From fa3aa7a54fe6d3abf128f13cd4bbd40eaa48fed2 Mon Sep 17 00:00:00 2001
From: Frederic Weisbecker <fweisbec@gmail.com>
Date: Tue, 7 Mar 2017 10:55:34 +0100
Subject: [PATCH] jiffies: Revert bogus conversion of NSEC_PER_SEC to TICK_NSEC
commit 93825f2ec736 converted NSEC_PER_SEC to TICK_NSEC because the author
confused NSEC_PER_JIFFY with NSEC_PER_SEC.
As a result, the calculation of refined jiffies got broken, triggering
lockups.
Fixes: 93825f2ec736 ("jiffies: Reuse TICK_NSEC instead of NSEC_PER_JIFFY")
Reported-and-tested-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1488880534-3777-1-git-send-email-fweisbec@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
kernel/time/jiffies.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/time/jiffies.c b/kernel/time/jiffies.c
index 7906b3f0c41a1..497719127bf9f 100644
--- a/kernel/time/jiffies.c
+++ b/kernel/time/jiffies.c
@@ -125,7 +125,7 @@ int register_refined_jiffies(long cycles_per_second)
shift_hz += cycles_per_tick/2;
do_div(shift_hz, cycles_per_tick);
/* Calculate nsec_per_tick using shift_hz */
- nsec_per_tick = (u64)TICK_NSEC << 8;
+ nsec_per_tick = (u64)NSEC_PER_SEC << 8;
nsec_per_tick += (u32)shift_hz/2;
do_div(nsec_per_tick, (u32)shift_hz);
--
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