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-rw-r--r--kernel/trace/ftrace.c38
1 files changed, 37 insertions, 1 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 2f32969..fdf913d 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -17,6 +17,7 @@
#include <linux/clocksource.h>
#include <linux/kallsyms.h>
#include <linux/seq_file.h>
+#include <linux/suspend.h>
#include <linux/debugfs.h>
#include <linux/hardirq.h>
#include <linux/kthread.h>
@@ -1736,9 +1737,12 @@ static void clear_ftrace_pid(struct pid *pid)
{
struct task_struct *p;
+ rcu_read_lock();
do_each_pid_task(pid, PIDTYPE_PID, p) {
clear_tsk_trace_trace(p);
} while_each_pid_task(pid, PIDTYPE_PID, p);
+ rcu_read_unlock();
+
put_pid(pid);
}
@@ -1746,9 +1750,11 @@ static void set_ftrace_pid(struct pid *pid)
{
struct task_struct *p;
+ rcu_read_lock();
do_each_pid_task(pid, PIDTYPE_PID, p) {
set_tsk_trace_trace(p);
} while_each_pid_task(pid, PIDTYPE_PID, p);
+ rcu_read_unlock();
}
static void clear_ftrace_pid_task(struct pid **pid)
@@ -1965,6 +1971,7 @@ ftrace_enable_sysctl(struct ctl_table *table, int write,
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
static atomic_t ftrace_graph_active;
+static struct notifier_block ftrace_suspend_notifier;
int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
{
@@ -2026,7 +2033,7 @@ free:
static int start_graph_tracing(void)
{
struct ftrace_ret_stack **ret_stack_list;
- int ret;
+ int ret, cpu;
ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
sizeof(struct ftrace_ret_stack *),
@@ -2035,6 +2042,10 @@ static int start_graph_tracing(void)
if (!ret_stack_list)
return -ENOMEM;
+ /* The cpu_boot init_task->ret_stack will never be freed */
+ for_each_online_cpu(cpu)
+ ftrace_graph_init_task(idle_task(cpu));
+
do {
ret = alloc_retstack_tasklist(ret_stack_list);
} while (ret == -EAGAIN);
@@ -2043,6 +2054,27 @@ static int start_graph_tracing(void)
return ret;
}
+/*
+ * Hibernation protection.
+ * The state of the current task is too much unstable during
+ * suspend/restore to disk. We want to protect against that.
+ */
+static int
+ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
+ void *unused)
+{
+ switch (state) {
+ case PM_HIBERNATION_PREPARE:
+ pause_graph_tracing();
+ break;
+
+ case PM_POST_HIBERNATION:
+ unpause_graph_tracing();
+ break;
+ }
+ return NOTIFY_DONE;
+}
+
int register_ftrace_graph(trace_func_graph_ret_t retfunc,
trace_func_graph_ent_t entryfunc)
{
@@ -2050,6 +2082,9 @@ int register_ftrace_graph(trace_func_graph_ret_t retfunc,
mutex_lock(&ftrace_sysctl_lock);
+ ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
+ register_pm_notifier(&ftrace_suspend_notifier);
+
atomic_inc(&ftrace_graph_active);
ret = start_graph_tracing();
if (ret) {
@@ -2075,6 +2110,7 @@ void unregister_ftrace_graph(void)
ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
ftrace_graph_entry = ftrace_graph_entry_stub;
ftrace_shutdown(FTRACE_STOP_FUNC_RET);
+ unregister_pm_notifier(&ftrace_suspend_notifier);
mutex_unlock(&ftrace_sysctl_lock);
}
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