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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2016-11-16 16:36:26 +0100
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2016-11-17 06:56:38 +0100
commit191ce9d1fde84190f18cd3faf0ef8594f442b313 (patch)
tree50814453e4dc64c4ec68dde13b09c533d6b1bf9c /arch/s390/kernel/time.c
parent68962269a4afda51e2d4794e82b5e187d7710b39 (diff)
downloadlinux-191ce9d1fde84190f18cd3faf0ef8594f442b313.tar.bz2
s390/time: fix clocksource steering for negative clock offsets
The TOD clock offset injected by an STP sync check can be negative. If the resulting total tod_steering_delta gets negative the kernel will panic. Change the type of tod_steering_delta to a signed type. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Fixes: 75c7b6f3f6ba ("s390/time: steer clocksource on STP sync events") Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/kernel/time.c')
-rw-r--r--arch/s390/kernel/time.c7
1 files changed, 3 insertions, 4 deletions
diff --git a/arch/s390/kernel/time.c b/arch/s390/kernel/time.c
index 33082f6cbb5d..867d0a057046 100644
--- a/arch/s390/kernel/time.c
+++ b/arch/s390/kernel/time.c
@@ -63,7 +63,7 @@ unsigned char ptff_function_mask[16];
static unsigned long long lpar_offset;
static unsigned long long initial_leap_seconds;
static unsigned long long tod_steering_end;
-static unsigned long long tod_steering_delta;
+static long long tod_steering_delta;
/*
* Get time offsets with PTFF
@@ -223,8 +223,7 @@ static cycle_t read_tod_clock(struct clocksource *cs)
* therefore steered in ~9h. The adjust will decrease
* over time, until it finally reaches 0.
*/
- now += ((s64) tod_steering_delta < 0) ?
- (adj >> 15) : -(adj >> 15);
+ now += (tod_steering_delta < 0) ? (adj >> 15) : -(adj >> 15);
preempt_enable();
return now;
}
@@ -412,7 +411,7 @@ static void clock_sync_global(unsigned long long delta)
adj = tod_steering_end - now;
if (unlikely((s64) adj >= 0))
/* Calculate how much of the old adjustment is left. */
- tod_steering_delta = ((s64) tod_steering_delta < 0) ?
+ tod_steering_delta = (tod_steering_delta < 0) ?
-(adj >> 15) : (adj >> 15);
tod_steering_delta += delta;
if ((abs(tod_steering_delta) >> 48) != 0)