Messages in this thread |  | | Date | Wed, 16 Sep 2020 13:50:57 +0200 | From | peterz@infradea ... | Subject | Re: [PATCH v2] lockdep: Allow tuning tracing capacity constants. |
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On Wed, Sep 16, 2020 at 01:28:19PM +0200, Dmitry Vyukov wrote: > On Fri, Sep 4, 2020 at 6:05 PM Tetsuo Handa > <penguin-kernel@i-love.sakura.ne.jp> wrote: > > > > Hello. Can we apply this patch? > > > > This patch addresses top crashers for syzbot, and applying this patch > > will help utilizing syzbot's resource for finding other bugs. > > Acked-by: Dmitry Vyukov <dvyukov@google.com> > > Peter, do you still have concerns with this?
Yeah, I still hate it with a passion; it discourages thinking. A bad annotation that blows up the lockdep storage, no worries, we'll just increase this :/
IIRC the issue with syzbot is that the current sysfs annotation is pretty terrible and generates a gazillion classes, and syzbot likes poking at /sys a lot and thus floods the system.
I don't know enough about sysfs to suggest an alternative, and haven't exactly had spare time to look into it either :/
Examples of bad annotations is getting every CPU a separate class, that leads to nr_cpus! chains if CPUs arbitrarily nest (nr_cpus^2 if there's only a single nesting level).
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