ftrace: show virtual PID
Impact: fix PID output under namespaces
When current namespace is not the global namespace,
pid read from set_ftrace_pid is no correct.
# ~/newpid_namespace_run bash
# echo $$
1
# echo 1 > set_ftrace_pid
# cat set_ftrace_pid
3756
Since we write virtual PID to set_ftrace_pid, we need get
virtual PID when we read it.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <49C84D65.9050606@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 02d2de9..bb37711 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2264,7 +2264,7 @@
if (ftrace_pid_trace == ftrace_swapper_pid)
r = sprintf(buf, "swapper tasks\n");
else if (ftrace_pid_trace)
- r = sprintf(buf, "%u\n", pid_nr(ftrace_pid_trace));
+ r = sprintf(buf, "%u\n", pid_vnr(ftrace_pid_trace));
else
r = sprintf(buf, "no pid\n");