timekeeping: Cast raw_interval to u64 to avoid shift overflow
Dan Carpenter [Tue, 9 Oct 2012 07:18:23 +0000 (10:18 +0300)]
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>
Cc: Ben Hutchings <ben@decadent.org.uk>
[ herton: adapt for 3.5, timekeeper instead of tk pointer ]
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

kernel/time/timekeeping.c

index 12843e9..eff0b1e 100644 (file)
@@ -1014,7 +1014,7 @@ 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 += timekeeper.raw_time.tv_nsec;
        if (raw_nsecs >= NSEC_PER_SEC) {
                u64 raw_secs = raw_nsecs;