Re: [PATCH net] virtio_net: Do not pull payload in skb->head

On Sun, Apr 11, 2021 at 10:37 PM Guenter Roeck [off-list ref] wrote:

On 4/11/21 8:06 AM, Eric Dumazet wrote:

quoted

On Sun, Apr 11, 2021 at 3:43 PM Guenter Roeck [off-list ref] wrote:

quoted

This patch causes a virtio-net interface failure when booting sh4 images
in qemu. The test case is nothing special: Just try to get an IP address
using udhcpc. If it fails, udhcpc reports:

udhcpc: started, v1.33.0
udhcpc: sending discover
FAIL

Can you investigate where the incoming packet is dropped ?

Unless I am missing something, packets are not dropped. It looks more
like udhcpc gets bad indigestion in the receive path and exits immediately.
Plus, it doesn't happen all the time; sometimes it receives the discover
response and is able to obtain an IP address.

Overall this is quite puzzling since udhcpc exits immediately when the problem
is seen, no matter which option I give it on the command line; it should not
really do that.

Could you strace both cases and report differences you can spot ?

strace -o STRACE -f -s 1000 udhcpc