On Tue, Nov 19, 2024 at 08:15:10AM +0100, Sebastian Andrzej Siewior wrote: > On 2024-11-18 21:19:28 [-0300], Luis Claudio R. Goncalves wrote: > > With PREEMPT_RT enabled some of the calls to tegra241_cmdqv_get_cmdq() > > during boot will happen in preemptible context. As this function calls > > smp_processor_id(), these calls will trigger a "BUG: using smp_processor_id() > > in preemptible" backtrace if DEBUG_PREEMPT is enabled. > > If this is only on PREEMPT_RT, where is the disabled preemption coming > from on !PREEMPT_RT? You are correct. This is not exclusive to PREEMPT_RT, also happens with the stock kernel. I ran more tests and this time I made sure DEBUG_PREEMPT was enabled. That was enough to reproduce the problem. > > As tegra241_cmdqv_get_cmdq() only calls smp_processor_id() to use the > > CPU number as a factor to balance out traffic on cmdq usage, it is safe > > to use raw_smp_processor_id() here. > > > > Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@xxxxxxxxxx> > > Sebastian > ---end quoted text---
