Re: uprobe splat in PREEMP_RT

Sebastian Sewior
2025-04-02T12:13:18Z

On 2025-04-02 13:23:09 [+0200], Oleg Nesterov wrote:
> On 04/02, Sebastian Sewior wrote:
> >
> > On 2025-04-02 12:33:55 [+0200], Oleg Nesterov wrote:
> > >
> > > The "writer" ri_timer() can't race with itself, right?
> >
> > On PREEMPT_RT the timer could be preempted by a task with higher
> > priority and invoke hprobe_expire() somewhere else.
>
> This is clear, but ri_timer() still can not race with itself, no?

No, ri_timer() can not race against itself.
The preempted ri_timer() could stall a read_seqcount_begin(). Also not
the case. The API tries to prevent such things.

> Oleg.

Sebastian