Commit b351d164 authored by Peter Zijlstra's avatar Peter Zijlstra
Browse files

lockdep: syscall exit check 



Provide a check to validate that we do not hold any locks when switching
back to user-space.

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent e4564f79

include/linux/lockdep.h

+2 −0
Original line number Diff line number Diff line
@@ -238,6 +238,7 @@ extern void lockdep_info(void); 
extern void lockdep_reset(void);

extern void lockdep_reset_lock(struct lockdep_map *lock);

extern void lockdep_free_key_range(void *start, unsigned long size);

extern void lockdep_sys_exit(void);



extern void lockdep_off(void);

extern void lockdep_on(void);
@@ -317,6 +318,7 @@ static inline void lockdep_on(void) 
# define INIT_LOCKDEP

# define lockdep_reset()		do { debug_locks = 1; } while (0)

# define lockdep_free_key_range(start, size)	do { } while (0)

# define lockdep_sys_exit() 			do { } while (0)

/*

 * The class key takes no space if lockdep is disabled:

 */

kernel/lockdep.c

+16 −0
Original line number Diff line number Diff line
@@ -3199,3 +3199,19 @@ void debug_show_held_locks(struct task_struct *task) 
}



EXPORT_SYMBOL_GPL(debug_show_held_locks);



void lockdep_sys_exit(void)

{

	struct task_struct *curr = current;



	if (unlikely(curr->lockdep_depth)) {

		if (!debug_locks_off())

			return;

		printk("\n================================================\n");

		printk(  "[ BUG: lock held when returning to user space! ]\n");

		printk(  "------------------------------------------------\n");

		printk("%s/%d is leaving the kernel with locks still held!\n",

				curr->comm, curr->pid);

		lockdep_print_held_locks(curr);

	}

}