* Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:
> On Thu, 2017-12-28 at 11:28 +0100, Ingo Molnar wrote:
> > * Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:
> >
> > > The annoying static analyzer follow up patches make a pain rather
> > > then
> > > fixing issues.
> > >
> > > The one done by commit 276c87054751
> > >
> > > ("x86/platform/intel-mid: Make 'bt_sfi_data' const")
> > >
> > > made an obvious regression [BugLink] since the struct bt_sfi_data
> > > used
> > > as a temporary container for important data that is used to fill
> > > 'parent' and 'name' fields in struct platform_device_info.
> > >
> > > That's why revert the commit which had been apparently done w/o
> > > reading
> > > the code.
> > >
> > > BugLink: https://github.com/andy-shev/linux/issues/20
> > > Cc: Bhumika Goyal <bhumirks@xxxxxxxxx>
> > > Cc: julia.lawall@xxxxxxx
> > > Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> > > ---
> > > arch/x86/platform/intel-mid/device_libs/platform_bt.c | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/arch/x86/platform/intel-mid/device_libs/platform_bt.c
> > > b/arch/x86/platform/intel-mid/device_libs/platform_bt.c
> > > index dc036e511f48..5a0483e7bf66 100644
> > > --- a/arch/x86/platform/intel-mid/device_libs/platform_bt.c
> > > +++ b/arch/x86/platform/intel-mid/device_libs/platform_bt.c
> > > @@ -60,7 +60,7 @@ static int __init tng_bt_sfi_setup(struct
> > > bt_sfi_data *ddata)
> > > return 0;
> > > }
> > >
> > > -static const struct bt_sfi_data tng_bt_sfi_data __initdata = {
> > > +static struct bt_sfi_data tng_bt_sfi_data __initdata = {
> > > .setup = tng_bt_sfi_setup,
> > > };
> >
> > This is nasty, why didn't the compiler warn about this bug?
> >
> > Normally when using a const data structure for a non-const purpose.
> > (Unless
> > there's a type cast which loses the type - one of the many reasons why
> > type casts
> > should be avoided.)
>
> Now I'm trying to get this.
>
> First of all, the new dependency to hci_bcm makes this one not compiled
> at all.
>
> Second, there is a cast as you truthfully predicted...
>
> I would say that revert is needed, but it seems it wasn't a culprit for
> the bug (rather the new dependency is). So, it might need rewording of
> the commit message to low tone of the accusations.
Your fix is absolutely needed and welcome, but I'd first like to see a build error
or build warning that avoids the introduction of this class of problems in the
future - then apply your fix in a separate patch.
Constification patches are useful in general, and such breakages are hard to debug
...
Thanks,
Ingo
