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Diffstat (limited to 'kernel/trace/trace_stack.c')
-rw-r--r--kernel/trace/trace_stack.c79
1 files changed, 34 insertions, 45 deletions
diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index 3f3449624..8abf1ba18 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -18,12 +18,6 @@
#define STACK_TRACE_ENTRIES 500
-#ifdef CC_USING_FENTRY
-# define fentry 1
-#else
-# define fentry 0
-#endif
-
static unsigned long stack_dump_trace[STACK_TRACE_ENTRIES+1] =
{ [0 ... (STACK_TRACE_ENTRIES)] = ULONG_MAX };
static unsigned stack_dump_index[STACK_TRACE_ENTRIES];
@@ -35,7 +29,7 @@ static unsigned stack_dump_index[STACK_TRACE_ENTRIES];
*/
static struct stack_trace max_stack_trace = {
.max_entries = STACK_TRACE_ENTRIES - 1,
- .entries = &stack_dump_trace[1],
+ .entries = &stack_dump_trace[0],
};
static unsigned long max_stack_size;
@@ -55,7 +49,7 @@ static inline void print_max_stack(void)
pr_emerg(" Depth Size Location (%d entries)\n"
" ----- ---- --------\n",
- max_stack_trace.nr_entries - 1);
+ max_stack_trace.nr_entries);
for (i = 0; i < max_stack_trace.nr_entries; i++) {
if (stack_dump_trace[i] == ULONG_MAX)
@@ -77,7 +71,7 @@ check_stack(unsigned long ip, unsigned long *stack)
unsigned long this_size, flags; unsigned long *p, *top, *start;
static int tracer_frame;
int frame_size = ACCESS_ONCE(tracer_frame);
- int i;
+ int i, x;
this_size = ((unsigned long)stack) & (THREAD_SIZE-1);
this_size = THREAD_SIZE - this_size;
@@ -91,9 +85,19 @@ check_stack(unsigned long ip, unsigned long *stack)
if (!object_is_on_stack(stack))
return;
+ /* Can't do this from NMI context (can cause deadlocks) */
+ if (in_nmi())
+ return;
+
local_irq_save(flags);
arch_spin_lock(&max_stack_lock);
+ /*
+ * RCU may not be watching, make it see us.
+ * The stack trace code uses rcu_sched.
+ */
+ rcu_irq_enter();
+
/* In case another CPU set the tracer_frame on us */
if (unlikely(!frame_size))
this_size -= tracer_frame;
@@ -105,26 +109,20 @@ check_stack(unsigned long ip, unsigned long *stack)
max_stack_size = this_size;
max_stack_trace.nr_entries = 0;
-
- if (using_ftrace_ops_list_func())
- max_stack_trace.skip = 4;
- else
- max_stack_trace.skip = 3;
+ max_stack_trace.skip = 3;
save_stack_trace(&max_stack_trace);
- /*
- * Add the passed in ip from the function tracer.
- * Searching for this on the stack will skip over
- * most of the overhead from the stack tracer itself.
- */
- stack_dump_trace[0] = ip;
- max_stack_trace.nr_entries++;
+ /* Skip over the overhead of the stack tracer itself */
+ for (i = 0; i < max_stack_trace.nr_entries; i++) {
+ if (stack_dump_trace[i] == ip)
+ break;
+ }
/*
* Now find where in the stack these are.
*/
- i = 0;
+ x = 0;
start = stack;
top = (unsigned long *)
(((unsigned long)start & ~(THREAD_SIZE-1)) + THREAD_SIZE);
@@ -139,12 +137,15 @@ check_stack(unsigned long ip, unsigned long *stack)
while (i < max_stack_trace.nr_entries) {
int found = 0;
- stack_dump_index[i] = this_size;
+ stack_dump_index[x] = this_size;
p = start;
for (; p < top && i < max_stack_trace.nr_entries; p++) {
+ if (stack_dump_trace[i] == ULONG_MAX)
+ break;
if (*p == stack_dump_trace[i]) {
- this_size = stack_dump_index[i++] =
+ stack_dump_trace[x] = stack_dump_trace[i++];
+ this_size = stack_dump_index[x++] =
(top - p) * sizeof(unsigned long);
found = 1;
/* Start the search from here */
@@ -156,7 +157,7 @@ check_stack(unsigned long ip, unsigned long *stack)
* out what that is, then figure it out
* now.
*/
- if (unlikely(!tracer_frame) && i == 1) {
+ if (unlikely(!tracer_frame)) {
tracer_frame = (p - stack) *
sizeof(unsigned long);
max_stack_size -= tracer_frame;
@@ -168,12 +169,17 @@ check_stack(unsigned long ip, unsigned long *stack)
i++;
}
+ max_stack_trace.nr_entries = x;
+ for (; x < i; x++)
+ stack_dump_trace[x] = ULONG_MAX;
+
if (task_stack_end_corrupted(current)) {
print_max_stack();
BUG();
}
out:
+ rcu_irq_exit();
arch_spin_unlock(&max_stack_lock);
local_irq_restore(flags);
}
@@ -192,24 +198,7 @@ stack_trace_call(unsigned long ip, unsigned long parent_ip,
if (per_cpu(trace_active, cpu)++ != 0)
goto out;
- /*
- * When fentry is used, the traced function does not get
- * its stack frame set up, and we lose the parent.
- * The ip is pretty useless because the function tracer
- * was called before that function set up its stack frame.
- * In this case, we use the parent ip.
- *
- * By adding the return address of either the parent ip
- * or the current ip we can disregard most of the stack usage
- * caused by the stack tracer itself.
- *
- * The function tracer always reports the address of where the
- * mcount call was, but the stack will hold the return address.
- */
- if (fentry)
- ip = parent_ip;
- else
- ip += MCOUNT_INSN_SIZE;
+ ip += MCOUNT_INSN_SIZE;
check_stack(ip, &stack);
@@ -284,7 +273,7 @@ __next(struct seq_file *m, loff_t *pos)
{
long n = *pos - 1;
- if (n >= max_stack_trace.nr_entries || stack_dump_trace[n] == ULONG_MAX)
+ if (n > max_stack_trace.nr_entries || stack_dump_trace[n] == ULONG_MAX)
return NULL;
m->private = (void *)n;
@@ -354,7 +343,7 @@ static int t_show(struct seq_file *m, void *v)
seq_printf(m, " Depth Size Location"
" (%d entries)\n"
" ----- ---- --------\n",
- max_stack_trace.nr_entries - 1);
+ max_stack_trace.nr_entries);
if (!stack_tracer_enabled && !max_stack_size)
print_disabled(m);