On Fri, Jan 03, 2020 at 04:12:07PM +0000, Sean Young wrote: > On Fri, Jan 03, 2020 at 04:02:42PM +0100, Johan Hovold wrote: > > On Sun, Dec 29, 2019 at 06:22:39PM +0100, Greg Kroah-Hartman wrote: > > > From: Yang Yingliang <yangyingliang@xxxxxxxxxx> > > > > > > [ Upstream commit 649cd16c438f51d4cd777e71ca1f47f6e0c5e65d ] > > > > > > If usb_set_interface() failed, iface->cur_altsetting will > > > not be assigned and it will be used in flexcop_usb_transfer_init() > > > It may lead a NULL pointer dereference. > > > > > > Check usb_set_interface() return value in flexcop_usb_init() > > > and return failed to avoid using this NULL pointer. > > > > > > Signed-off-by: Yang Yingliang <yangyingliang@xxxxxxxxxx> > > > Signed-off-by: Sean Young <sean@xxxxxxxx> > > > Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@xxxxxxxxxx> > > > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> > > > > This commit is bogus and should be dropped from all stable queues. > > > > Contrary to what the commit message claims, iface->cur_altsetting will > > never be NULL so there's no risk for a NULL-pointer dereference here. > > Yes, you are right, I can't find any path through which cur_altsetting > will be set to NULL. The commit message is wrong. I am sorry for letting > this slip through. > > Thank you for pointing this out. > > > Even though the change itself is benign, we shouldn't spread this > > confusion further. > > usb_set_interface() can fail for a number of reasons, and we should not > continue if it fails. So, the commit message is misleading but the > change itself is still valid. Sure, the change itself is fine, but I wouldn't consider it stable material even with a correct commit message as it is not a critical fix. And the user would still see an error message in case changing altsetting fails. Johan
