/* *  Copyright (C) 1991, 1992  Linus Torvalds *  Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs */#include <linux/kallsyms.h>#include <linux/kprobes.h>#include <linux/uaccess.h>#include <linux/utsname.h>#include <linux/hardirq.h>#include <linux/kdebug.h>#include <linux/module.h>#include <linux/ptrace.h>#include <linux/sched/debug.h>#include <linux/sched/task_stack.h>#include <linux/ftrace.h>#include <linux/kexec.h>#include <linux/bug.h>#include <linux/nmi.h>#include <linux/sysfs.h> #include <asm/stacktrace.h>#include <asm/unwind.h> int panic_on_unrecovered_nmi;int panic_on_io_nmi;unsigned int code_bytes = 64;static int die_counter; bool in_task_stack(unsigned long *stack, struct task_struct *task,		   struct stack_info *info){	unsigned long *begin = task_stack_page(task);	unsigned long *end   = task_stack_page(task) + THREAD_SIZE; 	if (stack < begin || stack >= end)		return false; 	info->type	= STACK_TYPE_TASK;	info->begin	= begin;	info->end	= end;	info->next_sp	= NULL; 	return true;} static void printk_stack_address(unsigned long address, int reliable,				 char *log_lvl){	touch_nmi_watchdog();	printk("%s %s%pB\n", log_lvl, reliable ? "" : "? ", (void *)address);} void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,			unsigned long *stack, char *log_lvl){	struct unwind_state state;	struct stack_info stack_info = {0};	unsigned long visit_mask = 0;	int graph_idx = 0; 	printk("%sCall Trace:\n", log_lvl); 	unwind_start(&state, task, regs, stack);	stack = stack ? : get_stack_pointer(task, regs); 	/*	 * Iterate through the stacks, starting with the current stack pointer.	 * Each stack has a pointer to the next one.	 *	 * x86-64 can have several stacks:	 * - task stack	 * - interrupt stack	 * - HW exception stacks (double fault, nmi, debug, mce)	 *	 * x86-32 can have up to three stacks:	 * - task stack	 * - softirq stack	 * - hardirq stack	 */	for (regs = NULL; stack; stack = PTR_ALIGN(stack_info.next_sp, sizeof(long))) {		const char *stack_name; 		/*		 * If we overflowed the task stack into a guard page, jump back		 * to the bottom of the usable stack.		 */		if (task_stack_page(task) - (void *)stack < PAGE_SIZE)			stack = task_stack_page(task); 		if (get_stack_info(stack, task, &stack_info, &visit_mask))			break; 		stack_name = stack_type_name(stack_info.type);		if (stack_name)			printk("%s <%s>\n", log_lvl, stack_name); 		/*		 * Scan the stack, printing any text addresses we find.  At the		 * same time, follow proper stack frames with the unwinder.		 *		 * Addresses found during the scan which are not reported by		 * the unwinder are considered to be additional clues which are		 * sometimes useful for debugging and are prefixed with '?'.		 * This also serves as a failsafe option in case the unwinder		 * goes off in the weeds.		 */		for (; stack < stack_info.end; stack++) {			unsigned long real_addr;			int reliable = 0;			unsigned long addr = READ_ONCE_NOCHECK(*stack);			unsigned long *ret_addr_p =				unwind_get_return_address_ptr(&state); 			if (!__kernel_text_address(addr))				continue; 			/*			 * Don't print regs->ip again if it was already printed			 * by __show_regs() below.			 */			if (regs && stack == &regs->ip) {				unwind_next_frame(&state);				continue;			} 			if (stack == ret_addr_p)				reliable = 1; 			/*			 * When function graph tracing is enabled for a			 * function, its return address on the stack is			 * replaced with the address of an ftrace handler			 * (return_to_handler).  In that case, before printing			 * the "real" address, we want to print the handler			 * address as an "unreliable" hint that function graph			 * tracing was involved.			 */			real_addr = ftrace_graph_ret_addr(task, &graph_idx,							  addr, stack);			if (real_addr != addr)				printk_stack_address(addr, 0, log_lvl);			printk_stack_address(real_addr, reliable, log_lvl); 			if (!reliable)				continue; 			/*			 * Get the next frame from the unwinder.  No need to			 * check for an error: if anything goes wrong, the rest			 * of the addresses will just be printed as unreliable.			 */			unwind_next_frame(&state); 			/* if the frame has entry regs, print them */			regs = unwind_get_entry_regs(&state);			if (regs)				__show_regs(regs, 0);		} 		if (stack_name)			printk("%s </%s>\n", log_lvl, stack_name);	}} void show_stack(struct task_struct *task, unsigned long *sp){	task = task ? : current; 	/*	 * Stack frames below this one aren't interesting.  Don't show them	 * if we're printing for %current.	 */	if (!sp && task == current)		sp = get_stack_pointer(current, NULL); 	show_trace_log_lvl(task, NULL, sp, KERN_DEFAULT);} void show_stack_regs(struct pt_regs *regs){	show_trace_log_lvl(current, regs, NULL, KERN_DEFAULT);} static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;static int die_owner = -1;static unsigned int die_nest_count; unsigned long oops_begin(void){	int cpu;	unsigned long flags; 	oops_enter(); 	/* racy, but better than risking deadlock. */	raw_local_irq_save(flags);	cpu = smp_processor_id();	if (!arch_spin_trylock(&die_lock)) {		if (cpu == die_owner)			/* nested oops. should stop eventually */;		else			arch_spin_lock(&die_lock);	}	die_nest_count++;	die_owner = cpu;	console_verbose();	bust_spinlocks(1);	return flags;}EXPORT_SYMBOL_GPL(oops_begin);NOKPROBE_SYMBOL(oops_begin); void __noreturn rewind_stack_do_exit(int signr); void oops_end(unsigned long flags, struct pt_regs *regs, int signr){	if (regs && kexec_should_crash(current))		crash_kexec(regs); 	bust_spinlocks(0);	die_owner = -1;	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);	die_nest_count--;	if (!die_nest_count)		/* Nest count reaches zero, release the lock. */		arch_spin_unlock(&die_lock);	raw_local_irq_restore(flags);	oops_exit(); 	if (!signr)		return;	if (in_interrupt())		panic("Fatal exception in interrupt");	if (panic_on_oops)		panic("Fatal exception"); 	/*	 * We're not going to return, but we might be on an IST stack or	 * have very little stack space left.  Rewind the stack and kill	 * the task.	 */	rewind_stack_do_exit(signr);}NOKPROBE_SYMBOL(oops_end); int __die(const char *str, struct pt_regs *regs, long err){#ifdef CONFIG_X86_32	unsigned short ss;	unsigned long sp;#endif	printk(KERN_DEFAULT	       "%s: %04lx [#%d]%s%s%s%s\n", str, err & 0xffff, ++die_counter,	       IS_ENABLED(CONFIG_PREEMPT) ? " PREEMPT"         : "",	       IS_ENABLED(CONFIG_SMP)     ? " SMP"             : "",	       debug_pagealloc_enabled()  ? " DEBUG_PAGEALLOC" : "",	       IS_ENABLED(CONFIG_KASAN)   ? " KASAN"           : ""); 	if (notify_die(DIE_OOPS, str, regs, err,			current->thread.trap_nr, SIGSEGV) == NOTIFY_STOP)		return 1; 	print_modules();	show_regs(regs);#ifdef CONFIG_X86_32	if (user_mode(regs)) {		sp = regs->sp;		ss = regs->ss & 0xffff;	} else {		sp = kernel_stack_pointer(regs);		savesegment(ss, ss);	}	printk(KERN_EMERG "EIP: %pS SS:ESP: %04x:%08lx\n",	       (void *)regs->ip, ss, sp);#else	/* Executive summary in case the oops scrolled away */	printk(KERN_ALERT "RIP: %pS RSP: %016lx\n", (void *)regs->ip, regs->sp);#endif	return 0;}NOKPROBE_SYMBOL(__die); /* * This is gone through when something in the kernel has done something bad * and is about to be terminated: */void die(const char *str, struct pt_regs *regs, long err){	unsigned long flags = oops_begin();	int sig = SIGSEGV; 	if (__die(str, regs, err))		sig = 0;	oops_end(flags, regs, sig);} static int __init code_bytes_setup(char *s){	ssize_t ret;	unsigned long val; 	if (!s)		return -EINVAL; 	ret = kstrtoul(s, 0, &val);	if (ret)		return ret; 	code_bytes = val;	if (code_bytes > 8192)		code_bytes = 8192; 	return 1;}__setup("code_bytes=", code_bytes_setup);