Re: Debugging a (potentially?) ZFS-related panic, and discussion about large patchsets

On 11/01/2022 01:43, Mateusz Guzik wrote:
> imo the kernel should be patched to obtain the trace on its own. As
> the target has interrupts disabled it will have to do it with NMI, but
> support for that got scrapped in
> 
> commit 1c29da02798d968eb874b86221333a56393a94c3
> Author: Mark Johnston<markj@FreeBSD.org>
> Date:   Fri Jan 31 15:43:33 2020 +0000
> 
>      Reimplement stack capture of running threads on i386 and amd64.

This is an off-topic for the thread, but as far as I recall, even when the stack 
capture (e.g., for procstat -k) was implemented using NMI there was a piece of 
code in the corresponding NMI handler that skipped the stack tracing if 
interrupts were disabled.  I don't recall / know why.
You can see that in the removed stack_nmi_handler() that used to be in 
sys/x86/x86/stack_machdep.c.

-- 
Andriy Gapon