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h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=ZtmtTGcbQXf2OxH9l0ABovAXH9TEnBTcTAmDhd1omvbfhmPaTxnc5KESxxq38b89i Fz36kYSFBIM3Z+fIfDEw77waYuIxzGwbslG6o6XLar378UgSlxG3PHUyGLcYVAnmjI OtZVMJuWKxxBfGmpp/g3J4oSKjlj52ri+EhlrcTVSoM/od/+G8/8yZUTxr1MVErXP0 pX0AFMna3x/ImJthORvOMLEbrOiQlDekg6P/YjKDjDA4WuCSoRSnf+E0VZmXJQYDYX Pj1zKEskJs2rmhCmblQMzdc4IhovTytOdkkaPCUYRTS1EPmvbBBDYN6alQrTBV+ecO AZwE2FKunMDeQ== Message-ID: Date: Sun, 25 May 2025 01:34:29 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [Bug Report] Linux v6.15-rc7 boot failure on Xen-4.17 To: =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= , "linux-kernel@vger.kernel.org" , "x86@kernel.org" Cc: Peter Zijlstra , Pawan Gupta , Dave Hansen , alexandre.chartre@oracle.com References: <3cd3b448-e0c7-4408-8a8b-e08bb3b350c3@zytor.com> <21456608-aa50-4d70-b201-b51764347804@suse.com> Content-Language: en-US From: Xin Li Autocrypt: addr=xin@zytor.com; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 5/24/2025 11:58 PM, Jürgen Groß wrote: >> Just noticed vanilla v6.15-rc7 fails to boot on Xen 4.17 (Ubuntu Xen >> package) in a KVM guest.  So I did a bisect, and it says: >> >> 872df34d7c51a79523820ea6a14860398c639b87 is the first bad commit >> commit 872df34d7c51a79523820ea6a14860398c639b87 >> Author: Peter Zijlstra >> Date:   Mon Oct 14 10:05:48 2024 -0700 >> >>      x86/its: Use dynamic thunks for indirect branches >> >> >> Attached is the serial console log and my kernel config. > > So you are saying that the host kernel is to blame, given that above > commit isn't in the dom0 kernel. No, it's the KVM guest. I didn't change host kernel during the bisecting. I didn't dig further, but it looks related to changes in: arch/x86/kernel/alternative.c > Can you start e.g. a normal Linux guest on that host? The same kernel binary boots fine as native. > Any host messages to be seen when that happens? [469584.422141] virbr0: port 1(vnet12) entered blocking state [469584.422149] virbr0: port 1(vnet12) entered disabled state [469584.422164] vnet12: entered allmulticast mode [469584.422297] vnet12: entered promiscuous mode [469584.422716] virbr0: port 1(vnet12) entered blocking state [469584.422721] virbr0: port 1(vnet12) entered listening state [469586.477553] virbr0: port 1(vnet12) entered learning state [469588.526074] virbr0: port 1(vnet12) entered forwarding state [469588.526082] virbr0: topology change detected, propagating [469624.321914] virbr0: port 1(vnet12) entered disabled state [469624.332737] vnet12 (unregistering): left allmulticast mode [469624.332743] vnet12 (unregistering): left promiscuous mode [469624.332765] virbr0: port 1(vnet12) entered disabled state Thanks! Xin