On Mon, Apr 03, 2023 at 09:12:55AM +0200, Geert Uytterhoeven wrote: > Hi Dan, > > On Mon, Apr 3, 2023 at 6:29 AM Dan Carpenter <error27@xxxxxxxxx> wrote: > > On Fri, Mar 31, 2023 at 02:13:10PM +0200, Geert Uytterhoeven wrote: > > > On Fri, Mar 31, 2023 at 12:14 PM Li Yang <lidaxian@xxxxxxxxxxx> wrote: > > > > Smatch reports: > > > > > > > > drivers/soc/renesas/renesas-soc.c:536 renesas_soc_init() warn: > > > > 'chipid' from ioremap() not released on lines: 475. > > > > > > > > If soc_dev_atrr allocation is failed, function renesas_soc_init() > > > > will return without releasing 'chipid' from ioremap(). > > > > > > > > Fix this by adding function iounmap(). > > > > > > > > Fixes: cb5508e47e60 ("soc: renesas: Add support for reading product revision for RZ/G2L family") > > > > Signed-off-by: Li Yang <lidaxian@xxxxxxxxxxx> > > > > Reviewed-by: Dan Carpenter <error27@xxxxxxxxx> > > > > > > Thanks for your patch! > > > > > > > --- a/drivers/soc/renesas/renesas-soc.c > > > > +++ b/drivers/soc/renesas/renesas-soc.c > > > > @@ -471,8 +471,11 @@ static int __init renesas_soc_init(void) > > > > } > > > > > > > > soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL); > > > > - if (!soc_dev_attr) > > > > + if (!soc_dev_attr) { > > > > + if (chipid) > > > > + iounmap(chipid); > > > > > > We don't really care, as the system is dead at this point anyway. > > > > Why even have the check for NULL then? The kzalloc() is small enough > > Because else someone will submit a patch to add that check? ;-) > > > to the point where it litterally cannot fail. > > I still don't understand how it can be guaranteed that small allocations > never fail... "while (1) kmalloc(16, GFP_KERNEL);" > I read an lwn article on it and I think I once looked it up to try figure out how small the definition of "small" was and it was surprisingly large... But I have no idea. I think maybe small atomic allocations can fail and GFP_KERNEL allocations sleep forever? (These guesses are worthless). > Perhaps we need a different mechanism to annotate error handling code > that cannot ever happen in a real product, so it can be thrown away by > the compiler, while still pleasing the static checkers? All these > checks and error handling code do affect kernel size. There are > Linux products running on SoCs with 8 MiB of internal SRAM. People sometimes call BUG_ON(!soc_dev_attr). It's sort of rare these days. It would be easy to make a function which silences Smatch... __system_is_dead(); regards, dan carpenter