Patch "timerfd: Handle relative timers with CONFIG_TIME_LOW_RES proper" has been added to the 4.4-stable tree

Patch "timerfd: Handle relative timers with CONFIG_TIME_LOW_RES proper" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    timerfd: Handle relative timers with CONFIG_TIME_LOW_RES proper

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     timerfd-handle-relative-timers-with-config_time_low_res-proper.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From b62526ed11a1fe3861ab98d40b7fdab8981d788a Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Thu, 14 Jan 2016 16:54:46 +0000
Subject: timerfd: Handle relative timers with CONFIG_TIME_LOW_RES proper

From: Thomas Gleixner <tglx@linutronix.de>

commit b62526ed11a1fe3861ab98d40b7fdab8981d788a upstream.

Helge reported that a relative timer can return a remaining time larger than
the programmed relative time on parisc and other architectures which have
CONFIG_TIME_LOW_RES set. This happens because we add a jiffie to the resulting
expiry time to prevent short timeouts.

Use the new function hrtimer_expires_remaining_adjusted() to calculate the
remaining time. It takes that extra added time into account for relative
timers.

Reported-and-tested-by: Helge Deller <deller@gmx.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: linux-m68k@lists.linux-m68k.org
Cc: dhowells@redhat.com
Link: http://lkml.kernel.org/r/20160114164159.354500742@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/timerfd.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/timerfd.c
+++ b/fs/timerfd.c
@@ -153,7 +153,7 @@ static ktime_t timerfd_get_remaining(str
 	if (isalarm(ctx))
 		remaining = alarm_expires_remaining(&ctx->t.alarm);
 	else
-		remaining = hrtimer_expires_remaining(&ctx->t.tmr);
+		remaining = hrtimer_expires_remaining_adjusted(&ctx->t.tmr);
 
 	return remaining.tv64 < 0 ? ktime_set(0, 0): remaining;
 }


Patches currently in stable-queue which might be from tglx@linutronix.de are

queue-4.4/itimers-handle-relative-timers-with-config_time_low_res-proper.patch
queue-4.4/futex-drop-refcount-if-requeue_pi-acquired-the-rtmutex.patch
queue-4.4/x86-mm-pat-avoid-truncation-when-converting-cpa-numpages-to-address.patch
queue-4.4/x86-uaccess-64-handle-the-caching-of-4-byte-nocache-copies-properly-in-__copy_user_nocache.patch
queue-4.4/timerfd-handle-relative-timers-with-config_time_low_res-proper.patch
queue-4.4/posix-timers-handle-relative-timers-with-config_time_low_res-proper.patch
queue-4.4/x86-mm-fix-vmalloc_fault-to-handle-large-pages-properly.patch
queue-4.4/x86-mm-fix-types-used-in-pgprot-cacheability-flags-translations.patch
queue-4.4/x86-uaccess-64-make-the-__copy_user_nocache-assembly-code-more-readable.patch