Re: [PATCH] Fix PPC signal handling of NODEFER, should not affect sa_mask

[Linus Torvalds <torvalds@osdl.org>]

On Tue, 9 Aug 2005, Steven Rostedt wrote:
>
> If this is indeed the way things should work. I'll go ahead and fix all
> the other architectures.

It does appear that this is what the standards describe in the section 
quoted by Chris.

On the other hand, the standard seems to be a bit confused according to 
google:

  "This mask is formed by taking the union of the current signal mask and
   the value of the sa_mask for the signal being delivered unless
   SA_NODEFER or SA_RESETHAND is set, and then including the signal being
   delivered. If and when the user's signal handler returns normally, the
   original signal mask is restored."

Quite frankly, the way I read it is actually the old Linux behaviour: the 
"unless SA_NODEFER or SA_RESETHAND is set" seems to be talking about the 
whole union of the sa_mask thing, _not_ just the "and the signal being 
delivered" part. Exactly the way the kernel currently does (except we 
should apparently _also_ do it for SA_RESETHAND).

So if we decide to change the kernel behaviour, I'd like this to be in -mm
for a while before merging (or merge _very_ early after 2.6.13). I could
imagine this confusing some existing binaries that had only been tested
with the old Linux behaviour, regardless of what a standard says. 
Especially since the standard itself is so confusing and badly worded.

Maybe somebody can tell what other systems do, since I assume the standard 
is trying to describe behaviour that actually exists in the wild..

		Linus
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/