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

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" [off-list ref] wrote:

quoted

quoted

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 <redacted>  

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