Re: [PATCH 01/12] task_work: Fix NMI race condition

[Steven Rostedt]

On Wed, 24 Sep 2025 09:59:49 +0200
Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:

>   __schedule()
>   // disable irqs
>       <NMI>
> 	  task_work_add(current, work, TWA_NMI_CURRENT);
>       </NMI>
>   // current = next;
>   // enable irqs
>       <IRQ>
> 	  task_work_set_notify_irq()
> 	  test_and_set_tsk_thread_flag(current,
>                                        TIF_NOTIFY_RESUME); // wrong task!
>       </IRQ>
>   // original task skips task work on its next return to user (or exit!)
> 
> Fixes: 466e4d801cd4 ("task_work: Add TWA_NMI_CURRENT as an additional notify mode.")
> Reported-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>

Reviewed-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>

-- Steve