linux-kernel - Re: [PATCH 2.6.21-rc1] x86 signal number delivery fixes

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Message-Id: <200702252303.l1PN3eN1006022@harpo.it.uu.se>
Date:	Mon, 26 Feb 2007 00:03:40 +0100 (MET)
From:	Mikael Pettersson <mikpe@...uu.se>
To:	ak@...e.de
Cc:	linux-kernel@...r.kernel.org, torvalds@...ux-foundation.org
Subject: Re: [PATCH 2.6.21-rc1] x86 signal number delivery fixes

On Sun, 25 Feb 2007 23:39:48 +0100, Andi Kleen wrote:
> On Sunday 25 February 2007 12:47, Mikael Pettersson wrote:
> > The invokation of signal handlers on x86 has several bugs
> > in its treatment of the signal number parameter:
> > 
> > - the i386 kernel passes the raw not the translated signal number
> >   in EAX to non-SA_SIGINFO handlers compiled with -mregparm=3;
> >   the value passed on the stack is correct, and SA_SIGINFO handlers
> >   are also invoked correctly
> > - the x86-64 kernel's ia32 emulation for SA_SIGINFO handlers also
> >   passes the wrong (untranslated) signal number in EAX; the value
> >   on the stack is correct
> > - the x86-64 kernel's ia32 emulation for non-SA_SIGINFO handlers
> >   passes the wrong (untranslated) signal number both on the stack 
> >   and in EAX
> 
> 
> Nobody should be using that signal translation code anymore. Certainly
> nothing in tree. Perhaps it would be better to just rip it out.
> 
> If you have a user you should submit it.

The reason I noticed these issues was that I was studying the signal
delivery code for a virtualisation project, and these discrepancies
were immediately obvious just from reading the code.

I'm definitely not using that signal number translation feature; heck
I didn't even know it existed until a few days ago.

If it's dead as you say then it really ought to be removed. It currently
seems to make a mess in every arch's signal delivery code.

/Mikael
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