Re: BUG: ib_mad ftrace event unsupported migration

[Steven Rostedt]

On Wed, 2 Nov 2022 11:24:20 -0300
Jason Gunthorpe <jgg@xxxxxxxx> wrote:

> No, it doesn't muck with preemption, it will have some sleeping lock,
> eg mlx5_ib_query_pkey() does a memory allocation as the first thing
> 
> It seems like a bug that calling kmalloc(GFP_KERNEL)/might_sleep()
> from within a tracepoint doesn't trigger a warning?

Has nothing to do with tracepoints. You could call it a bug that it
doesn't trigger a warning when preemption is disabled. But then again,
it would if you enabled DEBUG_PREEMPT and possibly LOCKDEP too. So, I chalk
this up to a lack of proper testing.

-- Steve