What is the simplest method for generating an Oops? Browsing thru the
kernel mailing list archive, I came across a thread saying
*(int *)0=0;
generates on Oops. I wrote a program with this line in init_module.
compiled it as a module. On doing insmod, I got a panic. Is there a way
by which I can get it generate Oops rather than panic?
The reason is, on my machinee, when loading a kernel module with some bugs,
I get a panic rather than Oops. The two most common messages that I get are
"Unable to handle kernel NULL pointer dereference at virtual address"
and
"Unable to handle kernel paging request at virtual address"
After doing a search in linux-kernel mailing list archive, I found that
everybody gets these messages with Oops whereas I get it with panic. In
fact, I have never got an Oops on my machine. Any particular reason?
Thanks in advance,
Raju
Some info
1. cat /proc/version
Linux version 2.2.10 (root@linpqs) (gcc version egcs-2.91.66
19990314/Linux (egcs-1.1.2 release))6 Wed Nov 24 14:31:38 IST 1999
2. /usr/src/linux/scripts/ver_linux
-- Versions installed: (if some fields are empty or looks
-- unusual then possibly you have very old versions)
Linux linpqs 2.2.106 Wed Nov 24 14:31:38 IST 1999 i586 unknown
Kernel modules 2.1.121
Gnu C egcs-2.91.66
Binutils 2.9.4.0.6
Linux C Library 2.1.2
Dynamic linker ldd (GNU libc) 2.1.2
Procps 2.0.6
Mount 2.8a
Net-tools 1.50
Kbd 0.96
Sh-utils 1.16
Modules Loaded
3. cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 5
model : 2
model name : Pentium 75 - 200
stepping : 11
cpu MHz : 132.634331
fdiv_bug : no
hlt_bug : no
sep_bug : no
f00f_bug : yes
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 1
wp : yes
flags : fpu vme de pse tsc msr mce cx8
bogomips : 52.84
4. cat /proc/modules
empty
5. program which I wrote to simulate Oops:
#include <linux/kernel.h>
#include <linux/module.h>
#if CONFIG_MODVERSIONS==1
#define MODVERSIONS
#include
#<linux/modversions.h>
#endif
int init_module()
{
*(int *)0 = 0;
return 0;
}
void cleanup_module()
{
printk("removed module\n");
}
It was compiled as
gcc -Wall -DMODULE -D__KERNEL__ -DLINUX -O2 -c tempmod.c
insmod tempmod.o
caused panic with message
Unable to handle kernel NULL pointer dereference at virtual address 00000000
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