Subject: Re: Squid on Alpha blows up..
To: Jason Thorpe <>
From: Matthew Jacob <>
List: port-alpha
Date: 03/03/1999 12:07:00
>  > 
>  > hmm.  sigbus or not and message or not.  so processes on alphas don't
>  > get sigbus'ed at all (modulo the sysctl setting)?  would it
>  > "theoretically" be possible to do the same thing for other
>  > architectures?  i'm just curious...
> Well, a NetBSD/alpha process will get SIGBUS'd if it does other SIGBUS'able
> access :-)  i.e. accessing a nonexistent (vs. unmapped) memory location.

Shouldn't that be a SIGSEGV?

>  > >Also note that the NetBSD kernel will panic if unaligned access is
>  > >performed by the kernel, rather than by a user process.
>  > 
>  > certainly.  to where would it trap?
> Same unaligned access fault handler, but if the processor is in kernel
> mode when the fault occurs, the fault handler decides to panic, instead.

Historically SIGBUS was for memory actions that could not be handled due
to bus (i.e., 'path') problems. This includes alignment, but also width.
For example, a 32 bit access in VMED16 space should generate a SIGBUS.