add ntp STA_INS_DEL fix

Herton notes:

 ------
  > commit 6b43ae8a619d17c4935c3320d2ef9e92bdeed05d upstream.
  >
  > This should have been backported when it was commited, but I
  > mistook the problem as requiring the ntp_lock changes
  > that landed in 3.4 in order for it to occur.
  >
  > Unfortunately the same issue can happen (with only one cpu)
  > as follows:
  > do_adjtimex()
  >  write_seqlock_irq(&xtime_lock);
  >   process_adjtimex_modes()
  >    process_adj_status()
  >     ntp_start_leap_timer()
  >      hrtimer_start()
  >       hrtimer_reprogram()
  >        tick_program_event()
  >         clockevents_program_event()
  >          ktime_get()
  >           seq = req_seqbegin(xtime_lock); [DEADLOCK]
  >
  > This deadlock will no always occur, as it requires the
  > leap_timer to force a hrtimer_reprogram which only happens
  > if its set and there's no sooner timer to expire.
  [...]

  I remember this came through the leapsecond deadlock & hrtimer/futex
  issue fixes. But I noted now commit 6b1859dba01c7d512b72d77e3fd7da8354235189
  ("ntp: Fix STA_INS/DEL clearing bug") was not included, and its changelog
  says it fixes a problem introduced with this. Wouldn't it be worth/right to
  also include it in 2.6.34? I didn't test etc., just detected through the
  changelog/description but would expect it would be affected too. I also
  noted it is missing from 3.2.y and 2.6.32.y stables, and perhaps should be
  scheduled for inclusion in their cases too.
 ------

JohnS also agreed this should be incorporated, and mentioned
a pending -tip commit should be considered once it is mainline.

Reported-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

2 files changed, 57 insertions, 0 deletions

diff --git a/queue/ntp-Fix-STA_INS-DEL-clearing-bug.patch b/queue/ntp-Fix-STA_INS-DEL-clearing-bug.patch
new file mode 100644
index 0000000..739215e
--- /dev/null
+++ b/queue/ntp-Fix-STA_INS-DEL-clearing-bug.patch
@@ -0,0 +1,56 @@
+From 6b1859dba01c7d512b72d77e3fd7da8354235189 Mon Sep 17 00:00:00 2001
+From: John Stultz <johnstul@us.ibm.com>
+Date: Fri, 13 Jul 2012 01:21:50 -0400
+Subject: [PATCH] ntp: Fix STA_INS/DEL clearing bug
+
+commit 6b1859dba01c7d512b72d77e3fd7da8354235189 upstream.
+
+In commit 6b43ae8a619d17c4935c3320d2ef9e92bdeed05d, I
+introduced a bug that kept the STA_INS or STA_DEL bit
+from being cleared from time_status via adjtimex()
+without forcing STA_PLL first.
+
+Usually once the STA_INS is set, it isn't cleared
+until the leap second is applied, so its unlikely this
+affected anyone. However during testing I noticed it
+took some effort to cancel a leap second once STA_INS
+was set.
+
+Signed-off-by: John Stultz <johnstul@us.ibm.com>
+Cc: Ingo Molnar <mingo@kernel.org>
+Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
+Cc: Richard Cochran <richardcochran@gmail.com>
+Cc: Prarit Bhargava <prarit@redhat.com>
+CC: stable@vger.kernel.org # 3.4
+Link: http://lkml.kernel.org/r/1342156917-25092-2-git-send-email-john.stultz@linaro.org
+Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
+
+diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
+index 70b33ab..b7fbadc 100644
+--- a/kernel/time/ntp.c
++++ b/kernel/time/ntp.c
+@@ -409,7 +409,9 @@ int second_overflow(unsigned long secs)
+ 			time_state = TIME_DEL;
+ 		break;
+ 	case TIME_INS:
+-		if (secs % 86400 == 0) {
++		if (!(time_status & STA_INS))
++			time_state = TIME_OK;
++		else if (secs % 86400 == 0) {
+ 			leap = -1;
+ 			time_state = TIME_OOP;
+ 			time_tai++;
+@@ -418,7 +420,9 @@ int second_overflow(unsigned long secs)
+ 		}
+ 		break;
+ 	case TIME_DEL:
+-		if ((secs + 1) % 86400 == 0) {
++		if (!(time_status & STA_DEL))
++			time_state = TIME_OK;
++		else if ((secs + 1) % 86400 == 0) {
+ 			leap = 1;
+ 			time_tai--;
+ 			time_state = TIME_WAIT;
+-- 
+1.7.12.rc2
+
diff --git a/queue/series b/queue/series
index 3eeab94..9b07bf1 100644
--- a/queue/series
+++ b/queue/series
@@ -113,6 +113,7 @@ ACPI-AC-prevent-OOPS-on-some-boxes-due-to-missing-ch.patch
 #leapsecond
 ntp-Fix-leap-second-hrtimer-livelock.patch
 ntp-Correct-TAI-offset-during-leap-second.patch
+ntp-Fix-STA_INS-DEL-clearing-bug.patch
 timekeeping-Fix-CLOCK_MONOTONIC-inconsistency-during.patch
 time-Move-common-updates-to-a-function.patch
 hrtimer-Provide-clock_was_set_delayed.patch