On 7/10/19 10:21 AM, Eric Biggers wrote:
> With my simplified reproducer, on commit 669de8bda87b ("kernel/workqueue: Use
> dynamic lockdep keys for workqueues") I see:
>
> WARNING: CPU: 3 PID: 189 at kernel/locking/lockdep.c:747
> register_lock_class+0x4f6/0x580
>
> and then somewhat later:
>
> BUG: MAX_LOCKDEP_KEYS too low!
>
> If on top of that I cherry pick commit 28d49e282665 ("locking/lockdep: Shrink
> struct lock_class_key"), I see instead:
>
> BUG: MAX_STACK_TRACE_ENTRIES too low!
>
> I also see that on mainline.
>
> Alternatively, if I check out 669de8bda87b and revert it, I don't see
> anything.
Hi Eric,
Is the rdma_ucm code the only code that triggers the "BUG:
MAX_STACK_TRACE_ENTRIES too low!" complaint or is this complaint also
triggered by other kernel code? I'm asking this because I think that
fixing this would require to implement garbage collection for the
stack_trace[] array in the lockdep code. That would make the lockdep
code slower. I don't think that making the lockdep code slower would be
welcome.
Bart.
