Date: Sat, 27 Apr 2013 19:05:15 +0000 From: "Wojciech A. Koszek" <wkoszek@freebsd.org> To: Kimmo Paasiala <kpaasial@gmail.com> Cc: freebsd-hackers@freebsd.org Subject: Re: config(8) -x headscratcher Message-ID: <20130427190514.GA85673@FreeBSD.org> In-Reply-To: <CA%2B7WWSeZ=Mg=-duGY-RHZ=n8vrJtDRM28jwCr1Szv4t_4Cdh%2Bw@mail.gmail.com> References: <CA%2B7WWSeZ=Mg=-duGY-RHZ=n8vrJtDRM28jwCr1Szv4t_4Cdh%2Bw@mail.gmail.com>
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On Sat, Apr 27, 2013 at 06:54:11PM +0300, Kimmo Paasiala wrote:
> I'm getting a core dump on 'config -x /boot/kernel/kernel' on 9.1-RELEASE i386.
>
> Assertion failed: (r != '\0' && ("Char present in the configuration "
> "string mustn't be equal to 0")), function kernconfdump, file
> /usr/src/usr.sbin/config/main.c, line 710.
>
> I have double checked that my config file is sane and does not have
> any funny characters anywhere.
>
> The system is i386 9.1-RELEASE r249856. The world and kernel are built
> with clang and I'm suspecting that the use of clang has something to
> do with this segfault.
>
> Looking at the kernel files I can see one very obvious difference.
> This is the 'elfdump -c kernel | grep -A 8 kern_conf' output (what
> config -x seems to use for finding out the config file from the kernel
> image) for the GENERIC kernel from the stock installation:
>
> sh_name: kern_conf
> sh_type: SHT_PROGBITS
> sh_flags: SHF_ALLOC
> sh_addr: 0xc1039f80
> sh_offset: 12820352
> sh_size: 3771
> sh_link: 0
> sh_info: 0
> sh_addralign: 32
>
> And this is from the kernel I have built myself using clang and a
> custom config file:
>
> sh_name: kern_conf
> sh_type: SHT_PROGBITS
> sh_flags: SHF_ALLOC
> sh_addr: 0xc09aee9c
> sh_offset: 5959324
> sh_size: 1994
> sh_link: 0
> sh_info: 0
> sh_addralign: 1
>
> The align field looks suspicious, config -x seems to use it to check
> for padding but to me it looks like the logic may not work if the
> alignment is 1.
>
> This the relevant bit from main.c of config(8)
>
Kimmo,
Lets keep discussion on hackers@ only. I do agree with you that config(8)
internal implementation might have its issues.
Can you make your kernel configuration file, faulty kernel image and exact
build instructions available to me?
--
Wojciech A. Koszek
wkoszek@FreeBSD.czest.pl
http://FreeBSD.czest.pl/~wkoszek/
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