace_probe.c > @@ -1747,7 +1746,7 @@ const char **traceprobe_expand_meta_args(int argc, const char *argv[], > if (args_idx != -1) { > /* $arg* requires BTF info */ > trace_probe_log_err(0, NOSUP_BTFARG); > + return NULL; Returning NULL here causes traceprobe_expand_meta_args() to treat this as success (no expansion needed), leaving *new_argc uninitialized and passing the unexpanded "$arg*" to subsequent argument parsing (which later fails with a confusing error). We should return an error here rather than NULL. Specifically, returning ERR_PTR(-EOPNOTSUPP) is the right fix, which also eliminates the need for the params variable. This is a bug, introduced by commit d157d7694460 ("tracing/probes: Support BTF field access from $retval"). Can you update to fix this bug? Thank you, -- Masami Hiramatsu (Google)