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 1DC73C4332F for ; Sun, 16 Oct 2022 15:32:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229607AbiJPPc0 (ORCPT ); Sun, 16 Oct 2022 11:32:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40536 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229803AbiJPPc0 (ORCPT ); Sun, 16 Oct 2022 11:32:26 -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 51E5833863 for ; Sun, 16 Oct 2022 08:32:24 -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 dfw.source.kernel.org (Postfix) with ESMTPS id E668660BC7 for ; Sun, 16 Oct 2022 15:32:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id CC2F7C433D6; Sun, 16 Oct 2022 15:32:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1665934343; bh=T4SzOKRxql77KLFTSfCCDU1gm6OBek9KvrGgvwKDuPY=; h=Subject:To:Cc:From:Date:From; b=bef5vE6MAvM9Gqse5sF8OohZPTfWjjM5IqXIUez/l1fgqZ9jAUYr2gpWu43K1rZ9/ R1SPCp1fBFbnvlseth9I1lw1CzXWWxO/bWpylBf+wDkuynLKTqmSgv4kE+Tlni54hM M9nHijhbUdkNo8l1ByZh5MPYscfFZBOh9XkwgXBA= Subject: FAILED: patch "[PATCH] ring-buffer: Add ring_buffer_wake_waiters()" failed to apply to 4.14-stable tree To: rostedt@goodmis.org, akpm@linux-foundation.org, mingo@kernel.org Cc: From: Date: Sun, 16 Oct 2022 17:33:09 +0200 Message-ID: <1665934389132239@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 4.14-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: 7e9fbbb1b776 ("ring-buffer: Add ring_buffer_wake_waiters()") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 7e9fbbb1b776d8d7969551565bc246f74ec53b27 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Google)" Date: Wed, 28 Sep 2022 13:39:38 -0400 Subject: [PATCH] ring-buffer: Add ring_buffer_wake_waiters() On closing of a file that represents a ring buffer or flushing the file, there may be waiters on the ring buffer that needs to be woken up and exit the ring_buffer_wait() function. Add ring_buffer_wake_waiters() to wake up the waiters on the ring buffer and allow them to exit the wait loop. Link: https://lkml.kernel.org/r/20220928133938.28dc2c27@gandalf.local.home Cc: stable@vger.kernel.org Cc: Ingo Molnar Cc: Andrew Morton Fixes: 15693458c4bc0 ("tracing/ring-buffer: Move poll wake ups into ring buffer code") Signed-off-by: Steven Rostedt (Google) diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h index dac53fd3afea..2504df9a0453 100644 --- a/include/linux/ring_buffer.h +++ b/include/linux/ring_buffer.h @@ -101,7 +101,7 @@ __ring_buffer_alloc(unsigned long size, unsigned flags, struct lock_class_key *k int ring_buffer_wait(struct trace_buffer *buffer, int cpu, int full); __poll_t ring_buffer_poll_wait(struct trace_buffer *buffer, int cpu, struct file *filp, poll_table *poll_table); - +void ring_buffer_wake_waiters(struct trace_buffer *buffer, int cpu); #define RING_BUFFER_ALL_CPUS -1 diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 5a7d818ca3ea..3046deacf7b3 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -413,6 +413,7 @@ struct rb_irq_work { struct irq_work work; wait_queue_head_t waiters; wait_queue_head_t full_waiters; + long wait_index; bool waiters_pending; bool full_waiters_pending; bool wakeup_full; @@ -924,6 +925,37 @@ static void rb_wake_up_waiters(struct irq_work *work) } } +/** + * ring_buffer_wake_waiters - wake up any waiters on this ring buffer + * @buffer: The ring buffer to wake waiters on + * + * In the case of a file that represents a ring buffer is closing, + * it is prudent to wake up any waiters that are on this. + */ +void ring_buffer_wake_waiters(struct trace_buffer *buffer, int cpu) +{ + struct ring_buffer_per_cpu *cpu_buffer; + struct rb_irq_work *rbwork; + + if (cpu == RING_BUFFER_ALL_CPUS) { + + /* Wake up individual ones too. One level recursion */ + for_each_buffer_cpu(buffer, cpu) + ring_buffer_wake_waiters(buffer, cpu); + + rbwork = &buffer->irq_work; + } else { + cpu_buffer = buffer->buffers[cpu]; + rbwork = &cpu_buffer->irq_work; + } + + rbwork->wait_index++; + /* make sure the waiters see the new index */ + smp_wmb(); + + rb_wake_up_waiters(&rbwork->work); +} + /** * ring_buffer_wait - wait for input to the ring buffer * @buffer: buffer to wait on @@ -939,6 +971,7 @@ int ring_buffer_wait(struct trace_buffer *buffer, int cpu, int full) struct ring_buffer_per_cpu *cpu_buffer; DEFINE_WAIT(wait); struct rb_irq_work *work; + long wait_index; int ret = 0; /* @@ -957,6 +990,7 @@ int ring_buffer_wait(struct trace_buffer *buffer, int cpu, int full) work = &cpu_buffer->irq_work; } + wait_index = READ_ONCE(work->wait_index); while (true) { if (full) @@ -1021,6 +1055,11 @@ int ring_buffer_wait(struct trace_buffer *buffer, int cpu, int full) } schedule(); + + /* Make sure to see the new wait index */ + smp_rmb(); + if (wait_index != work->wait_index) + break; } if (full)