Subject: Re: [syzbot] BUG: corrupted list in netif_napi_add

From: Toke Høiland-Jørgensen <[email-masked]>
Date: Mon, 18 Oct 2021 19:40:40 +0200

Jakub Kicinski <[email-masked]> writes:

> 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?

Well, the other report[0] also kinda looks like the NAPI thread keeps
running after it should have been disabled, so maybe they are in fact
related?

-Toke

[0] https://lore.kernel.org/r/[email-masked]