4.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
commit 3f5fe9fef5b2da06b6319fab8123056da5217c3f upstream.
The recent conversion of the task state recording to use task_state_index()
broke the sched_switch tracepoint task state output.
task_state_index() returns surprisingly an index (0-7) which is then
printed with __print_flags() applying bitmasks. Not really working and
resulting in weird states like 'prev_state=t' instead of 'prev_state=I'.
Use TASK_REPORT_MAX instead of TASK_STATE_MAX to report preemption. Build a
bitmask from the return value of task_state_index() and store it in
entry->prev_state, which makes __print_flags() work as expected.
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Fixes: efb40f588b43 ("sched/tracing: Fix trace_sched_switch task-state printing")
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1711221304180.1751@nanos
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
include/trace/events/sched.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h
@@ -116,9 +116,9 @@ static inline long __trace_sched_switch_
* RUNNING (we will not have dequeued if state != RUNNING).
*/
if (preempt)
- return TASK_STATE_MAX;
+ return TASK_REPORT_MAX;
- return __get_task_state(p);
+ return 1 << __get_task_state(p);
}
#endif /* CREATE_TRACE_POINTS */
@@ -164,7 +164,7 @@ TRACE_EVENT(sched_switch,
{ 0x40, "P" }, { 0x80, "I" }) :
"R",
- __entry->prev_state & TASK_STATE_MAX ? "+" : "",
+ __entry->prev_state & TASK_REPORT_MAX ? "+" : "",
__entry->next_comm, __entry->next_pid, __entry->next_prio)
);
