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 949193F7ABD; Tue, 24 Mar 2026 15:40:56 +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=1774366856; cv=none; b=IvqdX+j/yUELRiEvGhRL0tZp+QuW0Ugeikwp3lNWnJoDppibNesuQONul2+39X6E50xLzvlAYmayfw/+GS0DuiRKARuO3TrBqvdLP5tlzeQd9vHEzKQ3FWeQ5L1AUf1qwVEAvr4JAhQy6yVYJzhoydYkO9xmb0tdSMdNHn7Fk+o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774366856; c=relaxed/simple; bh=jWFuQ3Kdo1D0JtKs3AolKcKwxPfsEtZJqWSbcU608hE=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=Yk4J2+yb7VqTVVsPPCOpl39BzKs7Sg76QT8iP1DfTTgmnIhI6ylneU4AIRDmr+SFgC2rSDdob/41h5k0OCThxIoMp1EAfVwV82dUaShyMWsE2lGLpM70WQSyxmsxBdgmTh2wDwtkUnjf9Mr0I5RRU1N+K1iCnkQL4QEfNJBr988= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gz27DkUe; 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="gz27DkUe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 71B04C19424; Tue, 24 Mar 2026 15:40:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774366856; bh=jWFuQ3Kdo1D0JtKs3AolKcKwxPfsEtZJqWSbcU608hE=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=gz27DkUeBt4CJlk0LdOCTfmZicUy+pCcH95s+Cee0mhqg67sIhlIqTt8F51bLBnCB k/LaWJnCzT+N6tyJkcUNO0fXb3P7oJFsVVxHJyLbQ/7fODylz+p6aUWTLVD+1gJxX5 Wv1JChAVZ4OGvlDRTiO+mhReJTsOahWmDVuVcrRJMpTfBEoXHlonhuik8NVsNuDCD/ no6vvhkVRmz8cQF9Ez96gCNkB8Bo4wXo3pGMWN1jIXN3AwNuoMsg4WhLBj0x9/dtmt WeqP0AVYXNGMWiO3EeOiS4zb5DhLIOdiwdGpt7iU5k1VNEtzJj6s7nKPUZvANYNI3B +pAefur/kvxEA== Date: Wed, 25 Mar 2026 00:40:52 +0900 From: Masami Hiramatsu (Google) To: Martin Kaiser Cc: Steven Rostedt , 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: <20260325004052.6f6629965addb617728eac92@kernel.org> In-Reply-To: <20260324084804.375764-1-martin@kaiser.cx> References: <20260323102020.239567-1-martin@kaiser.cx> <20260324084804.375764-1-martin@kaiser.cx> 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 09:47:08 +0100 Martin Kaiser wrote: > 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 OK, thanks for update. Let me pick it. Thanks, > --- > v2: > - 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; > -- > 2.43.7 > -- Masami Hiramatsu (Google)