Re: [syzbot] BUG: corrupted list in netif_napi_add

[Jakub Kicinski]

On Mon, 18 Oct 2021 17:04:19 +0300 Vlad Buslov wrote:
> We got a use-after-free with very similar trace [0] during nightly
> regression. The issue happens when ip link up/down state is flipped
> several times in loop and doesn't reproduce for me manually. The fact
> that it didn't reproduce for me after running test ten times suggests
> that it is either very hard to reproduce or that it is a result of some
> interaction between several tests in our suite.
> 
> [0]:
> 
> [ 3187.779569] mlx5_core 0000:08:00.0 enp8s0f0: Link up
>  [ 3187.890694] ==================================================================
>  [ 3187.892518] BUG: KASAN: use-after-free in __list_add_valid+0xc3/0xf0
>  [ 3187.894132] Read of size 8 at addr ffff8881150b3fb8 by task ip/119618

Hm, not sure how similar it is. This one looks like channel was freed
without deleting NAPI. Do you have list debug enabled?