Subject: Re: The _weirdest_ segfault...
To: Andreas Falck <faland-7@sm.luth.se>
From: David Brownlee <abs@netbsd.org>
List: port-alpha
Date: 05/17/2000 20:42:18
	Out of curiosity, what value are you passing to malloc()?


		David/absolute
				       -- www.netbsd.org: No hype required --

On Wed, 17 May 2000, Andreas Falck wrote:

> Hi!
> 
> I've been using NetBSD 1.4.1 on a 21164 for some while now. It's a pc164
> oem motherboard, nothing special about that. However, yesterday I ran into
> a weird thing that I cannot explain. I've had taken a course in unix
> system programming at my university, where the task was to develop a shell
> on FreeBSD (x86). When it was done I decided to port i to the alpha, and
> with a very few changes to the source code I made it compile without
> warnings (-Wall -Wpointer-arith -Wcast-align).
> Though, when trying to run it it failed very soon:
> 
> (gdb) run
> Starting program: /usr/home/andreas/src/amish/netbsd/amish 
> amish>pushd /usr
> 
> Program received signal SIGSEGV, Segmentation fault.
> 0x160541330 in malloc ()
> (gdb) backtrace
> #0  0x160541330 in malloc ()
> #1  0x1200062b0 in nexttoken () at tokenizer.c:126
> #2  0x120005888 in cmdparse (cmd=0x12010d060) at parser.c:278
> ...
> 
> **** Segfault in malloc!?! ****
> 
> Anyone knows or have an idea how it is possible? I could guess it might
> have something to do with wrong alignment, but shouldn't the kernel fix 
> such things? (my sysctl settings are such, according to the faq).
> 
> It's not that I need the shell running on my alpha (there are better
> shells :) but it would be interesting to know why it segfaults. The only
> libraries included is readline and ncurses.
> 
> /Andreas
> 
>