From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 74939C0015E for ; Fri, 11 Aug 2023 19:25:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232094AbjHKTZ3 (ORCPT ); Fri, 11 Aug 2023 15:25:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39842 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231685AbjHKTZ3 (ORCPT ); Fri, 11 Aug 2023 15:25:29 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 032F230DB; Fri, 11 Aug 2023 12:25:29 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 9005E66316; Fri, 11 Aug 2023 19:25:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 35C74C433C9; Fri, 11 Aug 2023 19:25:27 +0000 (UTC) Date: Fri, 11 Aug 2023 15:25:25 -0400 From: Steven Rostedt To: Zheng Yejian Cc: , , , Subject: Re: [PATCH] tracing: Fix race when concurrently splice_read trace_pipe Message-ID: <20230811152525.2511f8f0@gandalf.local.home> In-Reply-To: <20230810123905.1531061-1-zhengyejian1@huawei.com> References: <20230810123905.1531061-1-zhengyejian1@huawei.com> X-Mailer: Claws Mail 3.19.1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org On Thu, 10 Aug 2023 20:39:05 +0800 Zheng Yejian wrote: > When concurrently splice_read file trace_pipe and per_cpu/cpu*/trace_pipe, > there are more data being read out than expected. Honestly the real fix is to prevent that use case. We should probably have access to trace_pipe lock all the per_cpu trace_pipes too. -- Steve