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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 D1081C4360F for ; Wed, 27 Mar 2019 17:02:53 +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 55F0F206C0 for ; Wed, 27 Mar 2019 17:02:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 55F0F206C0 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kaod.org 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 44TvSq2CdHzDqPj for ; 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Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <7d97f3c6-4614-ead7-179a-e7e223ea3997@kaod.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-Ovh-Tracer-Id: 12263864735445257155 X-VR-SPAMSTATE: OK X-VR-SPAMSCORE: -100 X-VR-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrgedutddrkedvgdeklecutefuodetggdotefrodftvfcurfhrohhfihhlvgemucfqggfjpdevjffgvefmvefgnecuuegrihhlohhuthemucehtddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmd 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: tglx@linutronix.de, Paul Mackerras , Nicholas Piggin , David Gibson Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On 3/27/19 5:37 PM, Cédric Le Goater wrote: > On 3/27/19 1:36 PM, Sebastian Andrzej Siewior wrote: >> With qemu-system-ppc64le -machine pseries -smp 4 I get: >> >> |# chrt 1 hackbench >> |Running in process mode with 10 groups using 40 file descriptors each (== 400 tasks) >> |Each sender will pass 100 messages of 100 bytes >> | Oops: Exception in kernel mode, sig: 4 [#1] >> | LE PAGE_SIZE=64K MMU=Hash PREEMPT SMP NR_CPUS=2048 NUMA pSeries >> | Modules linked in: >> | CPU: 0 PID: 629 Comm: hackbench Not tainted 5.1.0-rc2 #71 >> | NIP: c000000000046978 LR: c000000000046a38 CTR: c0000000000b0150 >> | REGS: c0000001fffeb8e0 TRAP: 0700 Not tainted (5.1.0-rc2) >> | MSR: 8000000000089033 CR: 42000874 XER: 00000000 >> | CFAR: c000000000046a34 IRQMASK: 1 >> | GPR00: c0000000000b0170 c0000001fffebb70 c000000000a6ba00 0000000028000000 >> … >> | NIP [c000000000046978] doorbell_core_ipi+0x28/0x30 >> | LR [c000000000046a38] doorbell_try_core_ipi+0xb8/0xf0 >> | Call Trace: >> | [c0000001fffebb70] [c0000001fffebba0] 0xc0000001fffebba0 (unreliable) >> | [c0000001fffebba0] [c0000000000b0170] smp_pseries_cause_ipi+0x20/0x70 >> | [c0000001fffebbd0] [c00000000004b02c] arch_send_call_function_single_ipi+0x8c/0xa0 >> | [c0000001fffebbf0] [c0000000001de600] irq_work_queue_on+0xe0/0x130 >> | [c0000001fffebc30] [c0000000001340c8] rto_push_irq_work_func+0xc8/0x120 >> … >> | Instruction dump: >> | 60000000 60000000 3c4c00a2 384250b0 3d220009 392949c8 81290000 3929ffff >> | 7d231838 7c0004ac 5463017e 64632800 <7c00191c> 4e800020 3c4c00a2 38425080 >> | ---[ end trace eb842b544538cbdf ]--- >> >> and I was wondering whether this is a qemu bug or the kernel is using an >> opcode it should rather not. If I skip doorbell_try_core_ipi() in >> smp_pseries_cause_ipi() then there is no crash. The comment says "POWER9 >> should not use this handler" so… > > I would say Linux is using a msgsndp instruction which is not implemented > in QEMU TCG. But why have we started using dbells in Linux ? ah. It seems arch_local_irq_restore() / replay_interrupt() generated some interrupt. C.