From: Jamie Lokier <jamie@shareable.org>
To: Chris Lattner <sabre@nondot.org>
Cc: "Richard B. Johnson" <root@chaos.analogic.com>,
Davide Libenzi <davidel@xmailserver.org>,
linux-kernel@vger.kernel.org
Subject: Re: [x86] Access off the bottom of stack causes a segfault?
Date: Sat, 18 Oct 2003 00:55:26 +0100 [thread overview]
Message-ID: <20031017235526.GB21420@mail.shareable.org> (raw)
In-Reply-To: <Pine.LNX.4.44.0310141447300.4666-100000@nondot.org>
Chris Lattner wrote:
> Thanks to everyone for all of the answers. :) I guess the moral of the
> story is to not perform leaf function optimization on X86. At least
> frame-pointer elimination is still safe.
Chris,
You _can_ do the leaf optimisation, but you have to be more careful.
Firstly, you'll need to use sigaltstack() to ensure signals are not
delivered on the current stack.
Secondly, you'll need to install a SIGSEGV signal handler which
detects when the kernel doesn't like you accessing below %esp, and
forces the vma to expand by manipulating %esp and doing some accesses,
then returns.
-- Jamie
next prev parent reply other threads:[~2003-10-17 23:55 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-10-14 18:31 [x86] Access off the bottom of stack causes a segfault? Chris Lattner
2003-10-14 18:37 ` Davide Libenzi
2003-10-14 19:00 ` Chris Lattner
2003-10-14 18:45 ` Davide Libenzi
2003-10-14 19:28 ` Richard B. Johnson
2003-10-14 19:48 ` Chris Lattner
2003-10-17 23:55 ` Jamie Lokier [this message]
2003-10-14 20:47 ` Mikael Pettersson
2003-10-14 18:42 ` Brian Gerst
2003-10-14 18:49 ` Chris Lattner
2003-10-14 18:42 ` Petr Vandrovec
2003-10-14 19:02 ` Chris Lattner
2003-10-14 19:18 ` Richard B. Johnson
2003-10-14 20:43 ` H. Peter Anvin
2003-10-17 0:23 ` Eric W. Biederman
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