tracing: Support multiple pids in set_pid_ftrace file
Adding the possibility to set more than 1 pid in the set_pid_ftrace file, thus allowing to trace more than 1 independent processes. Usage: sh-4.0# echo 284 > ./set_ftrace_pid sh-4.0# cat ./set_ftrace_pid 284 sh-4.0# echo 1 >> ./set_ftrace_pid sh-4.0# echo 0 >> ./set_ftrace_pid sh-4.0# cat ./set_ftrace_pid swapper tasks 1 284 sh-4.0# echo 4 > ./set_ftrace_pid sh-4.0# cat ./set_ftrace_pid 4 sh-4.0# echo > ./set_ftrace_pid sh-4.0# cat ./set_ftrace_pid no pid sh-4.0# Signed-off-by: Jiri Olsa <jolsa@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <20091013203425.565454612@goodmis.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
jolsa@redhat.com
Ingo Molnar
parent
194ec34184
commit
756d17ee7e
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@ -60,6 +60,13 @@ static int last_ftrace_enabled;
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/* Quick disabling of function tracer. */
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int function_trace_stop;
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/* List for set_ftrace_pid's pids. */
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LIST_HEAD(ftrace_pids);
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struct ftrace_pid {
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struct list_head list;
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struct pid *pid;
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};
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/*
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* ftrace_disabled is set when an anomaly is discovered.
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* ftrace_disabled is much stronger than ftrace_enabled.
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@ -159,7 +166,7 @@ static int __register_ftrace_function(struct ftrace_ops *ops)
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else
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func = ftrace_list_func;
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if (ftrace_pid_trace) {
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if (!list_empty(&ftrace_pids)) {
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set_ftrace_pid_function(func);
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func = ftrace_pid_func;
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}
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@ -207,7 +214,7 @@ static int __unregister_ftrace_function(struct ftrace_ops *ops)
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if (ftrace_list->next == &ftrace_list_end) {
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ftrace_func_t func = ftrace_list->func;
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if (ftrace_pid_trace) {
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if (!list_empty(&ftrace_pids)) {
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set_ftrace_pid_function(func);
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func = ftrace_pid_func;
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}
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@ -235,7 +242,7 @@ static void ftrace_update_pid_func(void)
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func = __ftrace_trace_function;
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#endif
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if (ftrace_pid_trace) {
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if (!list_empty(&ftrace_pids)) {
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set_ftrace_pid_function(func);
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func = ftrace_pid_func;
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} else {
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@ -825,8 +832,6 @@ static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
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}
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#endif /* CONFIG_FUNCTION_PROFILER */
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/* set when tracing only a pid */
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struct pid *ftrace_pid_trace;
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static struct pid * const ftrace_swapper_pid = &init_struct_pid;
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#ifdef CONFIG_DYNAMIC_FTRACE
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@ -2758,23 +2763,6 @@ static inline void ftrace_startup_enable(int command) { }
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# define ftrace_shutdown_sysctl() do { } while (0)
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#endif /* CONFIG_DYNAMIC_FTRACE */
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static ssize_t
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ftrace_pid_read(struct file *file, char __user *ubuf,
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size_t cnt, loff_t *ppos)
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{
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char buf[64];
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int r;
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if (ftrace_pid_trace == ftrace_swapper_pid)
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r = sprintf(buf, "swapper tasks\n");
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else if (ftrace_pid_trace)
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r = sprintf(buf, "%u\n", pid_vnr(ftrace_pid_trace));
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else
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r = sprintf(buf, "no pid\n");
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return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
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}
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static void clear_ftrace_swapper(void)
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{
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struct task_struct *p;
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@ -2825,14 +2813,12 @@ static void set_ftrace_pid(struct pid *pid)
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rcu_read_unlock();
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}
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static void clear_ftrace_pid_task(struct pid **pid)
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static void clear_ftrace_pid_task(struct pid *pid)
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{
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if (*pid == ftrace_swapper_pid)
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if (pid == ftrace_swapper_pid)
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clear_ftrace_swapper();
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else
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clear_ftrace_pid(*pid);
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*pid = NULL;
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clear_ftrace_pid(pid);
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}
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static void set_ftrace_pid_task(struct pid *pid)
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@ -2843,11 +2829,140 @@ static void set_ftrace_pid_task(struct pid *pid)
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set_ftrace_pid(pid);
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}
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static int ftrace_pid_add(int p)
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{
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struct pid *pid;
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struct ftrace_pid *fpid;
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int ret = -EINVAL;
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mutex_lock(&ftrace_lock);
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if (!p)
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pid = ftrace_swapper_pid;
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else
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pid = find_get_pid(p);
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if (!pid)
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goto out;
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ret = 0;
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list_for_each_entry(fpid, &ftrace_pids, list)
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if (fpid->pid == pid)
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goto out_put;
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ret = -ENOMEM;
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fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
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if (!fpid)
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goto out_put;
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list_add(&fpid->list, &ftrace_pids);
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fpid->pid = pid;
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set_ftrace_pid_task(pid);
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ftrace_update_pid_func();
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ftrace_startup_enable(0);
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mutex_unlock(&ftrace_lock);
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return 0;
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out_put:
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if (pid != ftrace_swapper_pid)
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put_pid(pid);
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out:
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mutex_unlock(&ftrace_lock);
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return ret;
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}
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static void ftrace_pid_reset(void)
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{
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struct ftrace_pid *fpid, *safe;
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mutex_lock(&ftrace_lock);
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list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
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struct pid *pid = fpid->pid;
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clear_ftrace_pid_task(pid);
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list_del(&fpid->list);
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kfree(fpid);
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}
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ftrace_update_pid_func();
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ftrace_startup_enable(0);
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mutex_unlock(&ftrace_lock);
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}
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static void *fpid_start(struct seq_file *m, loff_t *pos)
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{
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mutex_lock(&ftrace_lock);
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if (list_empty(&ftrace_pids) && (!*pos))
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return (void *) 1;
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return seq_list_start(&ftrace_pids, *pos);
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}
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static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
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{
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if (v == (void *)1)
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return NULL;
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return seq_list_next(v, &ftrace_pids, pos);
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}
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static void fpid_stop(struct seq_file *m, void *p)
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{
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mutex_unlock(&ftrace_lock);
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}
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static int fpid_show(struct seq_file *m, void *v)
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{
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const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
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if (v == (void *)1) {
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seq_printf(m, "no pid\n");
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return 0;
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}
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if (fpid->pid == ftrace_swapper_pid)
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seq_printf(m, "swapper tasks\n");
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else
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seq_printf(m, "%u\n", pid_vnr(fpid->pid));
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return 0;
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}
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static const struct seq_operations ftrace_pid_sops = {
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.start = fpid_start,
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.next = fpid_next,
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.stop = fpid_stop,
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.show = fpid_show,
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};
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static int
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ftrace_pid_open(struct inode *inode, struct file *file)
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{
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int ret = 0;
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if ((file->f_mode & FMODE_WRITE) &&
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(file->f_flags & O_TRUNC))
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ftrace_pid_reset();
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if (file->f_mode & FMODE_READ)
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ret = seq_open(file, &ftrace_pid_sops);
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return ret;
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}
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static ssize_t
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ftrace_pid_write(struct file *filp, const char __user *ubuf,
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size_t cnt, loff_t *ppos)
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{
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struct pid *pid;
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char buf[64];
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long val;
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int ret;
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@ -2860,57 +2975,38 @@ ftrace_pid_write(struct file *filp, const char __user *ubuf,
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buf[cnt] = 0;
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/*
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* Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
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* to clean the filter quietly.
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*/
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strstrip(buf);
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if (strlen(buf) == 0)
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return 1;
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ret = strict_strtol(buf, 10, &val);
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if (ret < 0)
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return ret;
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mutex_lock(&ftrace_lock);
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if (val < 0) {
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/* disable pid tracing */
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if (!ftrace_pid_trace)
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goto out;
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ret = ftrace_pid_add(val);
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clear_ftrace_pid_task(&ftrace_pid_trace);
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return ret ? ret : cnt;
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}
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} else {
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/* swapper task is special */
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if (!val) {
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pid = ftrace_swapper_pid;
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if (pid == ftrace_pid_trace)
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goto out;
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} else {
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pid = find_get_pid(val);
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static int
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ftrace_pid_release(struct inode *inode, struct file *file)
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{
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if (file->f_mode & FMODE_READ)
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seq_release(inode, file);
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if (pid == ftrace_pid_trace) {
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put_pid(pid);
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goto out;
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}
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}
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if (ftrace_pid_trace)
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clear_ftrace_pid_task(&ftrace_pid_trace);
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if (!pid)
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goto out;
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ftrace_pid_trace = pid;
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set_ftrace_pid_task(ftrace_pid_trace);
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}
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/* update the function call */
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ftrace_update_pid_func();
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ftrace_startup_enable(0);
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out:
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mutex_unlock(&ftrace_lock);
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return cnt;
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return 0;
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}
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static const struct file_operations ftrace_pid_fops = {
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.read = ftrace_pid_read,
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.write = ftrace_pid_write,
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.open = ftrace_pid_open,
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.write = ftrace_pid_write,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = ftrace_pid_release,
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};
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static __init int ftrace_init_debugfs(void)
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@ -496,12 +496,12 @@ print_graph_function(struct trace_iterator *iter)
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}
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#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
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extern struct pid *ftrace_pid_trace;
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extern struct list_head ftrace_pids;
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#ifdef CONFIG_FUNCTION_TRACER
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static inline int ftrace_trace_task(struct task_struct *task)
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{
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if (!ftrace_pid_trace)
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if (list_empty(&ftrace_pids))
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return 1;
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return test_tsk_trace_trace(task);
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