// SPDX-License-Identifier: GPL-2.0-only/* * kernel/stacktrace.c * * Stack trace management functions * *  Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> */#include <linux/sched/task_stack.h>#include <linux/sched/debug.h>#include <linux/sched.h>#include <linux/kernel.h>#include <linux/export.h>#include <linux/kallsyms.h>#include <linux/stacktrace.h>#include <linux/interrupt.h> /** * stack_trace_print - Print the entries in the stack trace * @entries:	Pointer to storage array * @nr_entries:	Number of entries in the storage array * @spaces:	Number of leading spaces to print */void stack_trace_print(const unsigned long *entries, unsigned int nr_entries,		       int spaces){	unsigned int i; 	if (WARN_ON(!entries))		return; 	for (i = 0; i < nr_entries; i++)		printk("%*c%pS\n", 1 + spaces, ' ', (void *)entries[i]);}EXPORT_SYMBOL_GPL(stack_trace_print); /** * stack_trace_snprint - Print the entries in the stack trace into a buffer * @buf:	Pointer to the print buffer * @size:	Size of the print buffer * @entries:	Pointer to storage array * @nr_entries:	Number of entries in the storage array * @spaces:	Number of leading spaces to print * * Return: Number of bytes printed. */int stack_trace_snprint(char *buf, size_t size, const unsigned long *entries,			unsigned int nr_entries, int spaces){	unsigned int generated, i, total = 0; 	if (WARN_ON(!entries))		return 0; 	for (i = 0; i < nr_entries && size; i++) {		generated = snprintf(buf, size, "%*c%pS\n", 1 + spaces, ' ',				     (void *)entries[i]); 		total += generated;		if (generated >= size) {			buf += size;			size = 0;		} else {			buf += generated;			size -= generated;		}	} 	return total;}EXPORT_SYMBOL_GPL(stack_trace_snprint); #ifdef CONFIG_ARCH_STACKWALK struct stacktrace_cookie {	unsigned long	*store;	unsigned int	size;	unsigned int	skip;	unsigned int	len;}; static bool stack_trace_consume_entry(void *cookie, unsigned long addr){	struct stacktrace_cookie *c = cookie; 	if (c->len >= c->size)		return false; 	if (c->skip > 0) {		c->skip--;		return true;	}	c->store[c->len++] = addr;	return c->len < c->size;} static bool stack_trace_consume_entry_nosched(void *cookie, unsigned long addr){	if (in_sched_functions(addr))		return true;	return stack_trace_consume_entry(cookie, addr);} /** * stack_trace_save - Save a stack trace into a storage array * @store:	Pointer to storage array * @size:	Size of the storage array * @skipnr:	Number of entries to skip at the start of the stack trace * * Return: Number of trace entries stored. */unsigned int stack_trace_save(unsigned long *store, unsigned int size,			      unsigned int skipnr){	stack_trace_consume_fn consume_entry = stack_trace_consume_entry;	struct stacktrace_cookie c = {		.store	= store,		.size	= size,		.skip	= skipnr + 1,	}; 	arch_stack_walk(consume_entry, &c, current, NULL);	return c.len;}EXPORT_SYMBOL_GPL(stack_trace_save); /** * stack_trace_save_tsk - Save a task stack trace into a storage array * @task:	The task to examine * @store:	Pointer to storage array * @size:	Size of the storage array * @skipnr:	Number of entries to skip at the start of the stack trace * * Return: Number of trace entries stored. */unsigned int stack_trace_save_tsk(struct task_struct *tsk, unsigned long *store,				  unsigned int size, unsigned int skipnr){	stack_trace_consume_fn consume_entry = stack_trace_consume_entry_nosched;	struct stacktrace_cookie c = {		.store	= store,		.size	= size,		/* skip this function if they are tracing us */		.skip	= skipnr + (current == tsk),	}; 	if (!try_get_task_stack(tsk))		return 0; 	arch_stack_walk(consume_entry, &c, tsk, NULL);	put_task_stack(tsk);	return c.len;} /** * stack_trace_save_regs - Save a stack trace based on pt_regs into a storage array * @regs:	Pointer to pt_regs to examine * @store:	Pointer to storage array * @size:	Size of the storage array * @skipnr:	Number of entries to skip at the start of the stack trace * * Return: Number of trace entries stored. */unsigned int stack_trace_save_regs(struct pt_regs *regs, unsigned long *store,				   unsigned int size, unsigned int skipnr){	stack_trace_consume_fn consume_entry = stack_trace_consume_entry;	struct stacktrace_cookie c = {		.store	= store,		.size	= size,		.skip	= skipnr,	}; 	arch_stack_walk(consume_entry, &c, current, regs);	return c.len;} #ifdef CONFIG_HAVE_RELIABLE_STACKTRACE/** * stack_trace_save_tsk_reliable - Save task stack with verification * @tsk:	Pointer to the task to examine * @store:	Pointer to storage array * @size:	Size of the storage array * * Return:	An error if it detects any unreliable features of the *		stack. Otherwise it guarantees that the stack trace is *		reliable and returns the number of entries stored. * * If the task is not 'current', the caller *must* ensure the task is inactive. */int stack_trace_save_tsk_reliable(struct task_struct *tsk, unsigned long *store,				  unsigned int size){	stack_trace_consume_fn consume_entry = stack_trace_consume_entry;	struct stacktrace_cookie c = {		.store	= store,		.size	= size,	};	int ret; 	/*	 * If the task doesn't have a stack (e.g., a zombie), the stack is	 * "reliably" empty.	 */	if (!try_get_task_stack(tsk))		return 0; 	ret = arch_stack_walk_reliable(consume_entry, &c, tsk);	put_task_stack(tsk);	return ret ? ret : c.len;}#endif #ifdef CONFIG_USER_STACKTRACE_SUPPORT/** * stack_trace_save_user - Save a user space stack trace into a storage array * @store:	Pointer to storage array * @size:	Size of the storage array * * Return: Number of trace entries stored. */unsigned int stack_trace_save_user(unsigned long *store, unsigned int size){	stack_trace_consume_fn consume_entry = stack_trace_consume_entry;	struct stacktrace_cookie c = {		.store	= store,		.size	= size,	};	mm_segment_t fs; 	/* Trace user stack if not a kernel thread */	if (current->flags & PF_KTHREAD)		return 0; 	fs = force_uaccess_begin();	arch_stack_walk_user(consume_entry, &c, task_pt_regs(current));	force_uaccess_end(fs); 	return c.len;}#endif #else /* CONFIG_ARCH_STACKWALK */ /* * Architectures that do not implement save_stack_trace_*() * get these weak aliases and once-per-bootup warnings * (whenever this facility is utilized - for example by procfs): */__weak voidsave_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace){	WARN_ONCE(1, KERN_INFO "save_stack_trace_tsk() not implemented yet.\n");} __weak voidsave_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace){	WARN_ONCE(1, KERN_INFO "save_stack_trace_regs() not implemented yet.\n");} /** * stack_trace_save - Save a stack trace into a storage array * @store:	Pointer to storage array * @size:	Size of the storage array * @skipnr:	Number of entries to skip at the start of the stack trace * * Return: Number of trace entries stored */unsigned int stack_trace_save(unsigned long *store, unsigned int size,			      unsigned int skipnr){	struct stack_trace trace = {		.entries	= store,		.max_entries	= size,		.skip		= skipnr + 1,	}; 	save_stack_trace(&trace);	return trace.nr_entries;}EXPORT_SYMBOL_GPL(stack_trace_save); /** * stack_trace_save_tsk - Save a task stack trace into a storage array * @task:	The task to examine * @store:	Pointer to storage array * @size:	Size of the storage array * @skipnr:	Number of entries to skip at the start of the stack trace * * Return: Number of trace entries stored */unsigned int stack_trace_save_tsk(struct task_struct *task,				  unsigned long *store, unsigned int size,				  unsigned int skipnr){	struct stack_trace trace = {		.entries	= store,		.max_entries	= size,		/* skip this function if they are tracing us */		.skip	= skipnr + (current == task),	}; 	save_stack_trace_tsk(task, &trace);	return trace.nr_entries;} /** * stack_trace_save_regs - Save a stack trace based on pt_regs into a storage array * @regs:	Pointer to pt_regs to examine * @store:	Pointer to storage array * @size:	Size of the storage array * @skipnr:	Number of entries to skip at the start of the stack trace * * Return: Number of trace entries stored */unsigned int stack_trace_save_regs(struct pt_regs *regs, unsigned long *store,				   unsigned int size, unsigned int skipnr){	struct stack_trace trace = {		.entries	= store,		.max_entries	= size,		.skip		= skipnr,	}; 	save_stack_trace_regs(regs, &trace);	return trace.nr_entries;} #ifdef CONFIG_HAVE_RELIABLE_STACKTRACE/** * stack_trace_save_tsk_reliable - Save task stack with verification * @tsk:	Pointer to the task to examine * @store:	Pointer to storage array * @size:	Size of the storage array * * Return:	An error if it detects any unreliable features of the *		stack. Otherwise it guarantees that the stack trace is *		reliable and returns the number of entries stored. * * If the task is not 'current', the caller *must* ensure the task is inactive. */int stack_trace_save_tsk_reliable(struct task_struct *tsk, unsigned long *store,				  unsigned int size){	struct stack_trace trace = {		.entries	= store,		.max_entries	= size,	};	int ret = save_stack_trace_tsk_reliable(tsk, &trace); 	return ret ? ret : trace.nr_entries;}#endif #ifdef CONFIG_USER_STACKTRACE_SUPPORT/** * stack_trace_save_user - Save a user space stack trace into a storage array * @store:	Pointer to storage array * @size:	Size of the storage array * * Return: Number of trace entries stored */unsigned int stack_trace_save_user(unsigned long *store, unsigned int size){	struct stack_trace trace = {		.entries	= store,		.max_entries	= size,	}; 	save_stack_trace_user(&trace);	return trace.nr_entries;}#endif /* CONFIG_USER_STACKTRACE_SUPPORT */ #endif /* !CONFIG_ARCH_STACKWALK */ static inline bool in_irqentry_text(unsigned long ptr){	return (ptr >= (unsigned long)&__irqentry_text_start &&		ptr < (unsigned long)&__irqentry_text_end) ||		(ptr >= (unsigned long)&__softirqentry_text_start &&		 ptr < (unsigned long)&__softirqentry_text_end);} /** * filter_irq_stacks - Find first IRQ stack entry in trace * @entries:	Pointer to stack trace array * @nr_entries:	Number of entries in the storage array * * Return: Number of trace entries until IRQ stack starts. */unsigned int filter_irq_stacks(unsigned long *entries, unsigned int nr_entries){	unsigned int i; 	for (i = 0; i < nr_entries; i++) {		if (in_irqentry_text(entries[i])) {			/* Include the irqentry function into the stack. */			return i + 1;		}	}	return nr_entries;}EXPORT_SYMBOL_GPL(filter_irq_stacks);