Messages in this thread | | | Date | Mon, 12 Feb 2024 11:41:18 +0100 | From | Greg Kroah-Hartman <> | Subject | Re: [PATCH 3/3] mei: vsc: Assign pinfo fields in variable declaration |
| |
On Mon, Feb 12, 2024 at 11:14:29AM +0100, Arnd Bergmann wrote: > On Mon, Feb 12, 2024, at 11:02, Greg Kroah-Hartman wrote: > > On Mon, Feb 12, 2024 at 11:46:18AM +0200, Sakari Ailus wrote: > >> Assign all possible fields of pinfo in variable declaration, instead of > >> just zeroing it there. > >> > >> Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com> > >> --- > >> drivers/misc/mei/vsc-tp.c | 16 ++++++++-------- > >> 1 file changed, 8 insertions(+), 8 deletions(-) > >> > >> diff --git a/drivers/misc/mei/vsc-tp.c b/drivers/misc/mei/vsc-tp.c > >> index 200af14490d7..1eda2860f63b 100644 > >> --- a/drivers/misc/mei/vsc-tp.c > >> +++ b/drivers/misc/mei/vsc-tp.c > >> @@ -447,11 +447,16 @@ static int vsc_tp_match_any(struct acpi_device *adev, void *data) > >> > >> static int vsc_tp_probe(struct spi_device *spi) > >> { > >> - struct platform_device_info pinfo = { 0 }; > >> + struct vsc_tp *tp; > >> + struct platform_device_info pinfo = { > >> + .name = "intel_vsc", > >> + .data = &tp, > >> + .size_data = sizeof(tp), > >> + .id = PLATFORM_DEVID_NONE, > >> + }; > > > > But now you have potential stack data in the structure for the fields > > that you aren't assigning here, right? Is that acceptable, or will it > > leak somewhere? > > > > This is why we generally do not do this type of style. So unless you > > are fixing an issue here, please don't do it. > > If you have any initializer, all named fields in the structure > are zeroed. The only bits of the structure that may contain > stack data are for padding between fields, but that doesn't > actually change here from the previous version.
I thought we had looked into that before and it would 0 out everything if you just had the {0} initializer, including holes? Or was it not, or did it depend on the compiler/version? Sorry, I never remember and so just recommend a memset which should be the same overall.
> The old version you have here just skips the named fields > and otherwise would end up lookingn like > > struct platform_device_info pinfo = { > .parent = 0, > }; > > which is still a partial initializer and has the added > problem of relying on a literal '0' as a NULL pointer. > In modern compilers, one can write this as > struct platform_device_info pinfo = {}, but Sakari's > version looks best to me.
Ok, as long as there's no stale stack data, I'm ok with it.
thanks,
greg k-h
| |