Messages in this thread | | | Date | Mon, 20 Jun 2016 22:53:26 +0300 | From | Dan Carpenter <> | Subject | Re: [patch] ext4: underflow in alignment check |
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On Mon, Jun 20, 2016 at 06:02:04PM +0200, Jan Kara wrote: > On Thu 16-06-16 10:07:09, Dan Carpenter wrote: > > My static checker complains that this can underflow if arg is negative > > which is true. > > > > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> > > How come? (1 << 30) fits even into 32-bit signed type. So where's the > problem?
Bad changelog... I was talking about a different issue. I was casting it to unsigned to take advantage of type promototion. Assume we have:
int arg = 1 << 31;
(arg > (1 << 30)) // <-- this is false (arg > (1U << 30)) // <-- this is true so there is no underflow.
regards, dan carpenter
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