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/*
* kernel/stacktrace.c
*
* Stack trace management functions
*
* Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
*/
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/kallsyms.h>
#include <linux/stacktrace.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(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);
void print_stack_trace(struct stack_trace *trace, int spaces)
{
stack_trace_print(trace->entries, trace->nr_entries, spaces);
}
EXPORT_SYMBOL_GPL(print_stack_trace);
/**
* 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, 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);
int snprint_stack_trace(char *buf, size_t size,
struct stack_trace *trace, int spaces)
{
return stack_trace_snprint(buf, size, trace->entries,
trace->nr_entries, spaces);
}
EXPORT_SYMBOL_GPL(snprint_stack_trace);
/*
* 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 void
save_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 void
save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
{
WARN_ONCE(1, KERN_INFO "save_stack_trace_regs() not implemented yet.\n");
}
__weak int
save_stack_trace_tsk_reliable(struct task_struct *tsk,
struct stack_trace *trace)
{
WARN_ONCE(1, KERN_INFO "save_stack_tsk_reliable() not implemented yet.\n");
return -ENOSYS;
}
/**
* 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 = skipnr + 1,
};
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 */
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