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| author | Thomas Gleixner <tglx@linutronix.de> | 2007-04-09 00:03:30 +0200 |
|---|---|---|
| committer | Adrian Bunk <bunk@stusta.de> | 2007-04-09 00:03:30 +0200 |
| commit | 812b03dc31229847825989f5e35359a7c4dff6f4 (patch) | |
| tree | c684880491774be3b261f00f18e523dd0cb391d9 /include/linux | |
| parent | 2c461b3302b33de1500267a11cc50e29f33cbde6 (diff) | |
| download | lwn-812b03dc31229847825989f5e35359a7c4dff6f4.tar.gz lwn-812b03dc31229847825989f5e35359a7c4dff6f4.zip | |
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
time_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>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/ktime.h | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/include/linux/ktime.h b/include/linux/ktime.h index f3dec45ef874..f106701d7dbd 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: @@ -77,6 +78,10 @@ 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 }; } |