On Wed, Jan 07, 2026 at 11:34:23AM +0800, Chen Zhen wrote:

If vlan dev was created with reorder_hdr off and hw offload both
off but up with hw offload on, it will trigger a skb_panic bug in
vlan_dev_hard_header().

Add a test to automatically catch re-occurrence of the issue.

Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Chen Zhen <redacted>

Shellcheck warns that cleanup is never invoked.

  SC2329 (info): This function is never invoked. Check usage (or ignored if invoked indirectly).

But is only true if only direct invocations are taken into
account (which I assume is what shellcheck does).
cleanup is actually called on exit as it has been
registered to do so by trap.

In order to keep shellcheck quiet I'd recommend adding the following
to vlan_hw_offload.sh.

#shellcheck disable=SC2329

...