[rt] Fix latency histogram after "hrtimer: Set expiry time before switch_hrtimer_base()" in 3.14.6

svn path=/dists/sid/linux/; revision=21478

debian/changelog

@@ -54,6 +54,8 @@ linux (3.14.9-1) UNRELEASED; urgency=medium
     - propagate aufs file references to new vmas created by remap_file_pages()
   * linux-image: Make initramfs support unconditional
   * [x86] x86_32, entry: Do syscall exit work on badsys (CVE-2014-4508)
+  * [rt] Fix latency histogram after "hrtimer: Set expiry time before
+    switch_hrtimer_base()" in 3.14.6
 
   [ Aurelien Jarno ]
   * [arm64] Enable COMPAT to support 32-bit binaries.

debian/config/featureset-rt/config

@@ -1,10 +1,7 @@
 # CONFIG_PREEMPT_VOLUNTARY is not set
 CONFIG_PREEMPT_RT_FULL=y
 CONFIG_SCHED_TRACER=y
-#. This option is broken after commit 84ea7fe37908
-#. ('hrtimer: Set expiry time before switch_hrtimer_base()') but should be
-#. enabled when this is resolved
-# CONFIG_MISSED_TIMER_OFFSETS_HIST is not set
+CONFIG_MISSED_TIMER_OFFSETS_HIST=y
 CONFIG_WAKEUP_LATENCY_HIST=y
 
 ## disable aufs as it's not needed on rt and conflicts with fs-dentry-use-seqlock.patch

debian/patches/features/all/rt/fix-latency-histogram-after-hrtimer-set-expiry-time-before-switch_hrtimer_base.patch

@@ -0,0 +1,39 @@
+From: Ben Hutchings <ben@decadent.org.uk>
+Date: Sat, 28 Jun 2014 23:34:48 +0100
+Subject: Fix latency histogram after "hrtimer: Set expiry time before switch_hrtimer_base()"
+Forwarded: http://mid.gmane.org/1403994888.23472.116.camel@deadeye.wl.decadent.org.uk
+
+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.
+
+Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
+Tested-by: Carsten Emde <C.Emde@osadl.org>
+Cc: stable-rt@vger.kernel.org
+---
+--- a/kernel/hrtimer.c
++++ b/kernel/hrtimer.c
+@@ -1106,6 +1106,11 @@ int __hrtimer_start_range_ns(struct hrti
+ #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();
+@@ -1117,11 +1122,6 @@ int __hrtimer_start_range_ns(struct hrti
+ 	}
+ #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);

debian/patches/series-rt

@@ -658,3 +658,4 @@ features/all/rt/disable-preempt-lazy-on-x86-64.patch
 
 # Add RT to version
 features/all/rt/localversion.patch
+features/all/rt/fix-latency-histogram-after-hrtimer-set-expiry-time-before-switch_hrtimer_base.patch