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ftrace: use struct pid 

Impact: clean up, extend PID filtering to PID namespaces

Eric Biederman suggested using the struct pid for filtering on
pids in the kernel. This patch is based off of a demonstration
of an implementation that Eric sent me in an email.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Steven Rostedt 2008-12-04 00:26:40 -05:00 committed by Ingo Molnar
parent 5ef6476190
commit 978f3a45d9
2 changed files with 46 additions and 34 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

76
kernel/trace/ftrace.c
View File

@ -48,7 +48,7 @@ int ftrace_enabled __read_mostly;
static int last_ftrace_enabled;
/* set when tracing only a pid */
int ftrace_pid_trace = -1;
struct pid *ftrace_pid_trace;
/* Quick disabling of function tracer. */
int function_trace_stop;
@ -153,7 +153,7 @@ static int __register_ftrace_function(struct ftrace_ops *ops)
else
func = ftrace_list_func;
if (ftrace_pid_trace >= 0) {
if (ftrace_pid_trace) {
set_ftrace_pid_function(func);
func = ftrace_pid_func;
}
@ -209,7 +209,7 @@ static int __unregister_ftrace_function(struct ftrace_ops *ops)
if (ftrace_list->next == &ftrace_list_end) {
ftrace_func_t func = ftrace_list->func;
if (ftrace_pid_trace >= 0) {
if (ftrace_pid_trace) {
set_ftrace_pid_function(func);
func = ftrace_pid_func;
}
@ -239,7 +239,7 @@ static void ftrace_update_pid_func(void)
func = ftrace_trace_function;
if (ftrace_pid_trace >= 0) {
if (ftrace_pid_trace) {
set_ftrace_pid_function(func);
func = ftrace_pid_func;
} else {
@ -1678,18 +1678,40 @@ ftrace_pid_read(struct file *file, char __user *ubuf,
char buf[64];
int r;
if (ftrace_pid_trace >= 0)
r = sprintf(buf, "%u\n", ftrace_pid_trace);
if (ftrace_pid_trace)
r = sprintf(buf, "%u\n", pid_nr(ftrace_pid_trace));
else
r = sprintf(buf, "no pid\n");
return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
}
static void clear_ftrace_pid_task(struct pid **pid)
{
struct task_struct *p;
do_each_pid_task(*pid, PIDTYPE_PID, p) {
clear_tsk_trace_trace(p);
} while_each_pid_task(*pid, PIDTYPE_PID, p);
put_pid(*pid);
*pid = NULL;
}
static void set_ftrace_pid_task(struct pid *pid)
{
struct task_struct *p;
do_each_pid_task(pid, PIDTYPE_PID, p) {
set_tsk_trace_trace(p);
} while_each_pid_task(pid, PIDTYPE_PID, p);
}
static ssize_t
ftrace_pid_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
struct pid *pid;
char buf[64];
long val;
int ret;
@ -1707,40 +1729,30 @@ ftrace_pid_write(struct file *filp, const char __user *ubuf,
return ret;
mutex_lock(&ftrace_start_lock);
if (ret < 0) {
if (val < 0) {
/* disable pid tracing */
if (ftrace_pid_trace < 0)
if (!ftrace_pid_trace)
goto out;
ftrace_pid_trace = -1;
clear_ftrace_pid_task(&ftrace_pid_trace);
} else {
struct task_struct *p;
int found = 0;
pid = find_get_pid(val);
if (ftrace_pid_trace == val)
if (pid == ftrace_pid_trace) {
put_pid(pid);
goto out;
}
if (ftrace_pid_trace)
clear_ftrace_pid_task(&ftrace_pid_trace);
if (!pid)
goto out;
/*
* Find the task that matches this pid.
* TODO: use pid namespaces instead.
*/
rcu_read_lock();
for_each_process(p) {
if (p->pid == val) {
found = 1;
set_tsk_trace_trace(p);
} else if (test_tsk_trace_trace(p))
clear_tsk_trace_trace(p);
}
rcu_read_unlock();
ftrace_pid_trace = pid;
if (found)
ftrace_pid_trace = val;
else {
if (ftrace_pid_trace < 0)
goto out;
ftrace_pid_trace = -1;
}
set_ftrace_pid_task(ftrace_pid_trace);
}
/* update the function call */

4
kernel/trace/trace.h
View File

@ -541,11 +541,11 @@ print_graph_function(struct trace_iterator *iter)
}
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
extern int ftrace_pid_trace;
extern struct pid *ftrace_pid_trace;
static inline int ftrace_trace_task(struct task_struct *task)
{
if (ftrace_pid_trace < 0)
if (ftrace_pid_trace)
return 1;
return test_tsk_trace_trace(task);