[PATCH RT 1/2] Fix latency histogram after "hrtimer: Set expiry time before switch_hrtimer_base()"

From: Steven Rostedt
Date: Wed Jul 02 2014 - 23:01:04 EST


3.2.60-rt88-rc1 stable review patch.
If anyone has any objections, please let me know.

------------------

From: Ben Hutchings <ben@xxxxxxxxxxxxxxx>

In an rt-kernel with CONFIG_MISSED_TIMER_OFFSETS_HIST enabled,
__hrtimer_start_range_ns() now crashes, as new_base is not assigned
before it is used.

Tested-by: Carsten Emde <C.Emde@xxxxxxxxx>
Cc: stable-rt@xxxxxxxxxxxxxxx
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
kernel/hrtimer.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index f54379023e16..2bd88f06a6d0 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -1033,6 +1033,11 @@ int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
#endif
}

+ hrtimer_set_expires_range_ns(timer, tim, delta_ns);
+
+ /* Switch the timer base, if necessary: */
+ new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);
+
#ifdef CONFIG_MISSED_TIMER_OFFSETS_HIST
{
ktime_t now = new_base->get_time();
@@ -1044,11 +1049,6 @@ int __hrtimer_start_range_ns(struct hrtimer *timer, ktime_t tim,
}
#endif

- hrtimer_set_expires_range_ns(timer, tim, delta_ns);
-
- /* Switch the timer base, if necessary: */
- new_base = switch_hrtimer_base(timer, base, mode & HRTIMER_MODE_PINNED);
-
timer_stats_hrtimer_set_start_info(timer);

leftmost = enqueue_hrtimer(timer, new_base);
--
2.0.0


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