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-rw-r--r--kernel/trace/trace_stack.c70
1 files changed, 55 insertions, 15 deletions
diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index 3bdb44bde4b7..d0871bc0aca5 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -10,6 +10,7 @@
#include <linux/debugfs.h>
#include <linux/ftrace.h>
#include <linux/module.h>
+#include <linux/sysctl.h>
#include <linux/init.h>
#include <linux/fs.h>
#include "trace.h"
@@ -31,6 +32,10 @@ static raw_spinlock_t max_stack_lock =
static int stack_trace_disabled __read_mostly;
static DEFINE_PER_CPU(int, trace_active);
+static DEFINE_MUTEX(stack_sysctl_mutex);
+
+int stack_tracer_enabled;
+static int last_stack_tracer_enabled;
static inline void check_stack(void)
{
@@ -48,7 +53,7 @@ static inline void check_stack(void)
if (!object_is_on_stack(&this_size))
return;
- raw_local_irq_save(flags);
+ local_irq_save(flags);
__raw_spin_lock(&max_stack_lock);
/* a race could have already updated it */
@@ -78,6 +83,7 @@ static inline void check_stack(void)
* on a new max, so it is far from a fast path.
*/
while (i < max_stack_trace.nr_entries) {
+ int found = 0;
stack_dump_index[i] = this_size;
p = start;
@@ -86,17 +92,19 @@ static inline void check_stack(void)
if (*p == stack_dump_trace[i]) {
this_size = stack_dump_index[i++] =
(top - p) * sizeof(unsigned long);
+ found = 1;
/* Start the search from here */
start = p + 1;
}
}
- i++;
+ if (!found)
+ i++;
}
out:
__raw_spin_unlock(&max_stack_lock);
- raw_local_irq_restore(flags);
+ local_irq_restore(flags);
}
static void
@@ -107,8 +115,7 @@ stack_trace_call(unsigned long ip, unsigned long parent_ip)
if (unlikely(!ftrace_enabled || stack_trace_disabled))
return;
- resched = need_resched();
- preempt_disable_notrace();
+ resched = ftrace_preempt_disable();
cpu = raw_smp_processor_id();
/* no atomic needed, we only modify this variable by this cpu */
@@ -120,10 +127,7 @@ stack_trace_call(unsigned long ip, unsigned long parent_ip)
out:
per_cpu(trace_active, cpu)--;
/* prevent recursion in schedule */
- if (resched)
- preempt_enable_no_resched_notrace();
- else
- preempt_enable_notrace();
+ ftrace_preempt_enable(resched);
}
static struct ftrace_ops trace_ops __read_mostly =
@@ -166,16 +170,16 @@ stack_max_size_write(struct file *filp, const char __user *ubuf,
if (ret < 0)
return ret;
- raw_local_irq_save(flags);
+ local_irq_save(flags);
__raw_spin_lock(&max_stack_lock);
*ptr = val;
__raw_spin_unlock(&max_stack_lock);
- raw_local_irq_restore(flags);
+ local_irq_restore(flags);
return count;
}
-static struct file_operations stack_max_size_fops = {
+static const struct file_operations stack_max_size_fops = {
.open = tracing_open_generic,
.read = stack_max_size_read,
.write = stack_max_size_write,
@@ -273,7 +277,7 @@ static int t_show(struct seq_file *m, void *v)
return 0;
}
-static struct seq_operations stack_trace_seq_ops = {
+static const struct seq_operations stack_trace_seq_ops = {
.start = t_start,
.next = t_next,
.stop = t_stop,
@@ -289,12 +293,47 @@ static int stack_trace_open(struct inode *inode, struct file *file)
return ret;
}
-static struct file_operations stack_trace_fops = {
+static const struct file_operations stack_trace_fops = {
.open = stack_trace_open,
.read = seq_read,
.llseek = seq_lseek,
};
+int
+stack_trace_sysctl(struct ctl_table *table, int write,
+ struct file *file, void __user *buffer, size_t *lenp,
+ loff_t *ppos)
+{
+ int ret;
+
+ mutex_lock(&stack_sysctl_mutex);
+
+ ret = proc_dointvec(table, write, file, buffer, lenp, ppos);
+
+ if (ret || !write ||
+ (last_stack_tracer_enabled == stack_tracer_enabled))
+ goto out;
+
+ last_stack_tracer_enabled = stack_tracer_enabled;
+
+ if (stack_tracer_enabled)
+ register_ftrace_function(&trace_ops);
+ else
+ unregister_ftrace_function(&trace_ops);
+
+ out:
+ mutex_unlock(&stack_sysctl_mutex);
+ return ret;
+}
+
+static __init int enable_stacktrace(char *str)
+{
+ stack_tracer_enabled = 1;
+ last_stack_tracer_enabled = 1;
+ return 1;
+}
+__setup("stacktrace", enable_stacktrace);
+
static __init int stack_trace_init(void)
{
struct dentry *d_tracer;
@@ -312,7 +351,8 @@ static __init int stack_trace_init(void)
if (!entry)
pr_warning("Could not create debugfs 'stack_trace' entry\n");
- register_ftrace_function(&trace_ops);
+ if (stack_tracer_enabled)
+ register_ftrace_function(&trace_ops);
return 0;
}