linux-kernel - Re: [Bug Report] Linux v6.15-rc7 boot failure on Xen-4.17

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Message-ID: <1b8e565e-2ed6-4f1d-9138-fbf12662c404@suse.com>
Date: Wed, 28 May 2025 08:49:20 +0200
From: Juergen Gross <jgross@...e.com>
To: Xin Li <xin@...or.com>
Cc: Gupta Pawan <pawan.kumar.gupta@...ux.intel.com>,
 linux-kernel@...r.kernel.org, x86@...nel.org,
 Zijlstra Peter <peterz@...radead.org>,
 Hansen Dave <dave.hansen@...ux.intel.com>, alexandre.chartre@...cle.com,
 Andrew Cooper <andrew.cooper3@...rix.com>, Zhang Tao1 <tao1.zhang@...el.com>
Subject: Re: [Bug Report] Linux v6.15-rc7 boot failure on Xen-4.17

On 28.05.25 07:11, Jürgen Groß wrote:
> On 27.05.25 21:29, Andrew Cooper wrote:
>> On 27/05/2025 8:21 pm, Xin Li wrote:
>>>> On May 27, 2025, at 11:36 AM, Jürgen Groß <jgross@...e.com> wrote:
>>>>
>>>> On 27.05.25 19:54, Xin Li wrote:
>>>>> On 5/27/2025 10:46 AM, Pawan Gupta wrote:
>>>>>>> Attached is the serial console log and my kernel config.
>>>>>> Serial logs aren't telling much. I do not have a Xen setup to test, without
>>>>>> Xen the config that you provided is booting a KVM guest just fine.
>>>>> Yeah, as I replied to Juergen, the same kernel binary boots fine as
>>>>> "native".
>>>>> Unfortunately when booting as dom0 on Xen, it keeps rebooting w/o
>>>>> helpful log.
>>>> What about booting Xen on bare metal, i.e. no KVM being involved?
>>> The same exact problem happens on Intel Simics.  And I got to see it’s a NX 
>>> page fault in dom0 kernel during apply alternatives.
>>
>> In which case it's likely that there's an opencoded PTE update, rather
>> than using the hooks (which are suitably paravirt'd).
> 
> I'd suspect a bug when NOT using 2M pages for execmem.
> 
> I'll have a look.

Could you have a try using "nohugevmalloc" dom0 kernel boot parameter?


Juergen

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