Bug#1120602: [REGRESSION 6.12.y] hyper-v: BUG: kernel NULL pointer dereference, address: 00000000000000a0: RIP: 0010:hv_uio_channel_cb+0xd/0x20 [uio_hv_generic]

To: Peter Morrow <pdmorrow@gmail.com>
Cc: Salvatore Bonaccorso <carnil@debian.org>, 1120602@bugs.debian.org, Long Li <longli@microsoft.com>, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, regressions@lists.linux.dev, stable@vger.kernel.org, John Starks <jostarks@microsoft.com>, Michael Kelley <mhklinux@outlook.com>, Tianyu Lan <tiala@microsoft.com>, "K. Y. Srinivasan" <kys@microsoft.com>, Haiyang Zhang <haiyangz@microsoft.com>, Wei Liu <wei.liu@kernel.org>, Dexuan Cui <decui@microsoft.com>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Bug#1120602: [REGRESSION 6.12.y] hyper-v: BUG: kernel NULL pointer dereference, address: 00000000000000a0: RIP: 0010:hv_uio_channel_cb+0xd/0x20 [uio_hv_generic]
From: Naman Jain <namjain@linux.microsoft.com>
Date: Wed, 26 Nov 2025 11:45:05 +0530
Message-id: <[🔎] d3f83ff0-2c4d-4698-a71d-1530b8a2bde7@linux.microsoft.com>
Reply-to: Naman Jain <namjain@linux.microsoft.com>, 1120602@bugs.debian.org
In-reply-to: <CAFcZKTyOcDqDJRB4sgN7Q-dabBU0eg7KKs=yBJhB=CNDyy7scQ@mail.gmail.com>
References: <[🔎] aRYjk4JBqHvVl-wN@eldamar.lan> <[🔎] 7a38c04d-4e54-4f1a-96fd-43f0f11ab97b@linux.microsoft.com> <[🔎] CAFcZKTwQgd9hrTaXnThML=+WG82TH3DK90FT1-WWsBSoRj7dRw@mail.gmail.com> <[🔎] 176298819854.487825.11724175116974643582.reportbug@p15v.lan> <[🔎] 18bcf829-04f9-46ec-a874-7c2b9338cf3d@linux.microsoft.com> <[🔎] aRei1DGOWy13GqvE@eldamar.lan> <[🔎] 25aff5ca-b5e1-4907-bd12-6571f8454146@linux.microsoft.com> <CAFcZKTyOcDqDJRB4sgN7Q-dabBU0eg7KKs=yBJhB=CNDyy7scQ@mail.gmail.com> <[🔎] 176298819854.487825.11724175116974643582.reportbug@p15v.lan>



On 11/21/2025 3:34 PM, Peter Morrow wrote:

Hi Naman/Salvatore,

Is it possible to get this fixed in the 6.1 LTS series too? I just ran
into this crash when moving from bookworm based Debian kernel
6.1.153-1 to 6.1.158-1. I saw that "uio_hv_generic: Let userspace take
care of interrupt mask" appeared in 6.1.156.

Thanks,
Peter.



Hi Peter,
Yes, I have sent a patch for older kernel versions as well.
I am working to fix the review comments and send new revisions.

Here is the link:
https://lore.kernel.org/all/20251115085937.2237-1-namjain@linux.microsoft.com/


Regards,
Naman

Reply to:

References:
- Bug#1120602: [REGRESSION 6.12.y] hyper-v: BUG: kernel NULL pointer dereference, address: 00000000000000a0: RIP: 0010:hv_uio_channel_cb+0xd/0x20 [uio_hv_generic]
  - From: Salvatore Bonaccorso <carnil@debian.org>
- Bug#1120602: [REGRESSION 6.12.y] hyper-v: BUG: kernel NULL pointer dereference, address: 00000000000000a0: RIP: 0010:hv_uio_channel_cb+0xd/0x20 [uio_hv_generic]
  - From: Naman Jain <namjain@linux.microsoft.com>
- Bug#1120602: [REGRESSION 6.12.y] hyper-v: BUG: kernel NULL pointer dereference, address: 00000000000000a0: RIP: 0010:hv_uio_channel_cb+0xd/0x20 [uio_hv_generic]
  - From: Peter Morrow <pdmorrow@gmail.com>
- Bug#1120602: hyper-v: BUG: kernel NULL pointer dereference, address: 00000000000000a0
  - From: Peter Morrow <pdmorrow@gmail.com>
- Bug#1120602: [REGRESSION 6.12.y] hyper-v: BUG: kernel NULL pointer dereference, address: 00000000000000a0: RIP: 0010:hv_uio_channel_cb+0xd/0x20 [uio_hv_generic]
  - From: Naman Jain <namjain@linux.microsoft.com>
- Bug#1120602: [REGRESSION 6.12.y] hyper-v: BUG: kernel NULL pointer dereference, address: 00000000000000a0: RIP: 0010:hv_uio_channel_cb+0xd/0x20 [uio_hv_generic]
  - From: Salvatore Bonaccorso <carnil@debian.org>
- Bug#1120602: [REGRESSION 6.12.y] hyper-v: BUG: kernel NULL pointer dereference, address: 00000000000000a0: RIP: 0010:hv_uio_channel_cb+0xd/0x20 [uio_hv_generic]
  - From: Naman Jain <namjain@linux.microsoft.com>

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