Re: [PATCH v2 0/4] perf: Make SIGTRAP and __perf_pending_irq() work on RT.

Sebastian Andrzej Siewior
2024-03-13T13:46:49Z

On 2024-03-13 10:28:41 [-0300], Arnaldo Carvalho de Melo wrote:
> > One part I don't get: did you let it run or did you kill it?
>
> If I let them run they will finish and exit, no exec_child remains.
>
> If I instead try to stop the loop that goes on forking the 100 of them,
> then the exec_child remain spinning.

Okay. So that problem only exists if you intervene. And you can
reproduce this odd behaviour with my patches but not without them,
right?

> > it shouldn't remain there for ever. And my guess, that it is in spinning
> > in userland and not in kernel.
>
> Checking that now, the stack is the one I posted:
>
> > > [root@nine ~]# cat /proc/24263/stack
> > > [<0>] irqentry_exit_to_user_mode+0x1c9/0x1e0
> > > [<0>] asm_sysvec_apic_timer_interrupt+0x16/0x20
> > > [root@nine ~]#

could you resolve irqentry_exit_to_user_mode+0x1c9/0x1e0, please?

> > I tried it on bare metal and VM and couldn't reproduce this.
>
> All my tests are in bare metal.

Would you mind sending me your .config? The shell is bash I guess. I
will try to reproduce your setup on another box…

> - Arnaldo

Sebastian