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 EF305E7C4E7 for ; Wed, 4 Oct 2023 18:08:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243863AbjJDSIw (ORCPT ); Wed, 4 Oct 2023 14:08:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46072 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243856AbjJDSIv (ORCPT ); Wed, 4 Oct 2023 14:08:51 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 281CBD9 for ; Wed, 4 Oct 2023 11:08:48 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6DBDAC433C8; Wed, 4 Oct 2023 18:08:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1696442927; bh=LuEOjcyPAnwrVKnTw5Ep08ZIQfgTuFFPWah66aSBpjo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=afHT0bLe7KGpXV0QaBARrhAYpe0sv8jjZeI/aG0leVtOqinSjAl5z1cqaAI15hiQz cykc8Ake/AEqLygxZFPHXzJJ1Wid8OTWdEZpxBckMd+26aiGwyDSkRzcwtoGiYbywh pxlIbhyR3UX/tcc0U9COirlxyOxLJAndTux/7gTk= 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 5.15 120/183] ring-buffer: Avoid softlockup in ring_buffer_resize() Date: Wed, 4 Oct 2023 19:55:51 +0200 Message-ID: <20231004175208.970664941@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231004175203.943277832@linuxfoundation.org> References: <20231004175203.943277832@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 5.15-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 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