[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 <tglx@linutronix.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: Frank v Waveren <fvw@var.cx> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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@ -56,7 +56,8 @@ typedef union {
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#endif
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} ktime_t;
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#define KTIME_MAX (~((u64)1 << 63))
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#define KTIME_MAX ((s64)~((u64)1 << 63))
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#define KTIME_SEC_MAX (KTIME_MAX / NSEC_PER_SEC)
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/*
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* ktime_t definitions when using the 64-bit scalar representation:
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@ -73,6 +74,10 @@ typedef union {
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*/
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static inline ktime_t ktime_set(const long secs, const unsigned long nsecs)
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{
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#if (BITS_PER_LONG == 64)
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if (unlikely(secs >= KTIME_SEC_MAX))
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return (ktime_t){ .tv64 = KTIME_MAX };
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#endif
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return (ktime_t) { .tv64 = (s64)secs * NSEC_PER_SEC + (s64)nsecs };
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}
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