Re: [PATCH 0/5] srcu: Add lockdep coverage for atomic SRCU and fix IRQ-state bug

[Boqun Feng <boqun@kernel.org>]

On Mon, Sep 14, 2026 at 05:34:14PM +0800, Kunwu Chan wrote:
> The atomic SRCU fastpath enables synchronize_srcu_atomic() to be called                                   
> from contexts with interrupts disabled. This series extends the                                          
> rcutorture lockdep tests to cover the atomic SRCU path and fixes an                                       
> IRQ-state preservation bug discovered along the way.                                                      
>                                                                                                        
> Patch 1-2 add lockdep test coverage for atomic SRCU:                                                      
> - testtype 4: same-type atomic SRCU deadlock                                                            
> - testtype 5: atomic SRCU + raw spinlock dependency cycle                                               
> - testtype 6: rcu_read_lock() -> synchronize_srcu_atomic()                                               
>   legitimate nesting, must not trigger lockdep warning                                                  
>                                                                                                        
> Patch 3 fixes a bug where the synchronize_srcu_atomic() call chain                                        
> unconditionally re-enables interrupts on unlock, by switching to the                                      
> irqsave/irqrestore variants throughout the call chain.                                                    
>                                                                                                        
> Patch 4 fixes a pre-existing double nerrs count in the script.                                            
>                                                                                                        
> Patch 5 adds testtype 7: cross-CPU IRQ context mismatch detection,                                        
> where an atomic SRCU reader held with IRQs enabled on one CPU is                                          
> paired with synchronize_srcu_atomic() via IPI on another CPU.
>  

Acked-by: Boqun Feng <boqun@kernel.org>

Regards,
Boqun

> Kunwu Chan (5):
>   rcutorture: Add atomic SRCU lockdep support
>   selftests/rcutorture: Wire atomic SRCU into srcu_lockdep.sh
>   srcutree: Preserve IRQ state in synchronize_srcu_atomic() callchain
>   selftests/rcutorture: Fix double nerrs count in srcu_lockdep.sh
>   rcutorture: Add atomic SRCU cross-CPU IRQ context mismatch test
> 
>  kernel/rcu/rcutorture.c                       | 109 +++++++++++++++++-
>  kernel/rcu/srcutree.c                         |  42 ++++---
>  .../selftests/rcutorture/bin/srcu_lockdep.sh  |  77 ++++++++++++-
>  3 files changed, 205 insertions(+), 23 deletions(-)
> 
> -- 
> 2.43.0
> 
>