Re: [PATCH net 0/2] gve: fix crashes on invalid TX queue indices

[Eric Dumazet]

On Thu, Jan 8, 2026 at 4:36 PM Ankit Garg <nktgrg@xxxxxxxxxx> wrote:
>
> On Tue, Jan 6, 2026 at 6:22 PM Jakub Kicinski <kuba@xxxxxxxxxx> wrote:
> >
> > On Mon,  5 Jan 2026 15:25:02 -0800 Joshua Washington wrote:
> > > This series fixes a kernel panic in the GVE driver caused by
> > > out-of-bounds array access when the network stack provides an invalid
> > > TX queue index.
> >
> > Do you know how? I seem to recall we had such issues due to bugs
> > in the qdisc layer, most of which were fixed.
> >
> > Fixing this at the source, if possible, would be far preferable
> > to sprinkling this condition to all the drivers.
> That matches our observation—we have encountered this panic on older
> kernels (specifically Rocky Linux 8) but have not been able to
> reproduce it on recent upstream kernels.

What is the kernel version used in Rocky Linux 8 ?

Note that the test against real_num_tx_queues is done before reaching
the Qdisc layer.

It might help to give a stack trace of a panic.

>
> Could you point us to the specific qdisc fixes you recall? We'd like
> to verify if the issue we are seeing on the older kernel is indeed one
> of those known/fixed bugs.
>
> If it turns out this is fully resolved in the core network stack
> upstream, we can drop this patch for the mainline driver. However, if
> there is ambiguity, do you think there is value in keeping this check
> to prevent the driver from crashing on invalid input?

We already have many costly checks, and netdev_core_pick_tx() should
already prevent such panic.

>
> Thanks,
> Ankit Garg