Re: [PATCH v1] irq_work: Fix use-after-free in irq_work_single on PREEMPT_RT

[Sebastian Andrzej Siewior]

On 2026-03-25 11:53:15 [-0400], Steven Rostedt wrote:
> On Wed, 25 Mar 2026 16:38:26 +0100
> Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> wrote:
> 
> > Most irq-work aren't free()ed since they are static and remain around.
> > There is no task assigned if there is no active waiter.
> > Wouldn't it be easier to kfree_rcu() the struct using the irq-work?
> 
> I guess we should add some kind of helper then. Like tracepoints have.
> 
>    tracepoint_synchronize_unregister()
> 
> Perhaps have a:
> 
>    irq_work_synchronize_free();
> 
> Or something like that to let developers know that they just can't safely free a
> structure that contains an irq_work?

That sounds great.

> -- Steve

Sebastian