Re: [PATCH bpf-next] bpf:syscall: Log error code on trampoline unlink failure

[xu.xin16]

> >>> Well, the crash may happen when the kernel is booting, or too hard to reproduce,
> >>> in which case, bpftrace does not work.
> >>
> >>
> >> Do you enable kernel.panic_on_warn sysctl?
> >>
> >> If it's not enabled, the kernel won't crash, I think.
> > 
> > I'd like to clarify that the panic in our case is not triggered by the WARN itself.
> > Instead, the real crash is a use‑after‑free (UAF) that happens when one CPU is
> > executing a trampoline while another CPU is concurrently freeing it. This results
> > in an illegal instruction (or page fault) at the PC, which is fatal and will panic
> > the kernel regardless of panic_on_warn – because it's an Oops with Fatal exception
> > in interrupt.
> 
> 
> Why not fix the root cause instead?
> 
> If you want some help from upstream to fix the root cause, pls provide
> the crash dmesg and the reproducing demo.

It's already fixed due to some OOT drivers.

I think if we have this patch, it can speed up trouble-shooting.