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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 59C09C43603 for ; Thu, 19 Dec 2019 10:50:04 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A30AD21D7D for ; Thu, 19 Dec 2019 10:50:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="AjD211/D" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A30AD21D7D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=zx2c4.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 47dpYP3W6KzDqD8 for ; Thu, 19 Dec 2019 21:50:01 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=zx2c4.com (client-ip=192.95.5.64; helo=frisell.zx2c4.com; envelope-from=jason@zx2c4.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=zx2c4.com Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=zx2c4.com header.i=@zx2c4.com header.b="AjD211/D"; dkim-atps=neutral X-Greylist: delayed 397 seconds by postgrey-1.36 at bilbo; Thu, 19 Dec 2019 21:48:10 AEDT Received: from frisell.zx2c4.com (frisell.zx2c4.com [192.95.5.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 47dpWG6QbszDq7F for ; Thu, 19 Dec 2019 21:48:10 +1100 (AEDT) Received: by frisell.zx2c4.com (ZX2C4 Mail Server) with ESMTP id 3854f1e5; Thu, 19 Dec 2019 09:44:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=zx2c4.com; h=subject:to:cc :references:from:message-id:date:mime-version:in-reply-to :content-type:content-transfer-encoding; s=mail; bh=a1BPQtC+5hEE EkAeMYp4HKxJqFU=; b=AjD211/DOZy4eIxPRZRMywoytRStUf7wcBKZElKtQG1e oxApJ13C1o6UXOuU6IDyb9XiGmBudXXLTV/WptlaiVlrFqiKU8REq9FZmXIXwWJ3 NrTlm6/ou2aVNBKE63PUKttnHBjJ6NMdO8ENKmzAOc9LNgKsod3W7/bdRfLfrCPO fd7TeqAEcGCHJJD7dhqO+htsb57hxhaLmNsT1+121CGlktmD2KfIMMOzm81CT8SD ApEN8tdIY3iu4JSFlrLhp2JLTICHRex4PD+6i8eT0vzNgvynyJsk2B5DN7PM3bnf h2BNFIgonLjYPdvbBTwrJn5mWruCeF52dpCvlOxyDQ== Received: by frisell.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id 96e77a60 (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256:NO); Thu, 19 Dec 2019 09:44:45 +0000 (UTC) Subject: Re: [Qemu-ppc] pseries on qemu-system-ppc64le crashes in doorbell_core_ipi() To: Sebastian Andrzej Siewior , qemu-ppc@nongnu.org, linuxppc-dev@lists.ozlabs.org References: <20190327123615.rwhk6h3ayfurvapf@linutronix.de> <7d97f3c6-4614-ead7-179a-e7e223ea3997@kaod.org> <2bbc1490-400d-585e-d74b-924c570b4236@kaod.org> <1553836851.2264.2.camel@gmail.com> <1553850306.nyv11r9iej.astroid@bobo.none> <20190329113109.3a9bd24e@gandalf.local.home> <1553912871.ce5mzizoek.astroid@bobo.none> <20190401083827.GE11158@hirez.programming.kicks-ass.net> <20190406000611.GA27782@lenoir> <1554801792.ruzup3dxhe.astroid@bobo.none> From: "Jason A. Donenfeld" Message-ID: <7a5b63a0-2bf5-60bb-8678-b7b36671a29c@zx2c4.com> Date: Thu, 19 Dec 2019 11:41:21 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.3.0 MIME-Version: 1.0 In-Reply-To: <1554801792.ruzup3dxhe.astroid@bobo.none> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Zijlstra , Frederic Weisbecker , Frederic Weisbecker , Steven Rostedt , Paul Mackerras , Nicholas Piggin , Suraj Jitindar Singh , tglx@linutronix.de, David? Gibson , =?UTF-8?Q?C=c3=a9dric_Le_Goater?= Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Hi folks, I'm actually still experiencing this sporadically in the WireGuard test suite, which you can see being run on https://build.wireguard.com/ . About 50% of the time the powerpc64 build will fail at a place like this: [ 65.147823] Oops: Exception in kernel mode, sig: 4 [#1] [ 65.149198] LE PAGE_SIZE=4K MMU=Hash PREEMPT SMP NR_CPUS=4 NUMA pSeries [ 65.149595] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.5.0-rc1+ #1 [ 65.149745] NIP: c000000000033330 LR: c00000000007eda0 CTR: c00000000007ed80 [ 65.149934] REGS: c000000000a47970 TRAP: 0700 Not tainted (5.5.0-rc1+) [ 65.150032] MSR: 800000000288b033 CR: 48008288 XER: 00000000 [ 65.150352] CFAR: c0000000000332bc IRQMASK: 1 [ 65.150352] GPR00: c000000000036508 c000000000a47c00 c000000000a4c100 0000000000000001 [ 65.150352] GPR04: c000000000a50998 0000000000000000 c000000000a50908 000000000f509000 [ 65.150352] GPR08: 0000000028000000 0000000000000000 0000000000000000 c00000000ff24f00 [ 65.150352] GPR12: c00000000007ed80 c000000000ad9000 0000000000000000 0000000000000000 [ 65.150352] GPR16: 00000000008c9190 00000000008c94a8 00000000008c92f8 00000000008c98b0 [ 65.150352] GPR20: 00000000008f2f88 fffffffffffffffd 0000000000000014 0000000000e6c100 [ 65.150352] GPR24: 0000000000e6c100 0000000000000001 0000000000000000 c000000000a50998 [ 65.150352] GPR28: c000000000a9e280 c000000000a50aa4 0000000000000002 0000000000000000 [ 65.151591] NIP [c000000000033330] doorbell_try_core_ipi+0xd0/0xf0 [ 65.151750] LR [c00000000007eda0] smp_pseries_cause_ipi+0x20/0x70 [ 65.151913] Call Trace: [ 65.152109] [c000000000a47c00] [c0000000000c7c9c] _nohz_idle_balance+0xbc/0x300 (unreliable) [ 65.152370] [c000000000a47c30] [c000000000036508] smp_send_reschedule+0x98/0xb0 [ 65.152711] [c000000000a47c50] [c0000000000c1634] kick_ilb+0x114/0x140 [ 65.152962] [c000000000a47ca0] [c0000000000c86d8] newidle_balance+0x4e8/0x500 [ 65.153213] [c000000000a47d20] [c0000000000c8788] pick_next_task_fair+0x48/0x3a0 [ 65.153424] [c000000000a47d80] [c000000000466620] __schedule+0xf0/0x430 [ 65.153612] [c000000000a47de0] [c000000000466b04] schedule_idle+0x34/0x70 [ 65.153786] [c000000000a47e10] [c0000000000c0bc8] do_idle+0x1a8/0x220 [ 65.154121] [c000000000a47e70] [c0000000000c0e94] cpu_startup_entry+0x34/0x40 [ 65.154313] [c000000000a47ea0] [c00000000000ef1c] rest_init+0x10c/0x124 [ 65.154414] [c000000000a47ee0] [c000000000500004] start_kernel+0x568/0x594 [ 65.154585] [c000000000a47f90] [c00000000000a7cc] start_here_common+0x1c/0x330 [ 65.154854] Instruction dump: [ 65.155191] 38210030 e8010010 7c0803a6 4e800020 3d220004 39295228 81290000 3929ffff [ 65.155498] 7d284038 7c0004ac 5508017e 65082800 <7c00411c> e94d0178 812a0000 3929ffff [ 65.156155] ---[ end trace 6180d12e268ffdaf ]--- [ 65.185452] [ 66.187490] Kernel panic - not syncing: Fatal exception This is with "qemu-system-ppc64 -smp 4 -machine pseries" on QEMU 4.0.0. I'm not totally sure what's going on here. I'm emulating a pseries, and using that with qemu's pseries model, and I see that selecting the pseries forces the selection of 'config PPC_DOORBELL' (twice in the same section, actually). Then inside the kernel there appears to be some runtime CPU check for doorbell support. Is this a case in which QEMU is advertising doorbell support that TCG doesn't have? Or is something else happening here? Thanks, Jason