From 96dd7421a06a5bc6eb731323b95efcb2fd864854 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 6 Sep 2006 00:03:42 -0700 Subject: [PATCH] [PATCH] prevent timespec/timeval to ktime_t overflow 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 Cc: Ingo Molnar Cc: Frank v Waveren Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/ktime.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/include/linux/ktime.h b/include/linux/ktime.h index ed3396dcc4..84eeecd60a 100644 --- a/include/linux/ktime.h +++ b/include/linux/ktime.h @@ -56,7 +56,8 @@ typedef union { #endif } ktime_t; -#define KTIME_MAX (~((u64)1 << 63)) +#define KTIME_MAX ((s64)~((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 }; } -- 2.39.5