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clockevents: Prevent shift out of bounds
Andrey reported that on a kernel with UBSan enabled he found: UBSan: Undefined behaviour in ../kernel/time/clockevents.c:75:34 I guess it should be 1ULL here instead of 1U: (!ismax || evt->mult <= (1U << evt->shift))) That's indeed the correct solution because shift might be 32. Reported-by: Andrey Ryabinin <a.ryabinin@samsung.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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@ -72,7 +72,7 @@ static u64 cev_delta2ns(unsigned long latch, struct clock_event_device *evt,
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* Also omit the add if it would overflow the u64 boundary.
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*/
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if ((~0ULL - clc > rnd) &&
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(!ismax || evt->mult <= (1U << evt->shift)))
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(!ismax || evt->mult <= (1ULL << evt->shift)))
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clc += rnd;
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do_div(clc, evt->mult);
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