Re: [PATCH] staging: android: ion: hisilicon: Use pointer to memory being allocated as the sizeof argument

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Wed, Sep 21, 2016 at 10:01:09PM +0530, sayli karnik wrote:
> On Wed, Sep 21, 2016 at 9:45 PM, Greg Kroah-Hartman
> <gregkh@linuxfoundation.org> wrote:
> > On Wed, Sep 21, 2016 at 09:11:14PM +0530, sayli karnik wrote:
> >> This patch finds cases where the argument to sizeof is wrong in memory
> >> allocation functions by checking the type of the allocated memory when it is a
> >> double pointer and ensuring the sizeof argument takes a pointer to the memory
> >> being allocated.
> >
> > Are you sure?
> >
> This was detected by scripts/coccinelle/misc/badty.cocci, which
> specifies that a false positive only arises when the sizeof argument
> is not used in constructing the return value. Also the driver builds
> without errors. What do you think?

building without errors is not the issue here at all, it's a number that
is being passed in, you could replace that statement with "42" and it
would still build.

But would it work when running?  That's the question here :)

Please look at the surrounding code and see if it is correct or not,
somehow it is working as-is, right?  Are we just allocating too much
memory?

Pointer math is tricky at times, I can understand coccinelle scripts
getting confused here...

thanks,

greg k-h