Hi Colin, On Tue, Sep 1, 2015 at 12:38 PM, Colin Ian King <[email protected]> wrote: > On 01/09/15 11:35, Geert Uytterhoeven wrote: >> On Tue, Sep 1, 2015 at 12:21 PM, Colin King <[email protected]> wrote: >>> On the unlikely event that drv is null, the current code will >>> perform a null pointer dereference with it when printing a dev_dbg >>> message. Instead, the BUG_ON check on drv should be performed >>> before we emit the dev_dbg message. >> >> What about just removing the BUG_ON()? >> >> The system will crash anyway, providing a backtrace. > > I personally think a BUG_ON() shows intention to try to catch an > unexpected issue in a standard way as opposed to just removing it and > then hitting an issue with a null ptr deference.
I think this BUG_ON() was purely used during development of the ps3_vuart framework. Note that the corresponding platform_drv_probe() also just dereferences its driver pointer. >>> Signed-off-by: Colin Ian King <[email protected]> >>> --- >>> drivers/ps3/ps3-vuart.c | 3 +-- >>> 1 file changed, 1 insertion(+), 2 deletions(-) >>> >>> diff --git a/drivers/ps3/ps3-vuart.c b/drivers/ps3/ps3-vuart.c >>> index d6db822..632701a 100644 >>> --- a/drivers/ps3/ps3-vuart.c >>> +++ b/drivers/ps3/ps3-vuart.c >>> @@ -1000,12 +1000,11 @@ static int ps3_vuart_probe(struct >>> ps3_system_bus_device *dev) >>> dev_dbg(&dev->core, "%s:%d\n", __func__, __LINE__); >>> >>> drv = ps3_system_bus_dev_to_vuart_drv(dev); >>> + BUG_ON(!drv); >>> >>> dev_dbg(&dev->core, "%s:%d: (%s)\n", __func__, __LINE__, >>> drv->core.core.name); >>> >>> - BUG_ON(!drv); >>> - >>> if (dev->port_number >= PORT_COUNT) { >>> BUG(); >>> return -EINVAL; Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected] In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
