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daeeafecf0
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>
53 lines
1.2 KiB
C
53 lines
1.2 KiB
C
#ifndef _X86_64_KDEBUG_H
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#define _X86_64_KDEBUG_H 1
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#include <linux/notifier.h>
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struct pt_regs;
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struct die_args {
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struct pt_regs *regs;
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const char *str;
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long err;
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int trapnr;
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int signr;
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};
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/* Note - you should never unregister because that can race with NMIs.
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If you really want to do it first unregister - then synchronize_kernel - then free.
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*/
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int register_die_notifier(struct notifier_block *nb);
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extern struct notifier_block *die_chain;
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/* Grossly misnamed. */
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enum die_val {
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DIE_OOPS = 1,
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DIE_INT3,
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DIE_DEBUG,
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DIE_PANIC,
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DIE_NMI,
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DIE_DIE,
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DIE_NMIWATCHDOG,
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DIE_KERNELDEBUG,
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DIE_TRAP,
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DIE_GPF,
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DIE_CALL,
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DIE_NMI_IPI,
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DIE_PAGE_FAULT,
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};
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static inline int notify_die(enum die_val val,char *str,struct pt_regs *regs,long err,int trap, int sig)
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{
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struct die_args args = { .regs=regs, .str=str, .err=err, .trapnr=trap,.signr=sig };
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return notifier_call_chain(&die_chain, val, &args);
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}
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extern int printk_address(unsigned long address);
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extern void die(const char *,struct pt_regs *,long);
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extern void __die(const char *,struct pt_regs *,long);
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extern void show_registers(struct pt_regs *regs);
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extern void dump_pagetable(unsigned long);
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extern void oops_begin(void);
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extern void oops_end(void);
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#endif
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