Re: [ 0.003333] BUG: KASAN: use-after-scope in console_unlock+0x605/0xcc0

Sergey Senozhatsky
2017-12-01T01:32:36Z

On (11/30/17 22:30), Fengguang Wu wrote:
> On Thu, Nov 30, 2017 at 05:29:09PM +0900, Sergey Senozhatsky wrote:
> > On (11/30/17 09:16), Dmitry Vyukov wrote:
> > [..]
> > > > to be honest, this backtrace hardly makes any sense to me.
> > > >
> > > > vprintk_emit()
> > > > reserve_standard_io_resources()
> > > > __flush_tlb_all()
> > > > vprintk_emit()
> > > > __down_trylock_console_sem()
> > > > wake_up_klogd()
> > > > console_unlock()
> > > >
> > > > I need some help here.
> > >
> > >
> > > You can try dirty patch from here:
> > > https://groups.google.com/d/msg/kasan-dev/iDb5bhcMBT0/55QzwWaHAwAJ
> > > It should make KASAN print the exact variable name and frame where it
> > > was allocated.
> >
> > would be good if Fengguang can try this out. I can't reproduce the
> > problem on my x86 box (linux-next and Linus's trees both work fine
> > for me with KASAN + lockdep + TRACE_IRQ).
>
> Attached is the dmesg with Dmitry's patch. The new output is:
>
> [ 0.003333] frame offset: 32
> [ 0.003333] desc: '2 32 4 3 __u 96 8 3 __u '
> [ 0.003333] func: console_unlock+0x0/0xcc0

thanks!

-ss