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 B2E86CE7A88 for ; Sun, 24 Sep 2023 13:32:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231671AbjIXNcY (ORCPT ); Sun, 24 Sep 2023 09:32:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38760 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231358AbjIXNbs (ORCPT ); Sun, 24 Sep 2023 09:31:48 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D1B7C126; Sun, 24 Sep 2023 06:19:16 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9A9D2C4339A; Sun, 24 Sep 2023 13:19:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1695561556; bh=K8J0QDkxbSrQUnC9nMsSjjLZcAM3sGpsS/OS8LrWF9g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=aC29fN7gZcwOmSDB0lHctCzVdf6dEkhSEnt9d0P8bGQ/ypn4AxDIUWGY/JmifRzDb /RNbKoOMVRK/BkC2coFY34Sq33pTthlBiYDNkpXJGKyeuYFSH2C6H0U65ddE5lmrlm tsYQCHMuGGpJ+aOu1czXAzDN5vOyEHAiOZ0Aoaq8Y7vVOEwQfQEk4ylvS071yg07eW fQSdvX1vtkJ6r7unE1n5t82C6eD8ngm/YuC9nGFsTSQz9V1AOeFfDQewLxfmyxp8Yq wKuDAaAFwAEkw1JPU+0eQYzVDuegsLNMqd9iqtKIwEGfyGnZB39WMHRTRk2WYNAL12 b1glWCmey+5sw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Zheng Yejian , mhiramat@kernel.org, Steven Rostedt , Sasha Levin , linux-trace-kernel@vger.kernel.org Subject: [PATCH AUTOSEL 5.15 08/18] ring-buffer: Avoid softlockup in ring_buffer_resize() Date: Sun, 24 Sep 2023 09:18:45 -0400 Message-Id: <20230924131857.1276330-8-sashal@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230924131857.1276330-1-sashal@kernel.org> References: <20230924131857.1276330-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 5.15.133 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Zheng Yejian [ Upstream commit f6bd2c92488c30ef53b5bd80c52f0a7eee9d545a ] When user resize all trace ring buffer through file 'buffer_size_kb', then in ring_buffer_resize(), kernel allocates buffer pages for each cpu in a loop. If the kernel preemption model is PREEMPT_NONE and there are many cpus and there are many buffer pages to be allocated, it may not give up cpu for a long time and finally cause a softlockup. To avoid it, call cond_resched() after each cpu buffer allocation. Link: https://lore.kernel.org/linux-trace-kernel/20230906081930.3939106-1-zhengyejian1@huawei.com Cc: Signed-off-by: Zheng Yejian Signed-off-by: Steven Rostedt (Google) Signed-off-by: Sasha Levin --- kernel/trace/ring_buffer.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index db7cefd196cec..b15d72284c7f7 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -2176,6 +2176,8 @@ int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size, err = -ENOMEM; goto out_err; } + + cond_resched(); } cpus_read_lock(); -- 2.40.1