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a=ed25519-sha256; c=relaxed/relaxed; t=1789909500; s=strato-dkim-0003; d=xenosoft.de; h=In-Reply-To:Date:Message-ID:References:Cc:To:From:Subject:Cc:Date: From:Subject:Sender; bh=9Ak1CrscBpIUeZSB2TFLCl6Cj/LM1rn7lgmXEVu2Quo=; b=nll1Fe+QqhUFMzYUIr1X1mdMuEwcko5PuWRXdFSRuwckWWE23VKeuD58pbIi1I9PKe LBRg7bJboi0IFy+EEpAA== X-RZG-AUTH: ":L2QefEenb+UdBJSdRCXu93KJ1bmSGnhMdmOod1DhGN0rBVhd9dFr4thIFiqT9BURIS+l7hng" Received: from void-ppc.a-eon.tld by smtp.strato.de (RZmta 55.6.2 DYNA|AUTH) with ESMTPSA id ee2bee28KD4wJ1v (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Sun, 20 Sep 2026 15:04:58 +0200 (CEST) Subject: Re: [Linux PPC] Disable PREEMPT From: Christian Zigotzky To: =?UTF-8?Q?Michal_Such=c3=a1nek?= Cc: Shrikanth Hegde , "Christophe Leroy (CS GROUP)" , Michael Ellerman , harshpb@linux.ibm.com, Gautam Menghani , amachhiw@linux.ibm.com, linuxppc-dev , "kvm-ppc@vger.kernel.org" , Madhavan Srinivasan , Peter Zijlstra , "R.T.Dickinson" , hypexed@yahoo.com.au, mad skateman , Christian Zigotzky , Samir M , Venkat Rao Bagalkote , Narayana Murty N , Hari Bathini References: <25cf64ab-2a32-4d4c-a0c7-2e9007c276d4@linux.ibm.com> <9b58bd58-d0e4-463e-bff9-e33b153b2987@linux.ibm.com> <7ad57b61-4567-42c8-a9f6-faaabe7766a7@linux.ibm.com> <7e06fb84-ca2e-dbb4-47bd-e95ee11113c9@xenosoft.de> <79f9d4e3-ce55-d238-e4a9-b11e9ce27c5f@xenosoft.de> Organization: A-EON Open Source Message-ID: <33342fbf-eb7b-bde6-2c8c-254fe8bfb993@xenosoft.de> Date: Sun, 20 Sep 2026 15:04:57 +0200 X-Mailer: BrassMonkey/34.3.2.1 Precedence: bulk X-Mailing-List: kvm-ppc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: <79f9d4e3-ce55-d238-e4a9-b11e9ce27c5f@xenosoft.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 09/20/2026 01:49 PM, Christian Zigotzky wrote: > On 09/18/2026 09:10 AM, Michal Suchánek wrote: >> On Fri, Sep 18, 2026 at 04:39:57AM +0200, Christian Zigotzky wrote: >>> On 17/09/26 16:15, Shrikanth Hegde wrote: >>>> Hi Michal, >>>> >>>>>> Give it a try. >>>>>> >>>>>> I am suspecting both lockup, stack corruptions are secondary >>>>>> symptoms here. >>>>>> While recreate, I have different type of traces. >>>>> Yes, it does work for the crash I see. >>>> Thanks. Give me sometime to see further on that. Didn't get any time >>>> today. >>>> >>>>> However, we hijacked the report >>>>> of KVM locking up on FSL Cyrus+, and that is likely a different >>>>> problem >>>>> still not addressed. >>>>> >>>> Ah, that's what you meant. Yes, i still don't know where FSL Cyrus+ is >>>> stuck. >>>> >>>> I would need help from FSL Cyrus+ to get some logs or is there a >>>> way we >>>> can spin of >>>> a QEMU guest of it? We should have the log to start somewhere. >>>> >>>> >>> It's difficult to get a log because it freezes and can't write any >>> error >>> messages to the log files. This bug is very old. We had this issue some >>> years ago but we was able to disable PREEMPT because we don't need it. >> I would expect serial console and sysrq could give something, depending >> on how much of the kernel is frozen. >> >> Thanks >> >> Michal > Here is a serial log: > https://github.com/user-attachments/files/32433586/e5500_preempt_putty.log > Another serial log with pcie_ports=compat: https://github.com/user-attachments/files/32434487/e5500_preempt_pcie_ports_compat_putty.log -- Sent with BrassMonkey 34.3.2.1 (https://github.com/chzigotzky/Web-Browsers-and-Suites-for-Linux-PPC/releases/tag/BrassMonkey_34.3.2.1)