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/*
* Stack trace management functions
*
* Copyright (C) 2006-2009 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
*/
#include <linux/sched.h>
#include <linux/stacktrace.h>
#include <linux/module.h>
#include <linux/uaccess.h>
#include <asm/stacktrace.h>
#include <linux/mm.h>
static int save_stack_stack(void *data, char *name)
{
return 0;
}
static void
__save_stack_address(void *data, unsigned long addr, bool reliable, bool nosched)
{
struct stack_trace *trace = data;
#ifdef CONFIG_FRAME_POINTER
if (!reliable)
return;
#endif
if (nosched && in_sched_functions(addr))
return;
if (trace->skip > 0) {
trace->skip--;
return;
}
if (trace->nr_entries < trace->max_entries)
trace->entries[trace->nr_entries++] = addr;
}
static void save_stack_address(void *data, unsigned long addr, int reliable)
{
return __save_stack_address(data, addr, reliable, false);
}
static void
save_stack_address_nosched(void *data, unsigned long addr, int reliable)
{
return __save_stack_address(data, addr, reliable, true);
}
static const struct stacktrace_ops save_stack_ops = {
.stack = save_stack_stack,
.address = save_stack_address,
.walk_stack = print_context_stack,
};
static const struct stacktrace_ops save_stack_ops_nosched = {
.stack = save_stack_stack,
.address = save_stack_address_nosched,
.walk_stack = print_context_stack,
};
/*
* Save stack-backtrace addresses into a stack_trace buffer.
*/
void save_stack_trace(struct stack_trace *trace)
{
dump_trace(current, NULL, NULL, 0, &save_stack_ops, trace);
if (trace->nr_entries < trace->max_entries)
trace->entries[trace->nr_entries++] = ULONG_MAX;
}
EXPORT_SYMBOL_GPL(save_stack_trace);
void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
{
dump_trace(current, regs, NULL, 0, &save_stack_ops, trace);
if (trace->nr_entries < trace->max_entries)
trace->entries[trace->nr_entries++] = ULONG_MAX;
}
void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
{
dump_trace(tsk, NULL, NULL, 0, &save_stack_ops_nosched, trace);
if (trace->nr_entries < trace->max_entries)
trace->entries[trace->nr_entries++] = ULONG_MAX;
}
EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
/* Userspace stacktrace - based on kernel/trace/trace_sysprof.c */
struct stack_frame_user {
const void __user *next_fp;
unsigned long ret_addr;
};
static int
__copy_stack_frame(const void __user *fp, void *frame, unsigned long framesize)
{
int ret;
if (!access_ok(VERIFY_READ, fp, framesize))
return 0;
ret = 1;
pagefault_disable();
if (__copy_from_user_inatomic(frame, fp, framesize))
ret = 0;
pagefault_enable();
return ret;
}
#ifdef CONFIG_COMPAT
#include <asm/compat.h>
struct compat_stack_frame_user {
compat_uptr_t next_fp;
compat_ulong_t ret_addr;
};
static inline int copy_stack_frame(const void __user *fp,
struct stack_frame_user *frame)
{
struct compat_stack_frame_user frame32 = { 0 };
if (!test_thread_flag(TIF_IA32))
return __copy_stack_frame(fp, frame, sizeof(*frame));
if (!__copy_stack_frame(fp, &frame32, sizeof(frame32)))
return 0;
frame->next_fp = compat_ptr(frame32.next_fp);
frame->ret_addr = (unsigned long)frame32.ret_addr;
return 1;
}
static inline int access_frame(struct task_struct *task, unsigned long addr,
struct stack_frame_user *frame)
{
struct compat_stack_frame_user frame32 = { 0 };
if (!test_tsk_thread_flag(task, TIF_IA32))
return access_process_vm(task, addr,
(void *)frame, sizeof(*frame), 0);
if (!access_process_vm(task, addr, (void *)&frame32,
sizeof(frame32), 0))
return 0;
frame->next_fp = compat_ptr(frame32.next_fp);
frame->ret_addr = (unsigned long)frame32.ret_addr;
return 1;
}
#else
static inline int copy_stack_frame(const void __user *fp,
struct stack_frame_user *frame)
{
return __copy_stack_frame(fp, frame, sizeof(*frame));
}
static inline int access_frame(struct task_struct *task, unsigned long addr,
struct stack_frame_user *frame)
{
return access_process_vm(task, addr, (void *)frame, sizeof(*frame), 0);
}
#endif
static inline void __save_stack_trace_user(struct stack_trace *trace)
{
const struct pt_regs *regs = task_pt_regs(current);
const void __user *fp = (const void __user *)regs->bp;
if (trace->nr_entries < trace->max_entries)
trace->entries[trace->nr_entries++] = regs->ip;
while (trace->nr_entries < trace->max_entries) {
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) {
trace->entries[trace->nr_entries++] =
frame.ret_addr;
}
if (fp == frame.next_fp)
break;
fp = frame.next_fp;
}
}
void save_stack_trace_user(struct stack_trace *trace)
{
/*
* Trace user stack if we are not a kernel thread
*/
if (current->mm) {
__save_stack_trace_user(trace);
}
if (trace->nr_entries < trace->max_entries)
trace->entries[trace->nr_entries++] = ULONG_MAX;
}
static inline void __save_stack_trace_user_task(struct task_struct *task,
struct stack_trace *trace)
{
const struct pt_regs *regs = task_pt_regs(task);
const void __user *fp;
unsigned long addr;
#ifdef CONFIG_SMP
if (task != current && task->state == TASK_RUNNING && task->on_cpu) {
/* To trap into kernel at least once */
smp_send_reschedule(task_cpu(task));
}
#endif
fp = (const void __user *)regs->bp;
if (trace->nr_entries < trace->max_entries)
trace->entries[trace->nr_entries++] = regs->ip;
while (trace->nr_entries < trace->max_entries) {
struct stack_frame_user frame;
frame.next_fp = NULL;
frame.ret_addr = 0;
addr = (unsigned long)fp;
if (!access_frame(task, addr, &frame))
break;
if ((unsigned long)fp < regs->sp)
break;
if (frame.ret_addr) {
trace->entries[trace->nr_entries++] =
frame.ret_addr;
}
if (fp == frame.next_fp)
break;
fp = frame.next_fp;
}
}
void save_stack_trace_user_task(struct task_struct *task,
struct stack_trace *trace)
{
if (task == current || !task) {
save_stack_trace_user(trace);
return;
}
if (task->mm)
__save_stack_trace_user_task(task, trace);
if (trace->nr_entries < trace->max_entries)
trace->entries[trace->nr_entries++] = ULONG_MAX;
}
EXPORT_SYMBOL_GPL(save_stack_trace_user_task);
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