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 EB8AFE95A8E for ; Mon, 9 Oct 2023 13:40:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1377318AbjJINkl (ORCPT ); Mon, 9 Oct 2023 09:40:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40396 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1376845AbjJINkk (ORCPT ); Mon, 9 Oct 2023 09:40:40 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 29866AB for ; Mon, 9 Oct 2023 06:40:39 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 67B4EC433C9; Mon, 9 Oct 2023 13:40:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1696858838; bh=yzWi5ezoAGkZ4QtSJ1OJfXxnW/9G3OA/vl+9hqjp4e8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FuwqlrHIm+QLm7Uf8nngo7sbmop0FcFxBXisw0EHUjNI8PC5omPadz8GnFC/ka/GV A+BWJzZttVV97uG/bSdeQPzky8EQtODwXRjtf0m2RP8UF4YhSWpJXffBOaEO5J8+zw UEjeY7nbfUJboMRFQnvfBfXoEMi1YZp0iN+ak38o= 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 5.10 115/226] ring-buffer: Avoid softlockup in ring_buffer_resize() Date: Mon, 9 Oct 2023 15:01:16 +0200 Message-ID: <20231009130129.783040931@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231009130126.697995596@linuxfoundation.org> References: <20231009130126.697995596@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 5.10-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 f8126fa0630e2..752e9549a59e8 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -2080,6 +2080,8 @@ int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size, err = -ENOMEM; goto out_err; } + + cond_resched(); } get_online_cpus(); -- 2.40.1