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 6D65BE95A8E for ; Mon, 9 Oct 2023 13:30:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1377052AbjJINae (ORCPT ); Mon, 9 Oct 2023 09:30:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51656 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1377072AbjJINac (ORCPT ); Mon, 9 Oct 2023 09:30:32 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 359879D for ; Mon, 9 Oct 2023 06:30:30 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 74431C433C9; Mon, 9 Oct 2023 13:30:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1696858229; bh=sVEfaCBBFvzgZQeMknVtobRw9CQ+747b9wBq5RM6EGE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=p93wfh3YRgwYh/ZQl33R51R1dEstTT+gg5wZuFrYSb+WThsn8XD4+4jca5D4xqiB2 6KKFyICSl3J8h8a35KYJukF5ByJsgM4ypBU127iXKQpPWF2ejTbzAVLifc0pHZ++2/ Uqzo5mHVEdJphmxIGlBxP3y9xCncACphr6hder9I= 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 5.4 057/131] ring-buffer: Avoid softlockup in ring_buffer_resize() Date: Mon, 9 Oct 2023 15:01:37 +0200 Message-ID: <20231009130118.040559352@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231009130116.329529591@linuxfoundation.org> References: <20231009130116.329529591@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 5.4-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 445475c229b3a..2a4fb4f1e3cad 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1821,6 +1821,8 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size, err = -ENOMEM; goto out_err; } + + cond_resched(); } get_online_cpus(); -- 2.40.1