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 19077CE7A88 for ; Sun, 24 Sep 2023 13:23:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230369AbjIXNX6 (ORCPT ); Sun, 24 Sep 2023 09:23:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34652 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230339AbjIXNXo (ORCPT ); Sun, 24 Sep 2023 09:23:44 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 01DD6271B; Sun, 24 Sep 2023 06:20:47 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A45E4C433B9; Sun, 24 Sep 2023 13:20:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1695561647; bh=Op19wLQUKMEF56RN//vIr2TS8uWbFAexAY79fYfUeSQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Q7ebuWvDM7r5hasSpPCm3OopoV+xbqriTdzN7FsV4ubh3PHLfAhNT+xg8RgZ1M0x3 RnWK887dOScRNpcMFuen+p692u03BVqb7hNV04frwSHp40OMC5o9Ln9x9m0ImnmRQI 6iTK0yt24amtSZwjoqnBgDsVQDZcORFGU+AOAm57H/sP65slBzGDmHIZ3YRFNdwb4j gAjHH8pfDNRkXvtwPPl+NYy8w8Ixbw4oHW9xI/nh6RIBjoB4VzynOHbRZ4Yw+q2TNw 5KlxJCRD1ZR6VMCKHOQXGtEaZKaVjBgioNeLAQjElltZ4YQSyjoyyNZuefyX6BugTp 928HtYX1vK7Mg== 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 4.19 6/7] ring-buffer: Avoid softlockup in ring_buffer_resize() Date: Sun, 24 Sep 2023 09:20:30 -0400 Message-Id: <20230924132033.1276920-6-sashal@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230924132033.1276920-1-sashal@kernel.org> References: <20230924132033.1276920-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 4.19.295 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 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