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SubjectRe: UBSAN: Undefined behaviour in drivers/usb/core/devio.c:1517:25
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On 01/26/2016 06:25 PM, Alan Stern wrote:
> On Tue, 26 Jan 2016, Chris Bainbridge wrote:
>
>> Booting 4.5.0-rc1 with new UBSAN checker enabled:
>>
>> [ 4.556968] ================================================================================
>> [ 4.556972] UBSAN: Undefined behaviour in drivers/usb/core/devio.c:1517:25
>> [ 4.556975] shift exponent -1 is negative
>
> Does a left shift by a negative amount matter if the result isn't used?
>

By definition, any code with undefined behavior could do anything.
But in practice, undefined shift just leads to undefined result of shift operation
(it depends on operands and architecture).


> Alan Stern
>

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