Re: [PATCH v3] lockdep: Allow tuning tracing capacity constants.

From: Tetsuo Handa
Date: Thu Nov 19 2020 - 08:45:52 EST


On 2020/11/19 22:06, Dmitry Vyukov wrote:
>>>>
>>>> I am trying to reproduce this locally first. syzbot caims it can
>>>> reproduce it with a number of very simpler reproducers (like spawn
>>>> process, unshare, create socket):
>>>> https://syzkaller.appspot.com/bug?id=8a18efe79140782a88dcd098808d6ab20ed740cc
>>>>
>>>> I see a very slow drift, but it's very slow, so get only to:
>>>> direct dependencies: 22072 [max: 32768]
>>>>
>>>> But that's running a very uniform workload.
>>>>
>>>> However when I tried to cat /proc/lockdep to see if there is anything
>>>> fishy already,
>>>> I got this (on c2e7554e1b85935d962127efa3c2a76483b0b3b6).
>>>>
>>>> Some missing locks?

Not a TOMOYO's bug. Maybe a lockdep's bug.

>
> But I don't know if it's enough to explain the overflow or not...
>

Since you can't hit the limit locally, I guess we need to ask syzbot to
run massive testcases.