Re: [patch] ext4: underflow in alignment check

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



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@xxxxxxxxxx>
> 
> 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

--
To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Index of Archives]     [Kernel Development]     [Kernel Announce]     [Kernel Newbies]     [Linux Networking Development]     [Share Photos]     [IDE]     [Security]     [Git]     [Netfilter]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Device Mapper]

  Powered by Linux