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 8D16DEB64D9 for ; Wed, 14 Jun 2023 11:35:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244046AbjFNLfp (ORCPT ); Wed, 14 Jun 2023 07:35:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49272 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244038AbjFNLfn (ORCPT ); Wed, 14 Jun 2023 07:35:43 -0400 Received: from desiato.infradead.org (desiato.infradead.org [IPv6:2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 797B810D5 for ; Wed, 14 Jun 2023 04:35:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; 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; bh=FDiP6O9gPSQaPWMe9KEpB0x898vzzUW39aeiUbMsRBI=; b=HZm7VJAF8OKEfiMDDqIbvqSi6W TxIdm6caIor7s9K353ftlUNiAH1RNWAXsMvYJkFgPGrrMgiFxlfJXeEECzL2aSipZ6cIfnvyYp3EM Dbmh/Mubi97EqmmloS8uS25N/Y6bxN8/wpNcL1vh2L68RS2s2m750IEzPnVVoT9mPw/7ubKr9wJhe ZWYTI9f/TZj+A4YSAP52SLWtpQXs1KzJo61exn5Xv1MWQhUADRLTG/bpDVau+fdd28FOiY5eRgmXh S0ZwyMUVUiPutrxtP8uBFcZkijLbHpt54ghh+J6BbrJtZyEII1nVoHTKqyv7lgl7tLOD6B9AXSQpJ 6RJbmOsA==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.96 #2 (Red Hat Linux)) id 1q9Omm-00Ako9-33; Wed, 14 Jun 2023 11:35:37 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 921133002F0; Wed, 14 Jun 2023 13:35:36 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 7957D245CC9AB; Wed, 14 Jun 2023 13:35:36 +0200 (CEST) Date: Wed, 14 Jun 2023 13:35:36 +0200 From: Peter Zijlstra To: "Richard W.M. Jones" Cc: Aaron Thompson , linux-kernel@vger.kernel.org Subject: Re: printk.time causes rare kernel boot hangs Message-ID: <20230614113536.GJ1639749@hirez.programming.kicks-ass.net> References: <20230613134105.GA10301@redhat.com> <20230614092158.GF1639749@hirez.programming.kicks-ass.net> <20230614094522.GA7636@redhat.com> <20230614103011.GL7912@redhat.com> <20230614103953.GM7912@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230614103953.GM7912@redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 14, 2023 at 11:39:53AM +0100, Richard W.M. Jones wrote: > Got it! > > #0 arch_static_branch (branch=false, key=) > at ./arch/x86/include/asm/jump_label.h:27 > #1 static_key_false (key=) at ./include/linux/jump_label.h:207 > #2 native_write_msr (msr=1760, low=1876580734, high=106) > at ./arch/x86/include/asm/msr.h:147 > #3 0xffffffff8107997c in paravirt_write_msr (high=, > low=1876580734, msr=1760) at ./arch/x86/include/asm/paravirt.h:196 > #4 wrmsrl (val=, msr=1760) > at ./arch/x86/include/asm/paravirt.h:229 > #5 lapic_next_deadline (delta=, evt=) > at arch/x86/kernel/apic/apic.c:491 > #6 0xffffffff811f7b1d in clockevents_program_event (dev=0xffff88804e820dc0, > expires=, force=) > at kernel/time/clockevents.c:334 > #7 0xffffffff811f81b0 in tick_handle_periodic (dev=0xffff88804e820dc0) > at kernel/time/tick-common.c:133 > #8 0xffffffff810796c1 in local_apic_timer_interrupt () > at arch/x86/kernel/apic/apic.c:1095 > #9 __sysvec_apic_timer_interrupt (regs=regs@entry=0xffffc90000003ee8) > at arch/x86/kernel/apic/apic.c:1112 > #10 0xffffffff81f9cf09 in sysvec_apic_timer_interrupt (regs=0xffffc90000003ee8) > at arch/x86/kernel/apic/apic.c:1106 > #11 0xffffffff820015ca in asm_sysvec_apic_timer_interrupt () > at ./arch/x86/include/asm/idtentry.h:645 > #12 0x0000000000000000 in ?? () Uuuhh.. something is really fishy here. The thing in common between the fingered patch and this stacktrace is the jump_label/static_branch usage, but they're quite different paths. There is no printk or local_clock() in sight here. I've got that plain qemu thing running on: defconfig + kvm_guest.config + CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT=y and have added "nokaslr" to the -append string. Lets see if it wants to go wobbly for me.