linux/include/asm-x86_64/kdebug.h
Andi Kleen daeeafecf0 [PATCH] x86_64: Keep only a single debug notifier chain
Calling a notifier three times in the debug handler does not make much sense,
because a debugger can figure out the various conditions by itself.  Remove
the additional calls to DIE_DEBUG and DIE_DEBUGSTEP completely.

This matches what i386 does now.

This also makes sure interrupts are always still disabled when calling a
debugger, which prevents:

BUG: using smp_processor_id() in preemptible [00000001] code: tpopf/1470
caller is post_kprobe_handler+0x9/0x70

Call Trace:<ffffffff8024f10f>{smp_processor_id+191} <ffffffff80120e69>{post_kpro
be_handler+9} 
<ffffffff80120f7a>{kprobe_exceptions_notify+58} 
<ffffffff80144fc0>{notifier_call_chain+32} <ffffffff80110daf>{do_debug+335} 
<ffffffff8010f513>{debug+127}  <EOE> 

on preemptible debug kernels with kprobes when single stepping in user space.

This was probably a bug even on non preempt kernels, this function was
supposed to be running with interrupts off according to a comment there.

Note to third part debugger maintainers: please double check your debugger can
still single step.

Cc: <prasanna@in.ibm.com>
Cc: <jbeulich@novell.com>
Cc: <kaos@sgi.com>
Cc: <jim.houston@ccur.com>
Cc: <jfv@bluesong.net>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-04-16 15:25:13 -07:00

53 lines
1.2 KiB
C

#ifndef _X86_64_KDEBUG_H
#define _X86_64_KDEBUG_H 1
#include <linux/notifier.h>
struct pt_regs;
struct die_args {
struct pt_regs *regs;
const char *str;
long err;
int trapnr;
int signr;
};
/* Note - you should never unregister because that can race with NMIs.
If you really want to do it first unregister - then synchronize_kernel - then free.
*/
int register_die_notifier(struct notifier_block *nb);
extern struct notifier_block *die_chain;
/* Grossly misnamed. */
enum die_val {
DIE_OOPS = 1,
DIE_INT3,
DIE_DEBUG,
DIE_PANIC,
DIE_NMI,
DIE_DIE,
DIE_NMIWATCHDOG,
DIE_KERNELDEBUG,
DIE_TRAP,
DIE_GPF,
DIE_CALL,
DIE_NMI_IPI,
DIE_PAGE_FAULT,
};
static inline int notify_die(enum die_val val,char *str,struct pt_regs *regs,long err,int trap, int sig)
{
struct die_args args = { .regs=regs, .str=str, .err=err, .trapnr=trap,.signr=sig };
return notifier_call_chain(&die_chain, val, &args);
}
extern int printk_address(unsigned long address);
extern void die(const char *,struct pt_regs *,long);
extern void __die(const char *,struct pt_regs *,long);
extern void show_registers(struct pt_regs *regs);
extern void dump_pagetable(unsigned long);
extern void oops_begin(void);
extern void oops_end(void);
#endif