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 X-Spam-Level: X-Spam-Status: No, score=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E16E5C32789 for ; Fri, 2 Nov 2018 13:36:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 94AA82081B for ; Fri, 2 Nov 2018 13:36:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="qWUFuOrH" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 94AA82081B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727773AbeKBWnz (ORCPT ); Fri, 2 Nov 2018 18:43:55 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:33798 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726897AbeKBWnz (ORCPT ); Fri, 2 Nov 2018 18:43:55 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=381qpIJdfNrwhAI5Ppy/E9Kd3jq145yTVK2ml+2Oc4Q=; b=qWUFuOrHWWFo5/kQX0EPt7D8n Pr0YJ8YnzYXbq7TlpNDdVeucZLEo4JoZfjbo3delqG1CaPvfKiB5mmrfXfBW2KbMCtW6qt4rrKtnV CVAP8075vmoj6SpLokSvCFJv1tlT5kU+VGvilUsYdb/+9g2yJ6ggTfe5+PMg1Y9vQG3ngq5TZ8+47 JxAZtXB7Z82u7u09AtcoAm/VTGaT5+jXdiAEFgu9nnPKjp0uVrzaXXssiwCspt3n9HV2ej1IEG9gM IhEbjVDBTsnksQvv4UEnDt4roOUlf9W2TPduiovE77oJqg5qY2XmxmXsXpiiPe/ul8kovJWEd2LVd 0t/etYdGA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1gIZcm-0006Y5-H6; Fri, 02 Nov 2018 13:36:32 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id D377E2029F9FF; Fri, 2 Nov 2018 14:36:29 +0100 (CET) Date: Fri, 2 Nov 2018 14:36:29 +0100 From: Peter Zijlstra To: Tetsuo Handa Cc: Petr Mladek , Sergey Senozhatsky , Sergey Senozhatsky , Dmitriy Vyukov , Steven Rostedt , Alexander Potapenko , Fengguang Wu , Josh Poimboeuf , LKML , Linus Torvalds , Andrew Morton , linux-mm@kvack.org, Ingo Molnar , Will Deacon Subject: Re: [PATCH 3/3] lockdep: Use line-buffered printk() for lockdep messages. Message-ID: <20181102133629.GN3178@hirez.programming.kicks-ass.net> References: <1541165517-3557-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp> <1541165517-3557-3-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1541165517-3557-3-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Nov 02, 2018 at 10:31:57PM +0900, Tetsuo Handa wrote: > syzbot is sometimes getting mixed output like below due to concurrent > printk(). Mitigate such output by using line-buffered printk() API. > > RCU used illegally from idle CPU! > rcu_scheduler_active = 2, debug_locks = 1 > RSP: 0018:ffffffff88007bb8 EFLAGS: 00000286 > RCU used illegally from extended quiescent state! > ORIG_RAX: ffffffffffffff13 > 1 lock held by swapper/1/0: > RAX: dffffc0000000000 RBX: 1ffffffff1000f7b RCX: 0000000000000000 > #0: > RDX: 1ffffffff10237b8 RSI: 0000000000000001 RDI: ffffffff8811bdc0 > 000000004b34587c > RBP: ffffffff88007bb8 R08: ffffffff88075e00 R09: 0000000000000000 > ( > R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 > rcu_read_lock > R13: ffffffff88007c78 R14: 0000000000000000 R15: 0000000000000000 > ){....} > arch_safe_halt arch/x86/include/asm/paravirt.h:94 [inline] > default_idle+0xc2/0x410 arch/x86/kernel/process.c:498 > , at: trace_call_bpf+0xf8/0x640 kernel/trace/bpf_trace.c:46 WTH is that buffered aPI, and no, that breaks my earlyprintk stuff.