Re: Kernel WARNING (RCU) with btnxpuart on TI AM62 platform

[Francesco Dolcini <francesco@dolcini.it>]

Hello,

On Tue, Apr 08, 2025 at 11:26:47AM +0200, Paul Menzel wrote:
> [Cc: +regressions@]
> 
> #regzbot introduced: v6.14..v6.15-rc1
> 
> 
> Thank you for your report.
> 
> Am 08.04.25 um 10:35 schrieb Francesco Dolcini:
> 
> > I do have the following kernel warning with 6.15-rc1, on a TI AM62
> > platform (arm64), single CPU core, using btnxpuart driver, any idea?
> > PREEMPT_RT is enabled, if it matters.
> > 
> > Either the issue is not systematic, or multi cores SoCs are not affected
> > (no error on the exact same image on a dual nor on quad core TI AM62).
> > 
> > 
> > [   23.139080] Voluntary context switch within RCU read-side critical section!
> > [   23.139119] WARNING: CPU: 0 PID: 61 at /kernel/rcu/tree_plugin.h:332 rcu_note_context_switch+0x3c4/0x430

...

> As I understood, that it’s a regression, and you can reproduce it, would it
> be possible, that you bisected the issue?

I am not sure if this is a regression. It's possible that the issue is not new,
and it is just non systematic. For sure it was reproduced by our CI on v6.15-rc1.

Francesco