text: #ifndef __LINUX_STACKTRACE_H
  #define __LINUX_STACKTRACE_H
  
  #include <linux/types.h>
  
  struct task_struct;
  struct pt_regs;
  
  #ifdef CONFIG_STACKTRACE
  struct task_struct;
  
  struct stack_trace {
  	unsigned int nr_entries, max_entries;
  	unsigned long *entries;
  	int skip;	/* input argument: How many entries to skip */
  };
  
  extern void save_stack_trace(struct stack_trace *trace);
  extern void save_stack_trace_regs(struct pt_regs *regs,
  				  struct stack_trace *trace);
  extern void save_stack_trace_tsk(struct task_struct *tsk,
  				struct stack_trace *trace);
  
  extern void print_stack_trace(struct stack_trace *trace, int spaces);
  extern int snprint_stack_trace(char *buf, size_t size,
  			struct stack_trace *trace, int spaces);
  
  #ifdef CONFIG_USER_STACKTRACE_SUPPORT
  extern void save_stack_trace_user(struct stack_trace *trace);
  #else
  # define save_stack_trace_user(trace)              do { } while (0)
  #endif
  
  #else
  # define save_stack_trace(trace)			do { } while (0)
  # define save_stack_trace_tsk(tsk, trace)		do { } while (0)
  # define save_stack_trace_user(trace)			do { } while (0)
  # define print_stack_trace(trace, spaces)		do { } while (0)
  # define snprint_stack_trace(buf, size, trace, spaces)	do { } while (0)
  #endif
  
  #endif
  