This is a note to let you know that I've just added the patch titled
ntp: Read reference time only once
to the 6.12-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:
ntp-read-reference-time-only-once.patch
and it can be found in the queue-6.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 615a20c1b427738e2cd85b339363d4a9a164152f
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Date: Wed Sep 11 15:17:42 2024 +0200
ntp: Read reference time only once
[ Upstream commit 136bccbc2e78d3cd0bd8831e4c5a4509c0ddd945 ]
The reference time is required twice in ntp_update_offset(). It will not
change in the meantime as the calling code holds the timekeeper lock. Read
it only once and store it into a local variable.
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Anna-Maria Behnsen <anna-maria@xxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Acked-by: John Stultz <jstultz@xxxxxxxxxx>
Link: https://lore.kernel.org/all/20240911-devel-anna-maria-b4-timers-ptp-ntp-v1-6-2d52f4e13476@xxxxxxxxxxxxx
Stable-dep-of: f5807b0606da ("ntp: Remove invalid cast in time offset math")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index 905b0216b12dc..0bfd07de202a5 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -283,9 +283,8 @@ static inline s64 ntp_update_offset_fll(s64 offset64, long secs)
static void ntp_update_offset(long offset)
{
- s64 freq_adj;
- s64 offset64;
- long secs;
+ s64 freq_adj, offset64;
+ long secs, real_secs;
if (!(time_status & STA_PLL))
return;
@@ -303,11 +302,12 @@ static void ntp_update_offset(long offset)
* Select how the frequency is to be controlled
* and in which mode (PLL or FLL).
*/
- secs = (long)(__ktime_get_real_seconds() - time_reftime);
+ real_secs = __ktime_get_real_seconds();
+ secs = (long)(real_secs - time_reftime);
if (unlikely(time_status & STA_FREQHOLD))
secs = 0;
- time_reftime = __ktime_get_real_seconds();
+ time_reftime = real_secs;
offset64 = offset;
freq_adj = ntp_update_offset_fll(offset64, secs);
