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 387ECC4332F for ; Sun, 16 Oct 2022 15:21:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229738AbiJPPVz (ORCPT ); Sun, 16 Oct 2022 11:21:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50496 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229691AbiJPPVy (ORCPT ); Sun, 16 Oct 2022 11:21:54 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D384236BCD for ; Sun, 16 Oct 2022 08:21:53 -0700 (PDT) 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 ams.source.kernel.org (Postfix) with ESMTPS id 94829B80B66 for ; Sun, 16 Oct 2022 15:21:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0B2CBC433C1; Sun, 16 Oct 2022 15:21:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1665933711; bh=yTqrK+xJ8t8Ih3H1hrN4movzpX/8BjRKYBiIUQV1e9E=; h=Subject:To:Cc:From:Date:From; b=zwtvKGag3RvTZQxddoLhhPZ4ZKXkLpEXBM4WTLvfC+eAyol4Ms397WL8S9mRzha0l 7FUtZnmKhvw9gZy3XA9pV+A9x/rQDhhHiY20Mc6US6ETapbebDbTNy+doiWkUzMvVx MubGdC31F5BuJ6ZaMC/UgP/aRXzxitGYYbprAdvg= Subject: FAILED: patch "[PATCH] tracing: Wake up waiters when tracing is disabled" failed to apply to 5.4-stable tree To: rostedt@goodmis.org Cc: From: Date: Sun, 16 Oct 2022 17:22:26 +0200 Message-ID: <1665933746254224@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 5.4-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 . Possible dependencies: 2b0fd9a59b79 ("tracing: Wake up waiters when tracing is disabled") f3ddb74ad079 ("tracing: Wake up ring buffer waiters on closing of the file") efbbdaa22bb7 ("tracing: Show real address for trace event arguments") 8e99cf91b99b ("tracing: Do not allocate buffer in trace_find_next_entry() in atomic") ff895103a84a ("tracing: Save off entry when peeking at next entry") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 2b0fd9a59b7990c161fa1cb7b79edb22847c87c2 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Google)" Date: Wed, 28 Sep 2022 18:22:20 -0400 Subject: [PATCH] tracing: Wake up waiters when tracing is disabled When tracing is disabled, there's no reason that waiters should stay waiting, wake them up, otherwise tasks get stuck when they should be flushing the buffers. Cc: stable@vger.kernel.org Fixes: e30f53aad2202 ("tracing: Do not busy wait in buffer splice") Signed-off-by: Steven Rostedt (Google) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 58afc83afc9d..bb5597c6bfc1 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -8334,6 +8334,10 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos, if (ret) goto out; + /* No need to wait after waking up when tracing is off */ + if (!tracer_tracing_is_on(iter->tr)) + goto out; + /* Make sure we see the new wait_index */ smp_rmb(); if (wait_index != iter->wait_index) @@ -9065,6 +9069,8 @@ rb_simple_write(struct file *filp, const char __user *ubuf, tracer_tracing_off(tr); if (tr->current_trace->stop) tr->current_trace->stop(tr); + /* Wake up any waiters */ + ring_buffer_wake_waiters(buffer, RING_BUFFER_ALL_CPUS); } mutex_unlock(&trace_types_lock); }