/* * Stack trace management functions * *  Copyright (C) 2006-2009 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> */#include <linux/sched.h>#include <linux/stacktrace.h>#include <linux/module.h>#include <linux/uaccess.h>#include <asm/stacktrace.h> static int save_stack_stack(void *data, char *name){	return 0;} static void__save_stack_address(void *data, unsigned long addr, bool reliable, bool nosched){	struct stack_trace *trace = data;#ifdef CONFIG_FRAME_POINTER	if (!reliable)		return;#endif	if (nosched && in_sched_functions(addr))		return;	if (trace->skip > 0) {		trace->skip--;		return;	}	if (trace->nr_entries < trace->max_entries)		trace->entries[trace->nr_entries++] = addr;} static void save_stack_address(void *data, unsigned long addr, int reliable){	return __save_stack_address(data, addr, reliable, false);} static voidsave_stack_address_nosched(void *data, unsigned long addr, int reliable){	return __save_stack_address(data, addr, reliable, true);} static const struct stacktrace_ops save_stack_ops = {	.stack		= save_stack_stack,	.address	= save_stack_address,	.walk_stack	= print_context_stack,}; static const struct stacktrace_ops save_stack_ops_nosched = {	.stack		= save_stack_stack,	.address	= save_stack_address_nosched,	.walk_stack	= print_context_stack,}; /* * Save stack-backtrace addresses into a stack_trace buffer. */void save_stack_trace(struct stack_trace *trace){	dump_trace(current, NULL, NULL, 0, &save_stack_ops, trace);	if (trace->nr_entries < trace->max_entries)		trace->entries[trace->nr_entries++] = ULONG_MAX;}EXPORT_SYMBOL_GPL(save_stack_trace); void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace){	dump_trace(current, regs, NULL, 0, &save_stack_ops, trace);	if (trace->nr_entries < trace->max_entries)		trace->entries[trace->nr_entries++] = ULONG_MAX;} void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace){	dump_trace(tsk, NULL, NULL, 0, &save_stack_ops_nosched, trace);	if (trace->nr_entries < trace->max_entries)		trace->entries[trace->nr_entries++] = ULONG_MAX;}EXPORT_SYMBOL_GPL(save_stack_trace_tsk); /* Userspace stacktrace - based on kernel/trace/trace_sysprof.c */ struct stack_frame_user {	const void __user	*next_fp;	unsigned long		ret_addr;}; static intcopy_stack_frame(const void __user *fp, struct stack_frame_user *frame){	int ret; 	if (!access_ok(VERIFY_READ, fp, sizeof(*frame)))		return 0; 	ret = 1;	pagefault_disable();	if (__copy_from_user_inatomic(frame, fp, sizeof(*frame)))		ret = 0;	pagefault_enable(); 	return ret;} static inline void __save_stack_trace_user(struct stack_trace *trace){	const struct pt_regs *regs = task_pt_regs(current);	const void __user *fp = (const void __user *)regs->bp; 	if (trace->nr_entries < trace->max_entries)		trace->entries[trace->nr_entries++] = regs->ip; 	while (trace->nr_entries < trace->max_entries) {		struct stack_frame_user frame; 		frame.next_fp = NULL;		frame.ret_addr = 0;		if (!copy_stack_frame(fp, &frame))			break;		if ((unsigned long)fp < regs->sp)			break;		if (frame.ret_addr) {			trace->entries[trace->nr_entries++] =				frame.ret_addr;		}		if (fp == frame.next_fp)			break;		fp = frame.next_fp;	}} void save_stack_trace_user(struct stack_trace *trace){	/*	 * Trace user stack if we are not a kernel thread	 */	if (current->mm) {		__save_stack_trace_user(trace);	}	if (trace->nr_entries < trace->max_entries)		trace->entries[trace->nr_entries++] = ULONG_MAX;}