timekeeping: Cast raw_interval to u64 to avoid shift overflow

commit 5b3900cd409466c0070b234d941650685ad0c791 upstream.

We fixed a bunch of integer overflows in timekeeping code during the 3.6
cycle.  I did an audit based on that and found this potential overflow.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: John Stultz <johnstul@us.ibm.com>
Link: http://lkml.kernel.org/r/20121009071823.GA19159@elgon.mountain
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[bwh: Backported to 3.2: adjust context; use timekeeper.raw_interval]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 5ee1ac096358c63a7eac31ca3f84efa9bbf73ba0..cb7f33e548b330fee6b0441c21e0c0d11568b807 100644 (file)
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -992,7 +992,7 @@ static cycle_t logarithmic_accumulation(cycle_t offset, int shift)
        }
 
        /* Accumulate raw time */
-       raw_nsecs = timekeeper.raw_interval << shift;
+       raw_nsecs = (u64)timekeeper.raw_interval << shift;
        raw_nsecs += raw_time.tv_nsec;
        if (raw_nsecs >= NSEC_PER_SEC) {
                u64 raw_secs = raw_nsecs;