Messages in this thread | | | Date | Tue, 31 May 2005 09:22:15 -0300 | From | Marcelo Tosatti <> | Subject | Re: potential-null-pointer-dereference-in-amiga-serial-driver.patch added to -mm tree |
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Hi Alexey,
On Tue, May 31, 2005 at 07:49:15PM +0400, Alexey Dobriyan wrote: > On Tuesday 31 May 2005 13:08, akpm@osdl.org wrote: > > A pointer is dereferenced before it is null-checked. > > > --- 25/drivers/char/amiserial.c~potential-null-pointer-dereference-in-amiga-serial-driver > > +++ 25-akpm/drivers/char/amiserial.c > > > static void rs_put_char(struct tty_struct *tty, unsigned char ch) > > { > > - struct async_struct *info = (struct async_struct *)tty->driver_data; > > + struct async_struct *info; > > unsigned long flags; > > > > + if (!tty) > > + return; > > Can ->put_char be ever called with tty being NULL? From my reading of > drivers/char/n_tty.c it can't.
Nope it can't, but the change makes the code more readable IMO, while handling a NULL "tty" argument properly (which the old version pretends to, but doesnt).
> Every single time ->put_char is used a-la > > tty->driver->put_char(tty, '\r'); > > So, tty will be dereferenced before function call. Same for static inline > put_char() there. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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