From: Przemek Kitszel <przemyslaw.kitszel@intel.com>
To: Viacheslav Tyryshkin <s@tyryshkin.me>,
<intel-wired-lan@lists.osuosl.org>, <netdev@vger.kernel.org>
Cc: Jedrzej Jagielski <jedrzej.jagielski@intel.com>,
Piotr Kwapulinski <piotr.kwapulinski@intel.com>
Subject: Re: [Intel-wired-lan] ixgbe: NULL-pointer panic in ixgbe_check_mdd_event() when SR-IOV disabled (num_vfs=0)
Date: Thu, 6 Aug 2026 11:14:02 +0200 [thread overview]
Message-ID: <abc23ed3-f194-4546-bf99-7152464b93e2@intel.com> (raw)
In-Reply-To: <0551d6fd-9f86-463a-86b5-c8dc78db62cd@smtp-relay.sendinblue.com>
On 8/3/26 16:47, Viacheslav Tyryshkin wrote:
> Hello
> I'm hitting the bug daily with Intel X550.
> please be informed, i may provide kernel dumps on request.
>
> ## One-line
> On an Intel X550 with **no VFs configured** (`sriov_numvfs=0`), a
> spurious MDD interrupt reaches `ixgbe_check_mdd_event()`, which writes
> into `adapter->vfinfo[]` without guarding for `num_vfs==0` — and
> `vfinfo` is NULL when SR-IOV is off → kernel panic in interrupt context.
> Reproduces roughly once a day under normal operation.
by looking at the code this is weird
ixgbe_handle_mdd_x550() reads two registers into wqbr, and the combined
read must be not-zero to trigger what you are observing
A patch will be much welcomed, given all the work you did with hunting
it down.
(avoid html, target at current iwl-net tree)
parent reply other threads:[~2026-08-06 9:14 UTC|newest]
Thread overview: expand[flat|nested] mbox.gz Atom feed
[parent not found: <0551d6fd-9f86-463a-86b5-c8dc78db62cd@smtp-relay.sendinblue.com>]
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