On Thu, 19 Oct 2017, Paul Bolle wrote:
> On Thu, 2017-10-19 at 23:03 +0200, Paul Bolle wrote:
> > On Mon, 2017-10-16 at 17:29 -0700, Kees Cook wrote:
> > > In preparation for unconditionally passing the struct timer_list pointer
> > > to
> > > all timer callbacks, switch to using the new timer_setup() and
> > > from_timer()
> > > to pass the timer pointer explicitly.
> >
> > Acked-by: Paul Bolle <pebo...@tiscali.nl>
>
> I have to take this back, sorry!
>
> > For the record: this patch made me nervous but survived the rigorous
> > testing I
> > threw at it. (Ie, dialing up using bas_gigaset and downloading almost 20 MB
> > in
> > just over an hour. Whoot! That's more than good enough to ack this patch.)
> >
> > There was some cleanup I had in mind to make this patch more
> > straightforward.
> > But that can wait until someone finds a way to hit an issue with this patch.
> > We'll see.
>
> That someone turns out to be me, doing "modprobe -r bas_gigaset":
>
> <1>[30143.538135] BUG: unable to handle kernel NULL pointer dereference at
> 000001e9
> <1>[30143.538154] IP: mutex_lock+0x19/0x30
> <0>[30143.538300] gigaset_shutdown+0x28/0x130 [gigaset]
> <0>[30143.538307] ? find_module_all+0x62/0x80
> <0>[30143.538314] bas_gigaset_exit+0x31/0x1077 [bas_gigaset]
bas_gigaset_exit()
{
for (i = 0; i < driver->minors; i++) {
if (gigaset_shutdown(driver->cs + i) < 0)
gigaset_shutdown(cs)
{
mutex_lock(&cs->mutex); <-------- Explodes here
So driver->cs + i is invalid. No idea how that might be related to that
timer conversion patch, but ....
Thanks,
tglx
