Commit 737a460f authored by Jason Wessel's avatar Jason Wessel Committed by Ingo Molnar
Browse files

kgdb: fix several kgdb regressions 



kgdb core fixes:
- Check to see that mm->mmap_cache is not null before calling
  flush_cache_range(), else on arch=ARM it will cause a fatal
  fault.

- Breakpoints should only be restored if they are in the BP_ACTIVE
  state.

- Fix a typo in comments to "kgdb_register_io_module"

x86 kgdb fixes:
- Fix the x86 arch handler such that on a kill or detach that the
  appropriate cleanup on the single stepping flags gets run.

- Add in the DIE_NMIWATCHDOG call for x86_64

- Touch the nmi watchdog before returning the system to normal
  operation after performing any kind of kgdb operation, else
  the possibility exists to trigger the watchdog.

Signed-off-by: default avatarJason Wessel <jason.wessel@windriver.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 84b5ae15

arch/x86/kernel/kgdb.c

+4 −0
Original line number Diff line number Diff line
@@ -370,6 +370,8 @@ int kgdb_arch_handle_exception(int e_vector, int signo, int err_code, 
		ptr = &remcomInBuffer[1];

		if (kgdb_hex2long(&ptr, &addr))

			linux_regs->ip = addr;

	case 'D':

	case 'k':

		newPC = linux_regs->ip;



		/* clear the trace bit */
@@ -480,6 +482,8 @@ static int __kgdb_notify(struct die_args *args, unsigned long cmd) 
	if (kgdb_handle_exception(args->trapnr, args->signr, args->err, regs))

		return NOTIFY_DONE;



	/* Must touch watchdog before return to normal operation */

	touch_nmi_watchdog();

	return NOTIFY_STOP;

}

arch/x86/kernel/traps_64.c

+6 −1
Original line number Diff line number Diff line
@@ -600,8 +600,13 @@ void die(const char * str, struct pt_regs * regs, long err) 


void __kprobes die_nmi(char *str, struct pt_regs *regs, int do_panic)

{

	unsigned long flags = oops_begin();

	unsigned long flags;



	if (notify_die(DIE_NMIWATCHDOG, str, regs, 0, 2, SIGINT) ==

	    NOTIFY_STOP)

		return;



	flags = oops_begin();

	/*

	 * We are in trouble anyway, lets at least try

	 * to get a message out.

kernel/kgdb.c

+8 −6
Original line number Diff line number Diff line
@@ -600,7 +600,7 @@ static void kgdb_flush_swbreak_addr(unsigned long addr) 
	if (!CACHE_FLUSH_IS_SAFE)

		return;



	if (current->mm) {

	if (current->mm && current->mm->mmap_cache) {

		flush_cache_range(current->mm->mmap_cache,

				  addr, addr + BREAK_INSTR_SIZE);

	} else {
@@ -729,14 +729,16 @@ int remove_all_break(void) 


	/* Clear memory breakpoints. */

	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {

		if (kgdb_break[i].state != BP_SET)

			continue;

		if (kgdb_break[i].state != BP_ACTIVE)

			goto setundefined;

		addr = kgdb_break[i].bpt_addr;

		error = kgdb_arch_remove_breakpoint(addr,

				kgdb_break[i].saved_instr);

		if (error)

			return error;

		kgdb_break[i].state = BP_REMOVED;

			printk(KERN_ERR "KGDB: breakpoint remove failed: %lx\n",

			   addr);

setundefined:

		kgdb_break[i].state = BP_UNDEFINED;

	}



	/* Clear hardware breakpoints. */
@@ -1605,7 +1607,7 @@ static void kgdb_initial_breakpoint(void) 
}



/**

 *	kkgdb_register_io_module - register KGDB IO module

 *	kgdb_register_io_module - register KGDB IO module

 *	@new_kgdb_io_ops: the io ops vector

 *

 *	Register it with the KGDB core.

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