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 39A14E95A8E for ; Mon, 9 Oct 2023 13:52:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1377482AbjJINw1 (ORCPT ); Mon, 9 Oct 2023 09:52:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48324 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1377453AbjJINw0 (ORCPT ); Mon, 9 Oct 2023 09:52:26 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CF241B9 for ; Mon, 9 Oct 2023 06:52:24 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1D5EBC433C8; Mon, 9 Oct 2023 13:52:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1696859544; bh=xkBv8x1uVWv5XW3CGAbQT0MF/FyjjN+CBj/D54XZiFE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=b2rxO3OP57krjrFuarHc0UQnDnIjiJpA6m+ZenYCx6LkU5VHMY63VTW01nue/f33j qVmrXCoAPlLN6BdkJMVmG2wYQ6NdMAJlyD9rSMp8P8hIU+pRNkNPXY4wlOvSl8m6cC hmC3DbJdSgDmPfVGUZsJr8k9LeCOrhlhToWNl8bs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, mhiramat@kernel.org, Zheng Yejian , "Steven Rostedt (Google)" , Sasha Levin Subject: [PATCH 4.19 37/91] ring-buffer: Avoid softlockup in ring_buffer_resize() Date: Mon, 9 Oct 2023 15:06:09 +0200 Message-ID: <20231009130112.816856260@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231009130111.518916887@linuxfoundation.org> References: <20231009130111.518916887@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ 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 c8a7de7a1d635..320aa60664dc9 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1753,6 +1753,8 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size, err = -ENOMEM; goto out_err; } + + cond_resched(); } get_online_cpus(); -- 2.40.1