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From: Alexander Monakov <amonakov@ispras.ru>
To: musl@lists.openwall.com
Subject: Re: [PATCH] replace 'hlt' by 'ud2' in i386/x32/x86_64 a_crash implementations
Date: Fri, 17 Apr 2015 11:12:20 +0300 (MSK)	[thread overview]
Message-ID: <alpine.LNX.2.11.1504171100550.3767@monopod.intra.ispras.ru> (raw)
In-Reply-To: <20150417055500.GW6817@brightrain.aerifal.cx>

On Fri, 17 Apr 2015, Rich Felker wrote:

> On Thu, Apr 16, 2015 at 08:58:59PM +0300, Alexander Monakov wrote:
> > ---
> > ud2 is also what GCC and Clang use to implement __builtin_trap()
> > 
> > ud2 causes SIGILL rather than SIGSEGV; SIGSEGV is more likely to have a custom
> > signal handler installed
> 
> I've pondered instead using:
> 
> 	push $-1
> 	mov $175,%eax
> 	xor %ebx,%ebx
> 	mov %esp,%ecx
> 	int $128
> 	hlt // or ud2?
> 
> This should be uncatchable but it's moderately larger. 

An argument in favor of plain hlt/ud2 is that registers and memory are
preserved, in case someone will be analyzing the coredump.

Alexander


  reply	other threads:[~2015-04-17  8:12 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-04-16 17:58 Alexander Monakov
2015-04-17  5:55 ` Rich Felker
2015-04-17  8:12   ` Alexander Monakov [this message]
2015-04-17 16:44     ` Rich Felker
2015-04-17 18:48       ` Alexander Monakov
2015-04-17 20:23         ` Rich Felker

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