KASAN: slab-out-of-bounds Read in fbcon_get_font

[Dmitry Vyukov]

On Thu, Dec 5, 2019 at 11:41 AM Tetsuo Handa
<penguin-kernel at i-love.sakura.ne.jp> wrote:
>
> On 2019/12/05 19:22, Paolo Bonzini wrote:
> > Ah, and because the machine is a KVM guest, kvm_wait appears in a lot of
> > backtrace and I get to share syzkaller's joy every time. :)
> >
> > This bisect result is bogus, though Tetsuo found the bug anyway.
> > Perhaps you can exclude commits that only touch architectures other than
> > x86?
> >
>
> It would be nice if coverage functionality can extract filenames in the source
> code and supply the list of filenames as arguments for bisect operation.
>
> Also, (unrelated but) it would be nice if we can have "make yes2modconfig"
> target which converts CONFIG_FOO=y to CONFIG_FOO=m if FOO is tristate.
> syzbot is testing kernel configs close to "make allyesconfig" but I want to
> save kernel rebuild time by disabling unrelated functionality when manually
> "debug printk()ing" kernels.

I thought that maybe sed "s#=y#=m#g" && make olddefconfig will do, but
unfortunately, it turns off non-tristate configs...

$ egrep "CONFIG_MEMORY_HOTPLUG|CONFIG_TCP_CONG_DCTCP" .config
CONFIG_MEMORY_HOTPLUG=y
CONFIG_TCP_CONG_DCTCP=y
# sed -i "s/CONFIG_MEMORY_HOTPLUG=y/CONFIG_MEMORY_HOTPLUG=m/g" .config
# sed -i "s/CONFIG_TCP_CONG_DCTCP=y/CONFIG_TCP_CONG_DCTCP=m/g" .config
# egrep "CONFIG_MEMORY_HOTPLUG|CONFIG_TCP_CONG_DCTCP" .config
CONFIG_MEMORY_HOTPLUG=m
CONFIG_TCP_CONG_DCTCP=m
# make olddefconfig
# egrep "CONFIG_MEMORY_HOTPLUG|CONFIG_TCP_CONG_DCTCP" .config
# CONFIG_MEMORY_HOTPLUG is not set
CONFIG_TCP_CONG_DCTCP=m