/* * Stack trace management functions * *  Copyright (C) 2006-2009 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> */#include <linux/sched.h>#include <linux/sched/debug.h>#include <linux/sched/task_stack.h>#include <linux/stacktrace.h>#include <linux/export.h>#include <linux/uaccess.h>#include <asm/stacktrace.h>#include <asm/unwind.h> void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,		     struct task_struct *task, struct pt_regs *regs){	struct unwind_state state;	unsigned long addr; 	if (regs && !consume_entry(cookie, regs->ip))		return; 	for (unwind_start(&state, task, regs, NULL); !unwind_done(&state);	     unwind_next_frame(&state)) {		addr = unwind_get_return_address(&state);		if (!addr || !consume_entry(cookie, addr))			break;	}} int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry,			     void *cookie, struct task_struct *task){	struct unwind_state state;	struct pt_regs *regs;	unsigned long addr; 	for (unwind_start(&state, task, NULL, NULL);	     !unwind_done(&state) && !unwind_error(&state);	     unwind_next_frame(&state)) { 		regs = unwind_get_entry_regs(&state, NULL);		if (regs) {			/* Success path for user tasks */			if (user_mode(regs))				return 0; 			/*			 * Kernel mode registers on the stack indicate an			 * in-kernel interrupt or exception (e.g., preemption			 * or a page fault), which can make frame pointers			 * unreliable.			 */			if (IS_ENABLED(CONFIG_FRAME_POINTER))				return -EINVAL;		} 		addr = unwind_get_return_address(&state); 		/*		 * A NULL or invalid return address probably means there's some		 * generated code which __kernel_text_address() doesn't know		 * about.		 */		if (!addr)			return -EINVAL; 		if (!consume_entry(cookie, addr))			return -EINVAL;	} 	/* Check for stack corruption */	if (unwind_error(&state))		return -EINVAL; 	return 0;} /* 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 struct stack_frame_user __user *fp,		 struct stack_frame_user *frame){	int ret; 	if (!__access_ok(fp, sizeof(*frame)))		return 0; 	ret = 1;	pagefault_disable();	if (__get_user(frame->next_fp, &fp->next_fp) ||	    __get_user(frame->ret_addr, &fp->ret_addr))		ret = 0;	pagefault_enable(); 	return ret;} void arch_stack_walk_user(stack_trace_consume_fn consume_entry, void *cookie,			  const struct pt_regs *regs){	const void __user *fp = (const void __user *)regs->bp; 	if (!consume_entry(cookie, regs->ip))		return; 	while (1) {		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)			break;		if (!consume_entry(cookie, frame.ret_addr))			break;		fp = frame.next_fp;	}}