linux-kernel - Re: [EXTERNAL] [PATCH] scsi: storvsc: Fix scheduling while atomic on PREEMPT

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <aafa4a1f-ceef-492e-a842-60d684b0b01e@siemens.com>
Date: Tue, 3 Feb 2026 07:10:19 +0100
From: Jan Kiszka <jan.kiszka@...mens.com>
To: Long Li <longli@...rosoft.com>, KY Srinivasan <kys@...rosoft.com>,
 Haiyang Zhang <haiyangz@...rosoft.com>, Wei Liu <wei.liu@...nel.org>,
 Dexuan Cui <DECUI@...rosoft.com>,
 "James E.J. Bottomley" <James.Bottomley@...senPartnership.com>,
 "Martin K. Petersen" <martin.petersen@...cle.com>,
 "linux-hyperv@...r.kernel.org" <linux-hyperv@...r.kernel.org>
Cc: "linux-scsi@...r.kernel.org" <linux-scsi@...r.kernel.org>,
 Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
 Florian Bezdeka <florian.bezdeka@...mens.com>,
 RT <linux-rt-users@...r.kernel.org>, Mitchell Levy <levymitchell0@...il.com>
Subject: Re: [EXTERNAL] [PATCH] scsi: storvsc: Fix scheduling while atomic on
 PREEMPT_RT

On 03.02.26 06:57, Jan Kiszka wrote:
> On 03.02.26 00:47, Long Li wrote:
>>> From: Jan Kiszka <jan.kiszka@...mens.com>
>>>
>>> This resolves the follow splat and lock-up when running with PREEMPT_RT
>>> enabled on Hyper-V:
>>
>> Hi Jan,
>>
>> It's interesting to know the use-case of running a RT kernel over Hyper-V.
>>
>> Can you give an example?
>>
> 
> - functional testing of an RT base image over Hyper-V
> - re-use of a common RT base image, without exploiting RT properties
> 
>> As far as I know, Hyper-V makes no RT guarantees of scheduling VPs for a VM.
> 
> This is well understood and not our goal. We only need the kernel to run
> correctly over Hyper-V with PREEMPT-RT enabled, and that is not the case
> right now.
> 
> Thanks,
> Jan
> 
> PS: Who had to idea to drop a virtual UART from Gen 2 VMs? Early boot
> guest debugging is true fun now...
> 

OK, after some guessing, the patched kernel boots again. So I think I
also fixed the broken vmbus IRQ patch by threading it under RT.
Currently building a kernel inside the VM while lockdep is enabled.
Boot-up and first minutes of building didn't trigger any complaints.
Will share later on.

Jan

-- 
Siemens AG, Foundational Technologies
Linux Expert Center