arch/x86/kernel/dumpstack_64.c - linux - Git at Google

 /*
  *  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/hardirq.h>
 #include <linux/kdebug.h>
 #include <linux/module.h>
 #include <linux/ptrace.h>
 #include <linux/kexec.h>
 #include <linux/sysfs.h>
 #include <linux/bug.h>
 #include <linux/nmi.h>

 #include <asm/stacktrace.h>


 #define N_EXCEPTION_STACKS_END \
 		(N_EXCEPTION_STACKS + DEBUG_STKSZ/EXCEPTION_STKSZ - 2)

 static char x86_stack_ids[][8] = {
 		[ DEBUG_STACK-1			]	= "#DB",
 		[ NMI_STACK-1			]	= "NMI",
 		[ DOUBLEFAULT_STACK-1		]	= "#DF",
 		[ MCE_STACK-1			]	= "#MC",
 #if DEBUG_STKSZ > EXCEPTION_STKSZ
 		[ N_EXCEPTION_STACKS ...
 		  N_EXCEPTION_STACKS_END	]	= "#DB[?]"
 #endif
 };

 static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack,
 					 unsigned *usedp, char **idp)
 {
 	unsigned k;

 	/*
 	 * Iterate over all exception stacks, and figure out whether
 	 * 'stack' is in one of them:
 	 */
 	for (k = 0; k < N_EXCEPTION_STACKS; k++) {
 		unsigned long end = per_cpu(orig_ist, cpu).ist[k];
 		/*
 		 * Is 'stack' above this exception frame's end?
 		 * If yes then skip to the next frame.
 		 */
 		if (stack >= end)
 			continue;
 		/*
 		 * Is 'stack' above this exception frame's start address?
 		 * If yes then we found the right frame.
 		 */
 		if (stack >= end - EXCEPTION_STKSZ) {
 			/*
 			 * Make sure we only iterate through an exception
 			 * stack once. If it comes up for the second time
 			 * then there's something wrong going on - just
 			 * break out and return NULL:
 			 */
 			if (*usedp & (1U << k))
 				break;
 			*usedp |= 1U << k;
 			*idp = x86_stack_ids[k];
 			return (unsigned long *)end;
 		}
 		/*
 		 * If this is a debug stack, and if it has a larger size than
 		 * the usual exception stacks, then 'stack' might still
 		 * be within the lower portion of the debug stack:
 		 */
 #if DEBUG_STKSZ > EXCEPTION_STKSZ
 		if (k == DEBUG_STACK - 1 && stack >= end - DEBUG_STKSZ) {
 			unsigned j = N_EXCEPTION_STACKS - 1;

 			/*
 			 * Black magic. A large debug stack is composed of
 			 * multiple exception stack entries, which we
 			 * iterate through now. Dont look:
 			 */
 			do {
 				++j;
 				end -= EXCEPTION_STKSZ;
 				x86_stack_ids[j][4] = '1' +
 						(j - N_EXCEPTION_STACKS);
 			} while (stack < end - EXCEPTION_STKSZ);
 			if (*usedp & (1U << j))
 				break;
 			*usedp |= 1U << j;
 			*idp = x86_stack_ids[j];
 			return (unsigned long *)end;
 		}
 #endif
 	}
 	return NULL;
 }

 static inline int
 in_irq_stack(unsigned long *stack, unsigned long *irq_stack,
 	     unsigned long *irq_stack_end)
 {
 	return (stack >= irq_stack && stack < irq_stack_end);
 }

 static const unsigned long irq_stack_size =
 	(IRQ_STACK_SIZE - 64) / sizeof(unsigned long);

 enum stack_type {
 	STACK_IS_UNKNOWN,
 	STACK_IS_NORMAL,
 	STACK_IS_EXCEPTION,
 	STACK_IS_IRQ,
 };

 static enum stack_type
 analyze_stack(int cpu, struct task_struct *task, unsigned long *stack,
 	      unsigned long **stack_end, unsigned long *irq_stack,
 	      unsigned *used, char **id)
 {
 	unsigned long addr;

 	addr = ((unsigned long)stack & (~(THREAD_SIZE - 1)));
 	if ((unsigned long)task_stack_page(task) == addr)
 		return STACK_IS_NORMAL;

 	*stack_end = in_exception_stack(cpu, (unsigned long)stack,
 					used, id);
 	if (*stack_end)
 		return STACK_IS_EXCEPTION;

 	if (!irq_stack)
 		return STACK_IS_NORMAL;

 	*stack_end = irq_stack;
 	irq_stack = irq_stack - irq_stack_size;

 	if (in_irq_stack(stack, irq_stack, *stack_end))
 		return STACK_IS_IRQ;

 	return STACK_IS_UNKNOWN;
 }

 /*
  * x86-64 can have up to three kernel stacks:
  * process stack
  * interrupt stack
  * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
  */

 void dump_trace(struct task_struct *task, struct pt_regs *regs,
 		unsigned long *stack, unsigned long bp,
 		const struct stacktrace_ops *ops, void *data)
 {
 	const unsigned cpu = get_cpu();
 	struct thread_info *tinfo;
 	unsigned long *irq_stack = (unsigned long *)per_cpu(irq_stack_ptr, cpu);
 	unsigned long dummy;
 	unsigned used = 0;
 	int graph = 0;
 	int done = 0;

 	if (!task)
 		task = current;

 	if (!stack) {
 		if (regs)
 			stack = (unsigned long *)regs->sp;
 		else if (task != current)
 			stack = (unsigned long *)task->thread.sp;
 		else
 			stack = &dummy;
 	}

 	if (!bp)
 		bp = stack_frame(task, regs);
 	/*
 	 * Print function call entries in all stacks, starting at the
 	 * current stack address. If the stacks consist of nested
 	 * exceptions
 	 */
 	tinfo = task_thread_info(task);
 	while (!done) {
 		unsigned long *stack_end;
 		enum stack_type stype;
 		char *id;

 		stype = analyze_stack(cpu, task, stack, &stack_end,
 				      irq_stack, &used, &id);

 		/* Default finish unless specified to continue */
 		done = 1;

 		switch (stype) {

 		/* Break out early if we are on the thread stack */
 		case STACK_IS_NORMAL:
 			break;

 		case STACK_IS_EXCEPTION:

 			if (ops->stack(data, id) < 0)
 				break;

 			bp = ops->walk_stack(tinfo, stack, bp, ops,
 					     data, stack_end, &graph);
 			ops->stack(data, "<EOE>");
 			/*
 			 * We link to the next stack via the
 			 * second-to-last pointer (index -2 to end) in the
 			 * exception stack:
 			 */
 			stack = (unsigned long *) stack_end[-2];
 			done = 0;
 			break;

 		case STACK_IS_IRQ:

 			if (ops->stack(data, "IRQ") < 0)
 				break;
 			bp = ops->walk_stack(tinfo, stack, bp,
 				     ops, data, stack_end, &graph);
 			/*
 			 * We link to the next stack (which would be
 			 * the process stack normally) the last
 			 * pointer (index -1 to end) in the IRQ stack:
 			 */
 			stack = (unsigned long *) (stack_end[-1]);
 			irq_stack = NULL;
 			ops->stack(data, "EOI");
 			done = 0;
 			break;

 		case STACK_IS_UNKNOWN:
 			ops->stack(data, "UNK");
 			break;
 		}
 	}

 	/*
 	 * This handles the process stack:
 	 */
 	bp = ops->walk_stack(tinfo, stack, bp, ops, data, NULL, &graph);
 	put_cpu();
 }
 EXPORT_SYMBOL(dump_trace);

 void
 show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
 		   unsigned long *sp, unsigned long bp, char *log_lvl)
 {
 	unsigned long *irq_stack_end;
 	unsigned long *irq_stack;
 	unsigned long *stack;
 	int cpu;
 	int i;

 	preempt_disable();
 	cpu = smp_processor_id();

 	irq_stack_end	= (unsigned long *)(per_cpu(irq_stack_ptr, cpu));
 	irq_stack	= (unsigned long *)(per_cpu(irq_stack_ptr, cpu) - IRQ_STACK_SIZE);

 	/*
 	 * Debugging aid: "show_stack(NULL, NULL);" prints the
 	 * back trace for this cpu:
 	 */
 	if (sp == NULL) {
 		if (task)
 			sp = (unsigned long *)task->thread.sp;
 		else
 			sp = (unsigned long *)&sp;
 	}

 	stack = sp;
 	for (i = 0; i < kstack_depth_to_print; i++) {
 		if (stack >= irq_stack && stack <= irq_stack_end) {
 			if (stack == irq_stack_end) {
 				stack = (unsigned long *) (irq_stack_end[-1]);
 				pr_cont(" <EOI> ");
 			}
 		} else {
 		if (kstack_end(stack))
 			break;
 		}
 		if ((i % STACKSLOTS_PER_LINE) == 0) {
 			if (i != 0)
 				pr_cont("\n");
 			printk("%s %016lx", log_lvl, *stack++);
 		} else
 			pr_cont(" %016lx", *stack++);
 		touch_nmi_watchdog();
 	}
 	preempt_enable();

 	pr_cont("\n");
 	show_trace_log_lvl(task, regs, sp, bp, log_lvl);
 }

 void show_regs(struct pt_regs *regs)
 {
 	int i;
 	unsigned long sp;

 	sp = regs->sp;
 	show_regs_print_info(KERN_DEFAULT);
 	__show_regs(regs, 1);

 	/*
 	 * When in-kernel, we also print out the stack and code at the
 	 * time of the fault..
 	 */
 	if (!user_mode(regs)) {
 		unsigned int code_prologue = code_bytes * 43 / 64;
 		unsigned int code_len = code_bytes;
 		unsigned char c;
 		u8 *ip;

 		printk(KERN_DEFAULT "Stack:\n");
 		show_stack_log_lvl(NULL, regs, (unsigned long *)sp,
 				   0, KERN_DEFAULT);

 		printk(KERN_DEFAULT "Code: ");

 		ip = (u8 *)regs->ip - code_prologue;
 		if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
 			/* try starting at IP */
 			ip = (u8 *)regs->ip;
 			code_len = code_len - code_prologue + 1;
 		}
 		for (i = 0; i < code_len; i++, ip++) {
 			if (ip < (u8 *)PAGE_OFFSET ||
 					probe_kernel_address(ip, c)) {
 				pr_cont(" Bad RIP value.");
 				break;
 			}
 			if (ip == (u8 *)regs->ip)
 				pr_cont("<%02x> ", c);
 			else
 				pr_cont("%02x ", c);
 		}
 	}
 	pr_cont("\n");
 }

 int is_valid_bugaddr(unsigned long ip)
 {
 	unsigned short ud2;

 	if (__copy_from_user(&ud2, (const void __user *) ip, sizeof(ud2)))
 		return 0;

 	return ud2 == 0x0b0f;
 }
	/*
	* 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/hardirq.h>
	#include <linux/kdebug.h>
	#include <linux/module.h>
	#include <linux/ptrace.h>
	#include <linux/kexec.h>
	#include <linux/sysfs.h>
	#include <linux/bug.h>
	#include <linux/nmi.h>

	#include <asm/stacktrace.h>


	#define N_EXCEPTION_STACKS_END \
	(N_EXCEPTION_STACKS + DEBUG_STKSZ/EXCEPTION_STKSZ - 2)

	static char x86_stack_ids[][8] = {
	[ DEBUG_STACK-1 ] = "#DB",
	[ NMI_STACK-1 ] = "NMI",
	[ DOUBLEFAULT_STACK-1 ] = "#DF",
	[ MCE_STACK-1 ] = "#MC",
	#if DEBUG_STKSZ > EXCEPTION_STKSZ
	[ N_EXCEPTION_STACKS ...
	N_EXCEPTION_STACKS_END ] = "#DB[?]"
	#endif
	};

	static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack,
	unsigned usedp, char *idp)
	{
	unsigned k;

	/*
	* Iterate over all exception stacks, and figure out whether
	* 'stack' is in one of them:
	*/
	for (k = 0; k < N_EXCEPTION_STACKS; k++) {
	unsigned long end = per_cpu(orig_ist, cpu).ist[k];
	/*
	* Is 'stack' above this exception frame's end?
	* If yes then skip to the next frame.
	*/
	if (stack >= end)
	continue;
	/*
	* Is 'stack' above this exception frame's start address?
	* If yes then we found the right frame.
	*/
	if (stack >= end - EXCEPTION_STKSZ) {
	/*
	* Make sure we only iterate through an exception
	* stack once. If it comes up for the second time
	* then there's something wrong going on - just
	* break out and return NULL:
	*/
	if (*usedp & (1U << k))
	break;
	*usedp \|= 1U << k;
	*idp = x86_stack_ids[k];
	return (unsigned long *)end;
	}
	/*
	* If this is a debug stack, and if it has a larger size than
	* the usual exception stacks, then 'stack' might still
	* be within the lower portion of the debug stack:
	*/
	#if DEBUG_STKSZ > EXCEPTION_STKSZ
	if (k == DEBUG_STACK - 1 && stack >= end - DEBUG_STKSZ) {
	unsigned j = N_EXCEPTION_STACKS - 1;

	/*
	* Black magic. A large debug stack is composed of
	* multiple exception stack entries, which we
	* iterate through now. Dont look:
	*/
	do {
	++j;
	end -= EXCEPTION_STKSZ;
	x86_stack_ids[j][4] = '1' +
	(j - N_EXCEPTION_STACKS);
	} while (stack < end - EXCEPTION_STKSZ);
	if (*usedp & (1U << j))
	break;
	*usedp \|= 1U << j;
	*idp = x86_stack_ids[j];
	return (unsigned long *)end;
	}
	#endif
	}
	return NULL;
	}

	static inline int
	in_irq_stack(unsigned long stack, unsigned long irq_stack,
	unsigned long *irq_stack_end)
	{
	return (stack >= irq_stack && stack < irq_stack_end);
	}

	static const unsigned long irq_stack_size =
	(IRQ_STACK_SIZE - 64) / sizeof(unsigned long);

	enum stack_type {
	STACK_IS_UNKNOWN,
	STACK_IS_NORMAL,
	STACK_IS_EXCEPTION,
	STACK_IS_IRQ,
	};

	static enum stack_type
	analyze_stack(int cpu, struct task_struct task, unsigned long stack,
	unsigned long *stack_end, unsigned long irq_stack,
	unsigned used, char *id)
	{
	unsigned long addr;

	addr = ((unsigned long)stack & (~(THREAD_SIZE - 1)));
	if ((unsigned long)task_stack_page(task) == addr)
	return STACK_IS_NORMAL;

	*stack_end = in_exception_stack(cpu, (unsigned long)stack,
	used, id);
	if (*stack_end)
	return STACK_IS_EXCEPTION;

	if (!irq_stack)
	return STACK_IS_NORMAL;

	*stack_end = irq_stack;
	irq_stack = irq_stack - irq_stack_size;

	if (in_irq_stack(stack, irq_stack, *stack_end))
	return STACK_IS_IRQ;

	return STACK_IS_UNKNOWN;
	}

	/*
	* x86-64 can have up to three kernel stacks:
	* process stack
	* interrupt stack
	* severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
	*/

	void dump_trace(struct task_struct task, struct pt_regs regs,
	unsigned long *stack, unsigned long bp,
	const struct stacktrace_ops ops, void data)
	{
	const unsigned cpu = get_cpu();
	struct thread_info *tinfo;
	unsigned long irq_stack = (unsigned long )per_cpu(irq_stack_ptr, cpu);
	unsigned long dummy;
	unsigned used = 0;
	int graph = 0;
	int done = 0;

	if (!task)
	task = current;

	if (!stack) {
	if (regs)
	stack = (unsigned long *)regs->sp;
	else if (task != current)
	stack = (unsigned long *)task->thread.sp;
	else
	stack = &dummy;
	}

	if (!bp)
	bp = stack_frame(task, regs);
	/*
	* Print function call entries in all stacks, starting at the
	* current stack address. If the stacks consist of nested
	* exceptions
	*/
	tinfo = task_thread_info(task);
	while (!done) {
	unsigned long *stack_end;
	enum stack_type stype;
	char *id;

	stype = analyze_stack(cpu, task, stack, &stack_end,
	irq_stack, &used, &id);

	/* Default finish unless specified to continue */
	done = 1;

	switch (stype) {

	/* Break out early if we are on the thread stack */
	case STACK_IS_NORMAL:
	break;

	case STACK_IS_EXCEPTION:

	if (ops->stack(data, id) < 0)
	break;

	bp = ops->walk_stack(tinfo, stack, bp, ops,
	data, stack_end, &graph);
	ops->stack(data, "<EOE>");
	/*
	* We link to the next stack via the
	* second-to-last pointer (index -2 to end) in the
	* exception stack:
	*/
	stack = (unsigned long *) stack_end[-2];
	done = 0;
	break;

	case STACK_IS_IRQ:

	if (ops->stack(data, "IRQ") < 0)
	break;
	bp = ops->walk_stack(tinfo, stack, bp,
	ops, data, stack_end, &graph);
	/*
	* We link to the next stack (which would be
	* the process stack normally) the last
	* pointer (index -1 to end) in the IRQ stack:
	*/
	stack = (unsigned long *) (stack_end[-1]);
	irq_stack = NULL;
	ops->stack(data, "EOI");
	done = 0;
	break;

	case STACK_IS_UNKNOWN:
	ops->stack(data, "UNK");
	break;
	}
	}

	/*
	* This handles the process stack:
	*/
	bp = ops->walk_stack(tinfo, stack, bp, ops, data, NULL, &graph);
	put_cpu();
	}
	EXPORT_SYMBOL(dump_trace);

	void
	show_stack_log_lvl(struct task_struct task, struct pt_regs regs,
	unsigned long sp, unsigned long bp, char log_lvl)
	{
	unsigned long *irq_stack_end;
	unsigned long *irq_stack;
	unsigned long *stack;
	int cpu;
	int i;

	preempt_disable();
	cpu = smp_processor_id();

	irq_stack_end = (unsigned long *)(per_cpu(irq_stack_ptr, cpu));
	irq_stack = (unsigned long *)(per_cpu(irq_stack_ptr, cpu) - IRQ_STACK_SIZE);

	/*
	* Debugging aid: "show_stack(NULL, NULL);" prints the
	* back trace for this cpu:
	*/
	if (sp == NULL) {
	if (task)
	sp = (unsigned long *)task->thread.sp;
	else
	sp = (unsigned long *)&sp;
	}

	stack = sp;
	for (i = 0; i < kstack_depth_to_print; i++) {
	if (stack >= irq_stack && stack <= irq_stack_end) {
	if (stack == irq_stack_end) {
	stack = (unsigned long *) (irq_stack_end[-1]);
	pr_cont(" <EOI> ");
	}
	} else {
	if (kstack_end(stack))
	break;
	}
	if ((i % STACKSLOTS_PER_LINE) == 0) {
	if (i != 0)
	pr_cont("\n");
	printk("%s %016lx", log_lvl, *stack++);
	} else
	pr_cont(" %016lx", *stack++);
	touch_nmi_watchdog();
	}
	preempt_enable();

	pr_cont("\n");
	show_trace_log_lvl(task, regs, sp, bp, log_lvl);
	}

	void show_regs(struct pt_regs *regs)
	{
	int i;
	unsigned long sp;

	sp = regs->sp;
	show_regs_print_info(KERN_DEFAULT);
	__show_regs(regs, 1);

	/*
	* When in-kernel, we also print out the stack and code at the
	* time of the fault..
	*/
	if (!user_mode(regs)) {
	unsigned int code_prologue = code_bytes * 43 / 64;
	unsigned int code_len = code_bytes;
	unsigned char c;
	u8 *ip;

	printk(KERN_DEFAULT "Stack:\n");
	show_stack_log_lvl(NULL, regs, (unsigned long *)sp,
	0, KERN_DEFAULT);

	printk(KERN_DEFAULT "Code: ");

	ip = (u8 *)regs->ip - code_prologue;
	if (ip < (u8 *)PAGE_OFFSET \|\| probe_kernel_address(ip, c)) {
	/* try starting at IP */
	ip = (u8 *)regs->ip;
	code_len = code_len - code_prologue + 1;
	}
	for (i = 0; i < code_len; i++, ip++) {
	if (ip < (u8 *)PAGE_OFFSET \|\|
	probe_kernel_address(ip, c)) {
	pr_cont(" Bad RIP value.");
	break;
	}
	if (ip == (u8 *)regs->ip)
	pr_cont("<%02x> ", c);
	else
	pr_cont("%02x ", c);
	}
	}
	pr_cont("\n");
	}

	int is_valid_bugaddr(unsigned long ip)
	{
	unsigned short ud2;

	if (__copy_from_user(&ud2, (const void __user *) ip, sizeof(ud2)))
	return 0;

	return ud2 == 0x0b0f;
	}