Re: [PATCH v2] nvmem: core: fix possibly memleak when use nvmem_cell_info_to_nvmem_cell()

Vadym Kochan
2020-09-23T16:02:35Z

On Wed, Sep 23, 2020 at 04:51:06PM +0100, Srinivas Kandagatla wrote:
>
>
> On 23/09/2020 15:51, Vadym Kochan wrote:
> > > - return nvmem_cell_write(&cell, buf, cell.bytes);
> > > + rc = nvmem_cell_write(&cell, buf, cell.bytes);
> > > + if (rc)
> > > + kfree_const(cell->name);
> > > +
> > > + return rc;
> > > }
> > > EXPORT_SYMBOL_GPL(nvmem_device_cell_write);
> > > ------------------------>cut<---------------------------
> > >
> > > --srini
> > >
> > But is it really needed to kstrdup(cell->name) for nvmem_device_cell_{read,write} ?
> This boils down to if we want to use same api to parse nvmem_cell_info or
> not!
>
> If we want to keep this simple, we can either explicitly add free for
> successful caller to nvmem_cell_info_to_nvmem_cell()!
>

I think that such additional kfree_const(cell->name) handling adds more
complexity for error handling, also to my understanding usually
resource allocation should be done in the called func in case of error
was returned.

> Or
>
> use something like what you did, but new api needs more clarity!
> May be renaming __nvmem_cell_info_to_nvmem_cell to
> nvmem_cell_info_to_nvmem_cell_no_alloc would clarify that a bit!
>

Yes, I agree that naming should be better, actually "__" already points
to it's unsafety (no kstrdup() is used), but of course additional suffix
would be better.

> Also can you make sure that linewrapping on function names be inline with
> existing code.

You mean do not do such func attributes breaking as I did (moved them
line upper) ?

>
> Please send v3 with that changes!
>
>
> --srini
> > It is used only for log error in case the unaligned access did not
> > pass the check