Re: [PATCH] drivers/acpi/ec.c fix a small memory leak

Dan Carpenter
2010-02-03T06:12:41Z

On Tue, Feb 02, 2010 at 06:35:44PM +0300, Alexey Starikovskiy wrote:
> NAK
>
> saved_ec is allocated if flag EC_FLAGS_VALIDATE_ECDT is true.
> EC_FLAGS_SKIP_DSDT_SCAN have no sense in such case, thus this new code path
> is never executed.
> On the other hand, unconditionally freeing pointer, which is might be NULL, is not
> right either.

As near as I can tell you are right that the code cannot leak memory. But Darren
is right to think that it's calling kfree() on a NULL pointer is OK. His patch does
not introduce any errors.

The logic here is basically spaghetti. Every person who looks at it is going to
think it's a leak. Lots of people are going to look at it, because the static
checkers all think it's a leak too. Someone could send a cleanup patch that makes it
readable.

regards,
dan carpenter

> So, this patch introduced more problems as it tries to solve...
>
> Regards,
> Alex.
>
> Darren Jenkins пишет:
> > Plug a very small leak in acpi_ec_ecdt_probe()
> >
> > Coverity CID: 13319
> >
> > Signed-off-by: Darren Jenkins <darrenrjenkins@gmail.com>
> >
> > diff --git drivers/acpi/ec.c drivers/acpi/ec.c
> > index d6471bb..13061dc 100644
> > --- drivers/acpi/ec.c
> > +++ drivers/acpi/ec.c
> > @@ -1009,8 +1009,10 @@ int __init acpi_ec_ecdt_probe(void)
> > /* fall through */
> > }
> >
> > - if (EC_FLAGS_SKIP_DSDT_SCAN)
> > + if (EC_FLAGS_SKIP_DSDT_SCAN) {
> > + kfree(saved_ec);
> > return -ENODEV;
> > + }
> >
> > /* This workaround is needed only on some broken machines,
> > * which require early EC, but fail to provide ECDT */
> >
> >
>
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