[PATCH V2] tracing: Revert "tracing: Remove pid in task_rename tracing output"

[Xuewen Yan]

This reverts commit e3f6a42272e028c46695acc83fc7d7c42f2750ad.

The commit says that the tracepoint only deals with the current task,
however the following case is not current task:

comm_write() {
    p = get_proc_task(inode);
    if (!p)
        return -ESRCH;

    if (same_thread_group(current, p))
        set_task_comm(p, buffer);
}
where set_task_comm() calls __set_task_comm() which records
the update of p and not current.

So revert the patch to show pid.

Fixes: e3f6a42272e0 ("tracing: Remove pid in task_rename tracing output")
Reported-by: Guohua Yan <guohua....@unisoc.com>
Signed-off-by: Xuewen Yan <xuewen....@unisoc.com>
---
v2:
- update commit message (Steven)
---
 include/trace/events/task.h | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/include/trace/events/task.h b/include/trace/events/task.h
index 4f0759634306..b9a129eb54d9 100644
--- a/include/trace/events/task.h
+++ b/include/trace/events/task.h
@@ -38,19 +38,22 @@ TRACE_EVENT(task_rename,
        TP_ARGS(task, comm),
 
        TP_STRUCT__entry(
+               __field(        pid_t,  pid)
                __array(        char, oldcomm,  TASK_COMM_LEN)
                __array(        char, newcomm,  TASK_COMM_LEN)
                __field(        short,  oom_score_adj)
        ),
 
        TP_fast_assign(
+               __entry->pid = task->pid;
                memcpy(entry->oldcomm, task->comm, TASK_COMM_LEN);
                strscpy(entry->newcomm, comm, TASK_COMM_LEN);
                __entry->oom_score_adj = task->signal->oom_score_adj;
        ),
 
-       TP_printk("oldcomm=%s newcomm=%s oom_score_adj=%hd",
-                 __entry->oldcomm, __entry->newcomm, __entry->oom_score_adj)
+       TP_printk("pid=%d oldcomm=%s newcomm=%s oom_score_adj=%hd",
+               __entry->pid, __entry->oldcomm,
+               __entry->newcomm, __entry->oom_score_adj)
 );
 
 /**
-- 
2.25.1