linux-kernel - Re: [PATCH] mshv: Make MSHV mutually exclusive with KEXEC

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: Windows password security audit tool. GUI, reports in PDF.

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

Message-ID: <549041d1-360d-d34c-4e3b-62802346acaa@linux.microsoft.com>
Date: Fri, 23 Jan 2026 16:16:33 -0800
From: Mukesh R <mrathor@...ux.microsoft.com>
To: Stanislav Kinsburskii <skinsburskii@...ux.microsoft.com>,
 kys@...rosoft.com, haiyangz@...rosoft.com, wei.liu@...nel.org,
 decui@...rosoft.com, longli@...rosoft.com
Cc: linux-hyperv@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mshv: Make MSHV mutually exclusive with KEXEC

On 1/23/26 14:20, Stanislav Kinsburskii wrote:
> The MSHV driver deposits kernel-allocated pages to the hypervisor during
> runtime and never withdraws them. This creates a fundamental incompatibility
> with KEXEC, as these deposited pages remain unavailable to the new kernel
> loaded via KEXEC, leading to potential system crashes upon kernel accessing
> hypervisor deposited pages.
> 
> Make MSHV mutually exclusive with KEXEC until proper page lifecycle
> management is implemented.
> 
> Signed-off-by: Stanislav Kinsburskii <skinsburskii@...ux.microsoft.com>
> ---
>   drivers/hv/Kconfig |    1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/hv/Kconfig b/drivers/hv/Kconfig
> index 7937ac0cbd0f..cfd4501db0fa 100644
> --- a/drivers/hv/Kconfig
> +++ b/drivers/hv/Kconfig
> @@ -74,6 +74,7 @@ config MSHV_ROOT
>   	# e.g. When withdrawing memory, the hypervisor gives back 4k pages in
>   	# no particular order, making it impossible to reassemble larger pages
>   	depends on PAGE_SIZE_4KB
> +	depends on !KEXEC
>   	select EVENTFD
>   	select VIRT_XFER_TO_GUEST_WORK
>   	select HMM_MIRROR
> 
> 

Will this affect CRASH kexec? I see few CONFIG_CRASH_DUMP in kexec.c
implying that crash dump might be involved. Or did you test kdump
and it was fine?

Thanks,
-Mukesh