lkml.org 
[lkml]   [2001]   [Nov]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: Generating a function call trace
On Fri, Nov 30, 2001 at 04:33:58PM +0100, Martin Dalecki wrote:
> Simon Turvey wrote:
> >
> > Is it possible to arbitrarily generate (in a module say) a function call
> > trace?
> >
>
> Just insert the dereference of a NULL pointer where you wan't to have
> it.
> The oops gives you what you wan't....
> Or better attach the gdb to /proc/kmem (you will have to compile the
> kernel with
> debugging on in front of this action) and have fun.

I'm using this ia32-only solution, as killing userspace program is not
acceptable under some conditions. Patch below was generated from
my 2.5.0-pre1 tree.
Petr Vandrovec
vandrove@vc.cvut.cz


diff -urdN linux/arch/i386/kernel/traps.c linux/arch/i386/kernel/traps.c
--- linux/arch/i386/kernel/traps.c Sun Sep 30 19:26:08 2001
+++ linux/arch/i386/kernel/traps.c Mon Nov 26 15:40:47 2001
@@ -237,6 +237,42 @@
printk("\n");
}

+void printstate(void) {
+ asm volatile (
+ "pushl %%ss\n\t"
+ "pushl %%esp\n\t"
+ "pushfl\n\t"
+ "pushl %%cs\n\t"
+ "call 1f\n"
+ "1:\n\t"
+ "pushl %%eax\n\t"
+ "pushl %%ds\n\t"
+ "pushl %%es\n\t"
+ "pushl %%eax\n\t"
+ "pushl %%ebp\n\t"
+ "pushl %%edi\n\t"
+ "pushl %%esi\n\t"
+ "pushl %%edx\n\t"
+ "pushl %%ecx\n\t"
+ "pushl %%ebx\n\t"
+ "movl %%esp,%%eax\n\t"
+ "pushl %%eax\n\t"
+ "call show_registers\n\t"
+ "addl $4,%%esp\n\t"
+ "popl %%ebx\n\t"
+ "popl %%ecx\n\t"
+ "popl %%edx\n\t"
+ "popl %%esi\n\t"
+ "popl %%edi\n\t"
+ "popl %%ebp\n\t"
+ "popl %%eax\n\t"
+ "popl %%es\n\t"
+ "popl %%ds\n\t"
+ "popl %%eax\n\t"
+ "addl $20,%%esp\n\t"
+ : : : "memory" );
+}
+
spinlock_t die_lock = SPIN_LOCK_UNLOCKED;

void die(const char * str, struct pt_regs * regs, long err)
diff -urdN linux/kernel/ksyms.c linux/kernel/ksyms.c
--- linux/kernel/ksyms.c Wed Nov 21 22:07:25 2001
+++ linux/kernel/ksyms.c Mon Nov 26 15:40:47 2001
@@ -71,6 +71,9 @@
};
#endif

+extern void printstate(void);
+
+EXPORT_SYMBOL(printstate);

EXPORT_SYMBOL(inter_module_register);
EXPORT_SYMBOL(inter_module_unregister);
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
\
 
 \ /
  Last update: 2005-03-22 13:13    [W:0.103 / U:5.180 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site