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authorPavankumar Kondeti <pkondeti@codeaurora.org>2018-10-30 12:24:33 +0530
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2018-11-27 20:31:55 -0500
commit3054426dc68e5d63aa6a6e9b91ac4ec78e3f3805 (patch)
treef13ab8110247ddf2acfd5f68061825f35f877775 /include/trace
parentb1b35f2e218a5b57d03bbc3b0667d5064570dc60 (diff)
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sched, trace: Fix prev_state output in sched_switch tracepoint
commit 3f5fe9fef5b2 ("sched/debug: Fix task state recording/printout") tried to fix the problem introduced by a previous commit efb40f588b43 ("sched/tracing: Fix trace_sched_switch task-state printing"). However the prev_state output in sched_switch is still broken. task_state_index() uses fls() which considers the LSB as 1. Left shifting 1 by this value gives an incorrect mapping to the task state. Fix this by decrementing the value returned by __get_task_state() before shifting. Link: http://lkml.kernel.org/r/1540882473-1103-1-git-send-email-pkondeti@codeaurora.org Cc: stable@vger.kernel.org Fixes: 3f5fe9fef5b2 ("sched/debug: Fix task state recording/printout") Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'include/trace')
-rw-r--r--include/trace/events/sched.h12
1 files changed, 11 insertions, 1 deletions
diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index f07b270d4fc4..9a4bdfadab07 100644
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h
@@ -107,6 +107,8 @@ DEFINE_EVENT(sched_wakeup_template, sched_wakeup_new,
#ifdef CREATE_TRACE_POINTS
static inline long __trace_sched_switch_state(bool preempt, struct task_struct *p)
{
+ unsigned int state;
+
#ifdef CONFIG_SCHED_DEBUG
BUG_ON(p != current);
#endif /* CONFIG_SCHED_DEBUG */
@@ -118,7 +120,15 @@ static inline long __trace_sched_switch_state(bool preempt, struct task_struct *
if (preempt)
return TASK_REPORT_MAX;
- return 1 << task_state_index(p);
+ /*
+ * task_state_index() uses fls() and returns a value from 0-8 range.
+ * Decrement it by 1 (except TASK_RUNNING state i.e 0) before using
+ * it for left shift operation to get the correct task->state
+ * mapping.
+ */
+ state = task_state_index(p);
+
+ return state ? (1 << (state - 1)) : state;
}
#endif /* CREATE_TRACE_POINTS */