From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from dggsgout12.his.huawei.com (dggsgout12.his.huawei.com [45.249.212.56]) (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 BB7DF7261E; Fri, 22 Aug 2025 01:35:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755826549; cv=none; b=ARCcjije5bt924QK4FpQhOARd0gall4ta5jVCjp4WmQy66oLrGKiFxmsT+AbpMm1ybdJ4vdxtVSEPj5kIi1hKdt/eWC1cVvcXT37emIog/YZf3Cxc3GGGHU4zrvTc+u52fnwqqSp4mfgEy68kruMhzUN8ER7bJ2KHCx78nWRw9Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755826549; c=relaxed/simple; bh=JalOgAPy+10ijoEjkUyxw2IZaQ73SnV+0ZOBdc0KXz4=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=qgk6jV3Rs7jkhFCMVfCwZbXTi2Iingslmz9QcnIdIlnuLTdXEUYMNnNEZa8msZuwXUqSQR7o7cwvx9MeRZs5fMbl0M7zHg+uE/LsBcQLHSVtwkeHdULX6a8CB5KnGgGzNd1x/FHUyS6JwZNXHoBDx6zUi18vDNCYzKKHhgbUAEI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com; spf=pass smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.163.216]) by dggsgout12.his.huawei.com (SkyGuard) with ESMTPS id 4c7N746wB9zKHMww; Fri, 22 Aug 2025 09:35:44 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.128]) by mail.maildlp.com (Postfix) with ESMTP id 763841A1724; Fri, 22 Aug 2025 09:35:44 +0800 (CST) Received: from [10.67.110.36] (unknown [10.67.110.36]) by APP4 (Coremail) with SMTP id gCh0CgAX3w9vyadomKT9EQ--.7615S2; Fri, 22 Aug 2025 09:35:44 +0800 (CST) Message-ID: Date: Fri, 22 Aug 2025 09:35:43 +0800 Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH -next] ftrace: Fix potential warning in trace_printk_seq during ftrace_dump To: Steven Rostedt Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Ingo Molnar , linux-trace-kernel@vger.kernel.org, linux-kernel@vger.kernel.org References: <20250820090017.2978279-1-wutengda@huaweicloud.com> <20250820101054.50c0b8b8@gandalf.local.home> <40bcf20b-e2e6-442f-bfd8-bb7ad6245397@huaweicloud.com> <20250821105113.1536d567@gandalf.local.home> Content-Language: en-US From: Tengda Wu In-Reply-To: <20250821105113.1536d567@gandalf.local.home> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CM-TRANSID:gCh0CgAX3w9vyadomKT9EQ--.7615S2 X-Coremail-Antispam: 1UD129KBjDUn29KB7ZKAUJUUUUU529EdanIXcx71UUUUU7v73 VFW2AGmfu7bjvjm3AaLaJ3UjIYCTnIWjp_UUUYb7kC6x804xWl14x267AKxVW8JVW5JwAF c2x0x2IEx4CE42xK8VAvwI8IcIk0rVWrJVCq3wAFIxvE14AKwVWUJVWUGwA2ocxC64kIII 0Yj41l84x0c7CEw4AK67xGY2AK021l84ACjcxK6xIIjxv20xvE14v26w1j6s0DM28EF7xv wVC0I7IYx2IY6xkF7I0E14v26r4UJVWxJr1l84ACjcxK6I8E87Iv67AKxVW0oVCq3wA2z4 x0Y4vEx4A2jsIEc7CjxVAFwI0_GcCE3s1le2I262IYc4CY6c8Ij28IcVAaY2xG8wAqx4xG 64xvF2IEw4CE5I8CrVC2j2WlYx0E2Ix0cI8IcVAFwI0_JrI_JrylYx0Ex4A2jsIE14v26r 1j6r4UMcvjeVCFs4IE7xkEbVWUJVW8JwACjcxG0xvEwIxGrwCF04k20xvY0x0EwIxGrwCF 54CYxVCY1x0262kKe7AKxVWUAVWUtwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F4 0E14v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_JF0_Jw1l IxkGc2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxV AFwI0_Gr0_Cr1lIxAIcVCF04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r1j 6r4UMIIF0xvEx4A2jsIEc7CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x07UQzV bUUUUU= X-CM-SenderInfo: pzxwv0hjgdqx5xdzvxpfor3voofrz/ On 2025/8/21 22:51, Steven Rostedt wrote: > On Thu, 21 Aug 2025 09:53:53 +0800 > Tengda Wu wrote: > >> There remains an edge case that concerns me: if size is 0, setting len to >> size - 1 would cause an underflow. Should we handle this edge case? > > When the trace_seq is allocated, the size is set to 8K. If size is ever > zero, then there would be no buffer. So no, we should not worry about that > edge case because if it happened then we have a lot of other things to > worry about. > > -- Steve Got it, thanks for the clarification. -- Tengda