* Simple piece of code with unexpected behavior
@ 2011-08-11 12:29 Roland Vossen
2011-08-11 12:44 ` David Miller
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Roland Vossen @ 2011-08-11 12:29 UTC (permalink / raw)
To: sparclinux
Hi,
after compiling and insmodding a module on a Sparc64 machine, the
following piece of code:
u8 index;
for (index = 0; index < 128U; index++) {
if (index=129) {
printk("fishy...\n");
break;
}
}
produces the log message: 'fishy...'.
The same piece of code does not produce this message on x86.
Is this a compiler bug, or am I overlooking something ?
Thanks, Roland.
--- info on my machine
developer@LB-BUN-44:~/code/brcm80211-next-2.6$ uname -a
Linux LB-BUN-44.bun.broadcom.com 3.0.0-rc6+ #2 Fri Jul 22 17:00:50 CEST
2011 sparc64 GNU/Linux
--- info on my GCC version
developer@LB-BUN-44:~/code/brcm80211-next-2.6$ gcc -v
Using built-in specs.
Target: sparc-linux-gnu
Configured with: ../src/configure -v
--enable-languages=c,c++,fortran,objc,obj-c++,treelang --prefix=/usr
--enable-shared --with-system-zlib --libexecdir=/usr/lib
--without-included-gettext --enable-threads=posix --enable-nls
--with-gxx-include-dir=/usr/include/c++/4.2 --program-suffix=-4.2
--enable-clocale=gnu --enable-libstdcxx-debug --enable-objc-gc
--enable-mpfr --with-cpu=v8 --with-long-double-128
--enable-checking=release --build=sparc-linux-gnu --host=sparc-linux-gnu
--target=sparc-linux-gnu
Thread model: posix
gcc version 4.2.4 (Ubuntu 4.2.4-1ubuntu4)
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Simple piece of code with unexpected behavior
2011-08-11 12:29 Simple piece of code with unexpected behavior Roland Vossen
@ 2011-08-11 12:44 ` David Miller
2011-08-11 14:18 ` Roland Vossen
2011-08-11 14:34 ` David Miller
2 siblings, 0 replies; 4+ messages in thread
From: David Miller @ 2011-08-11 12:44 UTC (permalink / raw)
To: sparclinux
From: "Roland Vossen" <rvossen@broadcom.com>
Date: Thu, 11 Aug 2011 14:29:03 +0200
> after compiling and insmodding a module on a Sparc64 machine, the
> following piece of code:
>
> u8 index;
> for (index = 0; index < 128U; index++) {
> if (index=129) {
> printk("fishy...\n");
> break;
> }
> }
>
> produces the log message: 'fishy...'.
Something is very wrong with your build environment:
--------------------
root@firepit:/home/davem# cat Makefile
obj-m := test_mod.o
root@firepit:/home/davem# cat test_mod.c
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
static int __init test(void)
{
u8 index;
for (index = 0; index < 128U; index++) {
if (index=129) {
printk("fishy...\n");
break;
}
}
return 0;
}
module_init(test);
root@firepit:/home/davem#
root@firepit:/home/davem# make -C /home/davem/src/GIT/linux M=$(pwd)
make: Entering directory `/home/davem/src/GIT/linux'
CC [M] /home/davem/test_mod.o
Building modules, stage 2.
MODPOST 1 modules
LD [M] /home/davem/test_mod.ko
make: Leaving directory `/home/davem/src/GIT/linux'
root@firepit:/home/davem# insmod ./test_mod.ko
--------------------
Generates no warning "fishy" message for me on sparc64.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Simple piece of code with unexpected behavior
2011-08-11 12:29 Simple piece of code with unexpected behavior Roland Vossen
2011-08-11 12:44 ` David Miller
@ 2011-08-11 14:18 ` Roland Vossen
2011-08-11 14:34 ` David Miller
2 siblings, 0 replies; 4+ messages in thread
From: Roland Vossen @ 2011-08-11 14:18 UTC (permalink / raw)
To: sparclinux
> Something is very wrong with your build environment:
Thanks for doing this experiment David. Can you email me some details on
the build chain you are using: eg, output of 'gcc -v'? Did you cross
compile gcc yourself or did you download a binary ?
Thanks, Roland.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Simple piece of code with unexpected behavior
2011-08-11 12:29 Simple piece of code with unexpected behavior Roland Vossen
2011-08-11 12:44 ` David Miller
2011-08-11 14:18 ` Roland Vossen
@ 2011-08-11 14:34 ` David Miller
2 siblings, 0 replies; 4+ messages in thread
From: David Miller @ 2011-08-11 14:34 UTC (permalink / raw)
To: sparclinux
From: "Roland Vossen" <rvossen@broadcom.com>
Date: Thu, 11 Aug 2011 16:18:53 +0200
>> Something is very wrong with your build environment:
>
> Thanks for doing this experiment David. Can you email me some details
> on the build chain you are using: eg, output of 'gcc -v'? Did you
> cross compile gcc yourself or did you download a binary ?
It's native debian unstable which uses gcc-4.6.1
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2011-08-11 14:34 UTC | newest]
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2011-08-11 12:29 Simple piece of code with unexpected behavior Roland Vossen
2011-08-11 12:44 ` David Miller
2011-08-11 14:18 ` Roland Vossen
2011-08-11 14:34 ` David Miller
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