On 12/21/05, Alessandro Zummo <[email protected]> wrote:
> On Tue, 20 Dec 2005 21:01:39 -0500
> Dmitry Torokhov <[email protected]> wrote:
>
>
> > > +if (ops->read_time) {
> > > +memset(tm, 0, sizeof(struct rtc_time));
> > >
> >
> > What guarantees that ops is not NULL here? Userspace can keep the
> > attribute (file) open and issue read after class_device was unregistered
> > and devdata set to NULL.
>
> Right. For /proc and /dev there's a try_module_get(ops->owner) in place.
>
> Should I add it to every rtc_sysfs_show_xxx or there's
> a better way to do it?
>
Well, I don't know what will it buy you: if ops is NULL
try_module_get(ops->owner) will OOPS just as happily as original code.
Your class_device has to hold on to all data structures that are
referenced from sysfs attributes untils its ->release() function is
called. Alternatively you could stuck a mutex and a flag somewhere in
driver data and take it when unregistering class device and also in
all attributes (and chech the flag there).
--
Dmitry
-
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/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
