2006-07-03 15:24:40 +08:00
|
|
|
/*
|
|
|
|
* Stack trace management functions
|
|
|
|
*
|
2009-01-31 09:03:42 +08:00
|
|
|
* Copyright (C) 2006-2009 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
|
2006-07-03 15:24:40 +08:00
|
|
|
*/
|
|
|
|
#include <linux/sched.h>
|
2017-02-09 01:51:35 +08:00
|
|
|
#include <linux/sched/debug.h>
|
2017-02-09 01:51:37 +08:00
|
|
|
#include <linux/sched/task_stack.h>
|
2006-07-03 15:24:40 +08:00
|
|
|
#include <linux/stacktrace.h>
|
2016-07-14 08:18:56 +08:00
|
|
|
#include <linux/export.h>
|
2008-11-22 19:28:47 +08:00
|
|
|
#include <linux/uaccess.h>
|
2006-09-26 16:52:34 +08:00
|
|
|
#include <asm/stacktrace.h>
|
2016-09-17 03:18:14 +08:00
|
|
|
#include <asm/unwind.h>
|
2006-07-03 15:24:40 +08:00
|
|
|
|
2016-09-17 03:18:14 +08:00
|
|
|
static int save_stack_address(struct stack_trace *trace, unsigned long addr,
|
|
|
|
bool nosched)
|
2006-07-03 15:24:40 +08:00
|
|
|
{
|
2010-06-04 03:32:43 +08:00
|
|
|
if (nosched && in_sched_functions(addr))
|
2016-02-18 11:58:57 +08:00
|
|
|
return 0;
|
2016-09-17 03:18:14 +08:00
|
|
|
|
2006-09-26 16:52:34 +08:00
|
|
|
if (trace->skip > 0) {
|
|
|
|
trace->skip--;
|
2016-02-18 11:58:57 +08:00
|
|
|
return 0;
|
2006-07-03 15:24:40 +08:00
|
|
|
}
|
|
|
|
|
2016-09-17 03:18:14 +08:00
|
|
|
if (trace->nr_entries >= trace->max_entries)
|
|
|
|
return -1;
|
|
|
|
|
|
|
|
trace->entries[trace->nr_entries++] = addr;
|
|
|
|
return 0;
|
2010-06-04 03:32:43 +08:00
|
|
|
}
|
|
|
|
|
2017-09-29 17:23:35 +08:00
|
|
|
static void noinline __save_stack_trace(struct stack_trace *trace,
|
2016-09-17 03:18:14 +08:00
|
|
|
struct task_struct *task, struct pt_regs *regs,
|
|
|
|
bool nosched)
|
2008-01-26 04:08:34 +08:00
|
|
|
{
|
2016-09-17 03:18:14 +08:00
|
|
|
struct unwind_state state;
|
|
|
|
unsigned long addr;
|
2008-01-26 04:08:34 +08:00
|
|
|
|
2016-09-17 03:18:14 +08:00
|
|
|
if (regs)
|
|
|
|
save_stack_address(trace, regs->ip, nosched);
|
2006-07-03 15:24:40 +08:00
|
|
|
|
2016-09-17 03:18:14 +08:00
|
|
|
for (unwind_start(&state, task, regs, NULL); !unwind_done(&state);
|
|
|
|
unwind_next_frame(&state)) {
|
|
|
|
addr = unwind_get_return_address(&state);
|
|
|
|
if (!addr || save_stack_address(trace, addr, nosched))
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (trace->nr_entries < trace->max_entries)
|
|
|
|
trace->entries[trace->nr_entries++] = ULONG_MAX;
|
|
|
|
}
|
2008-01-26 04:08:34 +08:00
|
|
|
|
2006-07-03 15:24:40 +08:00
|
|
|
/*
|
|
|
|
* Save stack-backtrace addresses into a stack_trace buffer.
|
|
|
|
*/
|
2007-05-08 15:23:29 +08:00
|
|
|
void save_stack_trace(struct stack_trace *trace)
|
2006-07-03 15:24:40 +08:00
|
|
|
{
|
2017-09-29 17:23:35 +08:00
|
|
|
trace->skip++;
|
2016-09-17 03:18:14 +08:00
|
|
|
__save_stack_trace(trace, current, NULL, false);
|
2006-07-03 15:24:40 +08:00
|
|
|
}
|
2008-06-28 03:20:17 +08:00
|
|
|
EXPORT_SYMBOL_GPL(save_stack_trace);
|
2008-01-26 04:08:34 +08:00
|
|
|
|
2011-06-08 15:09:21 +08:00
|
|
|
void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
|
2008-05-20 17:15:43 +08:00
|
|
|
{
|
2016-09-17 03:18:14 +08:00
|
|
|
__save_stack_trace(trace, current, regs, false);
|
2008-05-20 17:15:43 +08:00
|
|
|
}
|
|
|
|
|
2008-01-26 04:08:34 +08:00
|
|
|
void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
|
|
|
|
{
|
2016-09-16 13:45:45 +08:00
|
|
|
if (!try_get_task_stack(tsk))
|
|
|
|
return;
|
|
|
|
|
2017-09-29 17:23:35 +08:00
|
|
|
if (tsk == current)
|
|
|
|
trace->skip++;
|
2016-09-17 03:18:14 +08:00
|
|
|
__save_stack_trace(trace, tsk, NULL, true);
|
2016-09-16 13:45:45 +08:00
|
|
|
|
|
|
|
put_task_stack(tsk);
|
2008-01-26 04:08:34 +08:00
|
|
|
}
|
2008-06-28 03:20:17 +08:00
|
|
|
EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
|
2008-11-22 19:28:47 +08:00
|
|
|
|
2017-02-14 09:42:28 +08:00
|
|
|
#ifdef CONFIG_HAVE_RELIABLE_STACKTRACE
|
|
|
|
|
2017-09-29 17:23:35 +08:00
|
|
|
static int __always_inline
|
|
|
|
__save_stack_trace_reliable(struct stack_trace *trace,
|
|
|
|
struct task_struct *task)
|
2017-02-14 09:42:28 +08:00
|
|
|
{
|
|
|
|
struct unwind_state state;
|
|
|
|
struct pt_regs *regs;
|
|
|
|
unsigned long addr;
|
|
|
|
|
2018-05-18 14:47:10 +08:00
|
|
|
for (unwind_start(&state, task, NULL, NULL);
|
|
|
|
!unwind_done(&state) && !unwind_error(&state);
|
2017-02-14 09:42:28 +08:00
|
|
|
unwind_next_frame(&state)) {
|
|
|
|
|
2018-01-01 00:18:06 +08:00
|
|
|
regs = unwind_get_entry_regs(&state, NULL);
|
2017-02-14 09:42:28 +08:00
|
|
|
if (regs) {
|
2018-05-18 14:47:10 +08:00
|
|
|
/* Success path for user tasks */
|
|
|
|
if (user_mode(regs))
|
|
|
|
goto success;
|
|
|
|
|
2017-02-14 09:42:28 +08:00
|
|
|
/*
|
|
|
|
* Kernel mode registers on the stack indicate an
|
|
|
|
* in-kernel interrupt or exception (e.g., preemption
|
|
|
|
* or a page fault), which can make frame pointers
|
|
|
|
* unreliable.
|
|
|
|
*/
|
|
|
|
|
2018-05-18 14:47:11 +08:00
|
|
|
if (IS_ENABLED(CONFIG_FRAME_POINTER))
|
|
|
|
return -EINVAL;
|
2017-02-14 09:42:28 +08:00
|
|
|
}
|
|
|
|
|
|
|
|
addr = unwind_get_return_address(&state);
|
|
|
|
|
|
|
|
/*
|
|
|
|
* A NULL or invalid return address probably means there's some
|
|
|
|
* generated code which __kernel_text_address() doesn't know
|
|
|
|
* about.
|
|
|
|
*/
|
2018-05-18 14:47:09 +08:00
|
|
|
if (!addr)
|
2017-02-14 09:42:28 +08:00
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
if (save_stack_address(trace, addr, false))
|
|
|
|
return -EINVAL;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Check for stack corruption */
|
2018-05-18 14:47:09 +08:00
|
|
|
if (unwind_error(&state))
|
2017-02-14 09:42:28 +08:00
|
|
|
return -EINVAL;
|
|
|
|
|
2018-05-18 14:47:10 +08:00
|
|
|
/* Success path for non-user tasks, i.e. kthreads and idle tasks */
|
|
|
|
if (!(task->flags & (PF_KTHREAD | PF_IDLE)))
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
success:
|
2017-02-14 09:42:28 +08:00
|
|
|
if (trace->nr_entries < trace->max_entries)
|
|
|
|
trace->entries[trace->nr_entries++] = ULONG_MAX;
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* This function returns an error if it detects any unreliable features of the
|
|
|
|
* stack. Otherwise it guarantees that the stack trace is reliable.
|
|
|
|
*
|
|
|
|
* If the task is not 'current', the caller *must* ensure the task is inactive.
|
|
|
|
*/
|
|
|
|
int save_stack_trace_tsk_reliable(struct task_struct *tsk,
|
|
|
|
struct stack_trace *trace)
|
|
|
|
{
|
|
|
|
int ret;
|
|
|
|
|
2017-12-19 05:13:44 +08:00
|
|
|
/*
|
|
|
|
* If the task doesn't have a stack (e.g., a zombie), the stack is
|
|
|
|
* "reliably" empty.
|
|
|
|
*/
|
2017-02-14 09:42:28 +08:00
|
|
|
if (!try_get_task_stack(tsk))
|
2017-12-19 05:13:44 +08:00
|
|
|
return 0;
|
2017-02-14 09:42:28 +08:00
|
|
|
|
|
|
|
ret = __save_stack_trace_reliable(trace, tsk);
|
|
|
|
|
|
|
|
put_task_stack(tsk);
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
#endif /* CONFIG_HAVE_RELIABLE_STACKTRACE */
|
|
|
|
|
2008-11-22 19:28:47 +08:00
|
|
|
/* Userspace stacktrace - based on kernel/trace/trace_sysprof.c */
|
|
|
|
|
2010-05-20 03:35:17 +08:00
|
|
|
struct stack_frame_user {
|
2008-11-22 19:28:47 +08:00
|
|
|
const void __user *next_fp;
|
2008-11-23 18:39:06 +08:00
|
|
|
unsigned long ret_addr;
|
2008-11-22 19:28:47 +08:00
|
|
|
};
|
|
|
|
|
2010-05-20 03:35:17 +08:00
|
|
|
static int
|
|
|
|
copy_stack_frame(const void __user *fp, struct stack_frame_user *frame)
|
2008-11-22 19:28:47 +08:00
|
|
|
{
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
if (!access_ok(VERIFY_READ, fp, sizeof(*frame)))
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
ret = 1;
|
|
|
|
pagefault_disable();
|
|
|
|
if (__copy_from_user_inatomic(frame, fp, sizeof(*frame)))
|
|
|
|
ret = 0;
|
|
|
|
pagefault_enable();
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
2008-11-23 18:39:06 +08:00
|
|
|
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) {
|
2010-05-20 03:35:17 +08:00
|
|
|
struct stack_frame_user frame;
|
2008-11-23 18:39:06 +08:00
|
|
|
|
|
|
|
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;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2008-11-22 19:28:47 +08:00
|
|
|
void save_stack_trace_user(struct stack_trace *trace)
|
|
|
|
{
|
|
|
|
/*
|
|
|
|
* Trace user stack if we are not a kernel thread
|
|
|
|
*/
|
|
|
|
if (current->mm) {
|
2008-11-23 18:39:06 +08:00
|
|
|
__save_stack_trace_user(trace);
|
2008-11-22 19:28:47 +08:00
|
|
|
}
|
|
|
|
if (trace->nr_entries < trace->max_entries)
|
|
|
|
trace->entries[trace->nr_entries++] = ULONG_MAX;
|
|
|
|
}
|