Messages in this thread Patch in this message |  | | Subject | [PATCH] prevent timespec/timeval to ktime_t overflow | | From | Thomas Gleixner <> | | Date | Wed, 30 Aug 2006 10:44:28 +0200 |
| |
Frank v. Waveren pointed out that on 64bit machines the timespec to ktime_t conversion might overflow. This is also true for timeval to ktime_t conversions. This breaks a "sleep inf" on 64bit machines.
While a timespec/timeval with tx.sec = MAX_LONG is valid by specification the internal representation of ktime_t is based on nanoseconds. The conversion of seconds to nanoseconds overflows for seconds values >= (MAX_LONG / NSEC_PER_SEC).
Check the seconds argument to the conversion and limit it to the maximum time which can be represented by ktime_t.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/include/linux/ktime.h b/include/linux/ktime.h index ed3396d..1beafb3 100644 --- a/include/linux/ktime.h +++ b/include/linux/ktime.h @@ -57,6 +57,7 @@ typedef union { } ktime_t; #define KTIME_MAX (~((u64)1 << 63)) +#define KTIME_SEC_MAX (KTIME_MAX / NSEC_PER_SEC) /* * ktime_t definitions when using the 64-bit scalar representation: @@ -73,6 +74,10 @@ typedef union { */ static inline ktime_t ktime_set(const long secs, const unsigned long nsecs) { +#if (BITS_PER_LONG == 64) + if (unlikely(secs >= KTIME_SEC_MAX)) + return (ktime_t){ .tv64 = KTIME_MAX }; +#endif return (ktime_t) { .tv64 = (s64)secs * NSEC_PER_SEC + (s64)nsecs }; }
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
|  |