Messages in this thread |  | | | Date | Fri, 3 Jun 2005 04:58:16 -0300 | | From | Marcelo Tosatti <> | | Subject | Re: potential-null-pointer-dereference-in-amiga-serial-driver.patch added to -mm tree |
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On Wed, Jun 01, 2005 at 10:21:08PM -0700, Greg KH wrote: > On Tue, May 31, 2005 at 09:22:15AM -0300, Marcelo Tosatti wrote: > > > > 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). > > But unneeded checks like this are not encouraged in the kernel. As the > tty pointer can never be null, don't worry about it.
OK - so better just remove the check. Julien, care to follow Greg's recommendation and refresh the patch?
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