Re: [paulmck-rcu:dev.2025.08.13a] [tracing] 364ac25d46: WARNING:at_arch/x86/mm/fault.c:#do_user_addr_fault

[Paul E. McKenney]

On Wed, Sep 03, 2025 at 11:31:12AM -0400, Steven Rostedt wrote:
> On Wed, 3 Sep 2025 03:31:31 -0700
> "Paul E. McKenney" <paulmck@xxxxxxxxxx> wrote:
> 
> > > by applying the patch, the issue gone. but since you said this is a 'diagnostic
> > > patch', not sure if it's a real fix. anyway:
> > > 
> > > Tested-by: kernel test robot <oliver.sang@xxxxxxxxx>  
> > 
> > Thank you very much!  This tells me that something on the code path from
> > the tracepoint to the BPF program needs to have preemption disabled.
> > I will leave the diagnostic patch in my tree, and will be looking into
> > what the real fix should be.
> 
> Was it a BPF program that triggered this? I couldn't get that from the
> backtrace. Also, is this only a x86 32bit issue?

Excellent question, now that you mention it!  Your thought is that
one of the other preemption-disablings might need to be moved?

						Thanx, Paul