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 X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 41632C2D0EF for ; Sat, 18 Apr 2020 10:40:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1F2E121D79 for ; Sat, 18 Apr 2020 10:40:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587206405; bh=iYctGlzbmQKCrnj8Y/ccy/38iw5U0if3D+PjnXv00tA=; h=Subject:To:Cc:From:Date:List-ID:From; b=IyDM3MHRRGbExhP8ltpWHtiNSdsfQRkBTzyD9FyLc1zLSbEqUpCpTbYQFif+cghIV tqPvH2be5xddIEVa9LiBZ6IhNzO5cDk0D15YXiHDjO1HJDFt2BxZDbmg4yYIAY0o+8 xbyNp6RCG0E97oooHVZaMsqpFpd5Onagbbn2iBh0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725857AbgDRKkE (ORCPT ); Sat, 18 Apr 2020 06:40:04 -0400 Received: from wforward5-smtp.messagingengine.com ([64.147.123.35]:50995 "EHLO wforward5-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725799AbgDRKkE (ORCPT ); Sat, 18 Apr 2020 06:40:04 -0400 Received: from compute1.internal (compute1.nyi.internal [10.202.2.41]) by mailforward.west.internal (Postfix) with ESMTP id A32C34B0; Sat, 18 Apr 2020 06:40:03 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute1.internal (MEProxy); Sat, 18 Apr 2020 06:40:03 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:content-type :date:from:message-id:mime-version:subject:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm2; bh=JGNrP4 KBlYxxLHJDW0caKRkyfV6+OBxazJPcl6KKjF4=; b=lnoQeKJ4do16L36tYAFpX6 DK+9NlPnBZLRPpsYA1BnZDsHv67JlObgGvNjZ3OzgHrWOKoazRsG3MFgVWNF/6lN wIn5NaU3d2D19NVMA9pKY2rriHV38hxOTTRoRXqsgb3ch3uS8rSeq0yYJZDQXxC9 LFQlIVNZKxND7eFnOFhFt18IHolwaoiKO1z2oKkNy/GCsuA501F0E1RRk46WKlZD knDhJkuNgujX3BqaeIUCy0cuDsNlAjsHCDcbnbI+/lfFibVFYoVZRhYiGMc7NLrT Hr2swLh2AMPhZ4fFfUA6vX2p5szffWWFKvZQh0u0eB12yAOjp97Vc8T0dCxi/UHA == X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeduhedrfeelgdefvdcutefuodetggdotefrodftvf curfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfghnecu uegrihhlohhuthemuceftddtnecunecujfgurhepuffvhfffkfggtgfgsehtkeertddttd flnecuhfhrohhmpeeoghhrvghgkhhhsehlihhnuhigfhhouhhnuggrthhiohhnrdhorhhg qeenucffohhmrghinhepkhgvrhhnvghlrdhorhhgnecukfhppeekfedrkeeirdekledrud dtjeenucevlhhushhtvghrufhiiigvpedunecurfgrrhgrmhepmhgrihhlfhhrohhmpehg rhgvgheskhhrohgrhhdrtghomh X-ME-Proxy: Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) by mail.messagingengine.com (Postfix) with ESMTPA id D0FED3280064; Sat, 18 Apr 2020 06:40:02 -0400 (EDT) Subject: FAILED: patch "[PATCH] tracing: Fix the race between registering 'snapshot' event" failed to apply to 4.9-stable tree To: yangx.jy@cn.fujitsu.com, rostedt@goodmis.org Cc: From: Date: Sat, 18 Apr 2020 12:39:53 +0200 Message-ID: <1587206393189190@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 0bbe7f719985efd9adb3454679ecef0984cb6800 Mon Sep 17 00:00:00 2001 From: Xiao Yang Date: Tue, 14 Apr 2020 09:51:45 +0800 Subject: [PATCH] tracing: Fix the race between registering 'snapshot' event trigger and triggering 'snapshot' operation Traced event can trigger 'snapshot' operation(i.e. calls snapshot_trigger() or snapshot_count_trigger()) when register_snapshot_trigger() has completed registration but doesn't allocate buffer for 'snapshot' event trigger. In the rare case, 'snapshot' operation always detects the lack of allocated buffer so make register_snapshot_trigger() allocate buffer first. trigger-snapshot.tc in kselftest reproduces the issue on slow vm: ----------------------------------------------------------- cat trace ... ftracetest-3028 [002] .... 236.784290: sched_process_fork: comm=ftracetest pid=3028 child_comm=ftracetest child_pid=3036 <...>-2875 [003] .... 240.460335: tracing_snapshot_instance_cond: *** SNAPSHOT NOT ALLOCATED *** <...>-2875 [003] .... 240.460338: tracing_snapshot_instance_cond: *** stopping trace here! *** ----------------------------------------------------------- Link: http://lkml.kernel.org/r/20200414015145.66236-1-yangx.jy@cn.fujitsu.com Cc: stable@vger.kernel.org Fixes: 93e31ffbf417a ("tracing: Add 'snapshot' event trigger command") Signed-off-by: Xiao Yang Signed-off-by: Steven Rostedt (VMware) diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c index dd34a1b46a86..3a74736da363 100644 --- a/kernel/trace/trace_events_trigger.c +++ b/kernel/trace/trace_events_trigger.c @@ -1088,14 +1088,10 @@ register_snapshot_trigger(char *glob, struct event_trigger_ops *ops, struct event_trigger_data *data, struct trace_event_file *file) { - int ret = register_trigger(glob, ops, data, file); - - if (ret > 0 && tracing_alloc_snapshot_instance(file->tr) != 0) { - unregister_trigger(glob, ops, data, file); - ret = 0; - } + if (tracing_alloc_snapshot_instance(file->tr) != 0) + return 0; - return ret; + return register_trigger(glob, ops, data, file); } static int