The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 3f5fe9fef5b2da06b6319fab8123056da5217c3f Mon Sep 17 00:00:00 2001
From: Thomas Gleixner tglx@linutronix.de Date: Wed, 22 Nov 2017 13:05:48 +0100 Subject: [PATCH] sched/debug: Fix task state recording/printout
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@linutronix.de Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Paul E. McKenney paulmck@linux.vnet.ibm.com Cc: Peter Zijlstra peterz@infradead.org Cc: Steven Rostedt rostedt@goodmis.org Cc: stable@vger.kernel.org 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@kernel.org
diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h index 306b31de5194..bc01e06bc716 100644 --- a/include/trace/events/sched.h +++ b/include/trace/events/sched.h @@ -116,9 +116,9 @@ static inline long __trace_sched_switch_state(bool preempt, struct task_struct * * RUNNING (we will not have dequeued if state != RUNNING). */ if (preempt) - return TASK_STATE_MAX; + return TASK_REPORT_MAX;
- return task_state_index(p); + return 1 << task_state_index(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) );