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

From: Fengguang Wu
Date: Thu Nov 30 2017 - 04:06:01 EST


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).

OK I'll try Dmitry's patch out.

Thanks,
Fengguang