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 234DECE7A88 for ; Sun, 24 Sep 2023 13:36:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230520AbjIXNgo (ORCPT ); Sun, 24 Sep 2023 09:36:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38434 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231426AbjIXN3v (ORCPT ); Sun, 24 Sep 2023 09:29:51 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 63CCC5249; Sun, 24 Sep 2023 06:20:30 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E1EA6C433B7; Sun, 24 Sep 2023 13:20:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1695561629; bh=HYpkdOOghk0zSq3UiBqB7n4oHt5uTXUL0NsH5g3Gag4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eWBvsLBxWEbMutg/kMqG5Zucketj6NS+hPqzHlF76u+1SQWQHEA7iNu0sttyHf7gD HaB7loqg9jpPjFxcpSGTlL3JLelkT8Ha6DstQl81HRIy4ef7OR2vYjRodDbGFOTBkt +T9kPkO3nWX6qO5Ls/aS7OvfiuThfYJpxBhHIXSIODVZcfSNjZuZpeQCSOp4fWteFa EBGMekx5w1Yq9dj0DoApB7b42ixXUjWsnLRSM0ews7l3LMbHmIPy2fwwF+zGn7P/In ZZfbARhcZs272uy2xJEBig1Elg1EYpC11vddds9p/YnrWqZl58rt1SHQXxshgKGoWh c5oRj13jFusPQ== 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 5.4 6/7] ring-buffer: Avoid softlockup in ring_buffer_resize() Date: Sun, 24 Sep 2023 09:20:13 -0400 Message-Id: <20230924132015.1276811-6-sashal@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230924132015.1276811-1-sashal@kernel.org> References: <20230924132015.1276811-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 5.4.257 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 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