Re: git: 96c76d930656 - main - exit1(): Revert sparc64 workaround

On Sun, Aug 06, 2023 at 08:29:57PM +0000, Marius Strobl wrote:
> The branch main has been updated by marius:
> 
> URL: https://cgit.FreeBSD.org/src/commit/?id=96c76d930656f13d3c041dc8d8f2fc3dd1e5e05a
> 
> commit 96c76d930656f13d3c041dc8d8f2fc3dd1e5e05a
> Author:     Marius Strobl <marius@FreeBSD.org>
> AuthorDate: 2023-08-06 19:54:57 +0000
> Commit:     Marius Strobl <marius@FreeBSD.org>
> CommitDate: 2023-08-06 20:26:01 +0000
> 
>     exit1(): Revert sparc64 workaround
>     
>     If this still is a problem on other architectures, it should be fixed
>     properly.
>     
>     This reverts commit 5486ffc898503a846ecaf3f5ef9f9269beb4540e.
> ---
>  sys/kern/kern_exit.c | 8 +-------
>  1 file changed, 1 insertion(+), 7 deletions(-)
> 
> diff --git a/sys/kern/kern_exit.c b/sys/kern/kern_exit.c
> index cb0939ded6e1..e3345c14df26 100644
> --- a/sys/kern/kern_exit.c
> +++ b/sys/kern/kern_exit.c
> @@ -238,13 +238,7 @@ exit1(struct thread *td, int rval, int signo)
>  	TSPROCEXIT(td->td_proc->p_pid);
>  
>  	p = td->td_proc;
> -	/*
> -	 * XXX in case we're rebooting we just let init die in order to
> -	 * work around an unsolved stack overflow seen very late during
> -	 * shutdown on sparc64 when the gmirror worker process exists.
> -	 * XXX what to do now that sparc64 is gone... remove if?
> -	 */
> -	if (p == initproc && rebooting == 0) {
> +	if (p == initproc) {
>  		printf("init died (signal %d, exit %d)\n", signo, rval);
>  		panic("Going nowhere without my init!");
>  	}
I believe this was a right thing to do, regardless of the sparc64 stack
overflow. When rebooting NFS-booted machine, page-in over NFS stops
working, perhaps due to interface going down, while userspace is still
alive.  In this situation, pager returns KERN_FAILURE which translates
to SIGSEGV to userspace.  If init(8) process gets the signal, we would
panic instead of continuing the reboot.