From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 8A9E13DBD5E; Tue, 24 Mar 2026 15:42:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774366962; cv=none; b=iAM0soZxOSZAo/t6JVKnNXJ8wPWQgbcMPRQBBu3K90bBan1uK8Ne55yWDmR/8vrOhOD0Y5SG5fE2Ta9L7gBggSsrrWR4aQP0bdqyK5AUp1F23Ek+BuB9G6bxI8F2YAvCVZelxv7T25WqZ4AngiH3vx8twXCwMDbdLW2Z18wx2Ro= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774366962; c=relaxed/simple; bh=2Zsq8skSNnh/MXXGZNOJx5noaTfOOayvR6/+7n/9yQk=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=u950vr2ePy6zQuLJdeJN6Fz83Tv8q+Taiq7qegNaYES1j659qYsGQMkdU84HlOJdV42pyvHvzF9P1JBChwVOFmT2kn/TolH35OePuITmzaqhlDXObUobDf+sBVisdpHwOKg2+RbAVBrEtKizTOEPVm2qyN4u2ah1c6R40Sqw3Q4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Xt9xEVjR; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Xt9xEVjR" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 74097C19424; Tue, 24 Mar 2026 15:42:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774366962; bh=2Zsq8skSNnh/MXXGZNOJx5noaTfOOayvR6/+7n/9yQk=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Xt9xEVjRQAy03h/xT4dHGrNbiSNtzplkl0cuifiVSX409f/6fyMyTsESXCWptScD7 dWGIsldm2WS6Y6M5mMzZEj3TJq39ggbLB9YmlDcjM1di0nAOPfW8l7wljVsFc0kFpA Ns+XDCwYvUlXgbTO1x56OqzDWZpY6dS2GZVHZ/KeN23X9fGwJUOupUfgKUvIdwdmiS jCTJqPO23SMvRjyAXYRhjp6TyFNZrrj3NCPslpKDtJGhS8tMA5onHfpl1aEJIBXGDs sFlVF1eXuVojai4DCy6LrUMFoqgspCVtQKU8OQv3KEcc1nQcr8QPi+QqeOVVhe+GFm drptW/zYQ89wg== Date: Wed, 25 Mar 2026 00:42:38 +0900 From: Masami Hiramatsu (Google) To: Steven Rostedt Cc: Martin Kaiser , Masami Hiramatsu , Mathieu Desnoyers , linux-trace-kernel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] tracing: fprobe: do not zero out unused fgraph_data Message-Id: <20260325004238.a25e7dc93f891d4cf17f76aa@kernel.org> In-Reply-To: <20260324083903.414352aa@gandalf.local.home> References: <20260323102020.239567-1-martin@kaiser.cx> <20260324084804.375764-1-martin@kaiser.cx> <20260324083903.414352aa@gandalf.local.home> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) 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=US-ASCII Content-Transfer-Encoding: 7bit On Tue, 24 Mar 2026 08:39:03 -0400 Steven Rostedt wrote: > On Tue, 24 Mar 2026 09:47:08 +0100 > Martin Kaiser wrote: > > Hi Martin, > > First, please do not send a v2 as a reply to v1. A new version should > always start a new mail thread. > > > If fprobe_entry does not fill the allocated fgraph_data completely, the > > unused part does not have to be zeroed. > > > > fgraph_data is a short-lived part of the shadow stack. The preceding > > length field allows locating the end regardless of the content. > > > > Signed-off-by: Martin Kaiser > > --- > > v2: > > But to maintain a link to the previous version, I recommend adding here: > > Changes since v1: https://lore.kernel.org/all/20260324084804.375764-1-martin@kaiser.cx Ah, this is a good idea for the patch which does not have cover mail. Thanks :) > > > > - remove the memset instead of fixing the length > > > > kernel/trace/fprobe.c | 2 -- > > 1 file changed, 2 deletions(-) > > > > diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c > > index dcadf1d23b8a..56d145017902 100644 > > --- a/kernel/trace/fprobe.c > > +++ b/kernel/trace/fprobe.c > > @@ -450,8 +450,6 @@ static int fprobe_fgraph_entry(struct ftrace_graph_ent *trace, struct fgraph_ops > > used += FPROBE_HEADER_SIZE_IN_LONG + size_words; > > } > > } > > - if (used < reserved_words) > > - memset(fgraph_data + used, 0, reserved_words - used); > > > > /* If any exit_handler is set, data must be used. */ > > return used != 0; > > As for the patch, > > Reviewed-by: Steven Rostedt (Google) > > -- Steve > -- Masami Hiramatsu (Google)