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 1EC82C433F5 for ; Sun, 23 Jan 2022 16:46:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238853AbiAWQqp (ORCPT ); Sun, 23 Jan 2022 11:46:45 -0500 Received: from sin.source.kernel.org ([145.40.73.55]:35676 "EHLO sin.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232833AbiAWQqo (ORCPT ); Sun, 23 Jan 2022 11:46:44 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id EC1BFCE0EDC for ; Sun, 23 Jan 2022 16:46:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id ABD19C340E5; Sun, 23 Jan 2022 16:46:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1642956401; bh=JILAxxZOINnT0uthY4XMvg6N8DhAOMoy9k8idVndY7E=; h=Subject:To:Cc:From:Date:From; b=r+vls/FGxMmmXRFV/+bcr+3Hv4sysxcmBkVz6MGVQ/B/r2Evl7CxXFl5CMhi+ILA/ Pk5CYZnqgjmYSpKDKji/Lz9CpD33DESIYXrnjG4HBlpLbNR/X6Q/4z/THLDQPpchHY nLOsdgQKRP9DfogCGqonWWceUBsn8V2TUBbVY2t8= Subject: FAILED: patch "[PATCH] tracing/osnoise: Properly unhook events if" failed to apply to 5.15-stable tree To: nikita.yushchenko@virtuozzo.com, bristot@kernel.org, rostedt@goodmis.org Cc: From: Date: Sun, 23 Jan 2022 17:46:38 +0100 Message-ID: <1642956398125157@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 5.15-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 0878355b51f5f26632e652c848a8e174bb02d22d Mon Sep 17 00:00:00 2001 From: Nikita Yushchenko Date: Sun, 9 Jan 2022 18:34:59 +0300 Subject: [PATCH] tracing/osnoise: Properly unhook events if start_per_cpu_kthreads() fails If start_per_cpu_kthreads() called from osnoise_workload_start() returns error, event hooks are left in broken state: unhook_irq_events() called but unhook_thread_events() and unhook_softirq_events() not called, and trace_osnoise_callback_enabled flag not cleared. On the next tracer enable, hooks get not installed due to trace_osnoise_callback_enabled flag. And on the further tracer disable an attempt to remove non-installed hooks happened, hitting a WARN_ON_ONCE() in tracepoint_remove_func(). Fix the error path by adding the missing part of cleanup. While at this, introduce osnoise_unhook_events() to avoid code duplication between this error path and normal tracer disable. Link: https://lkml.kernel.org/r/20220109153459.3701773-1-nikita.yushchenko@virtuozzo.com Cc: stable@vger.kernel.org Fixes: bce29ac9ce0b ("trace: Add osnoise tracer") Acked-by: Daniel Bristot de Oliveira Signed-off-by: Nikita Yushchenko Signed-off-by: Steven Rostedt diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c index 4719a848bf17..36d9d5be08b4 100644 --- a/kernel/trace/trace_osnoise.c +++ b/kernel/trace/trace_osnoise.c @@ -2122,6 +2122,13 @@ static int osnoise_hook_events(void) return -EINVAL; } +static void osnoise_unhook_events(void) +{ + unhook_thread_events(); + unhook_softirq_events(); + unhook_irq_events(); +} + /* * osnoise_workload_start - start the workload and hook to events */ @@ -2154,7 +2161,14 @@ static int osnoise_workload_start(void) retval = start_per_cpu_kthreads(); if (retval) { - unhook_irq_events(); + trace_osnoise_callback_enabled = false; + /* + * Make sure that ftrace_nmi_enter/exit() see + * trace_osnoise_callback_enabled as false before continuing. + */ + barrier(); + + osnoise_unhook_events(); return retval; } @@ -2185,9 +2199,7 @@ static void osnoise_workload_stop(void) stop_per_cpu_kthreads(); - unhook_irq_events(); - unhook_softirq_events(); - unhook_thread_events(); + osnoise_unhook_events(); } static void osnoise_tracer_start(struct trace_array *tr)