Re: [syzbot] possible deadlock in console_lock_spinning_enable (2)

Sergey Senozhatsky
2022-06-20T09:24:27Z

On (22/06/20 10:16), Dmitry Vyukov wrote:
> On Mon, 20 Jun 2022 at 07:44, Sergey Senozhatsky
> <senozhatsky@chromium.org> wrote:
> >
> > On (22/06/18 20:47), syzbot wrote:
> > > syzbot suspects this issue was fixed by commit:
> > >
> > > commit faebd693c59387b7b765fab64b543855e15a91b4
> > > Author: John Ogness <john.ogness@linutronix.de>
> > > Date: Thu Apr 21 21:22:36 2022 +0000
> > >
> > > printk: rename cpulock functions
> >
> > I'd rather guess that it was console kthread patch that fixed the problem.
>
> Hi Sergey,
>
> Do you mean this commit:
>
> author: John Ogness 2022-04-21 23:28:48 +0206
> printk: add kthread console printers
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=09c5ba0aa2fcfdadb17d045c3ee6f86d69270df7

Yes, I'd assume so. The patch removes

tty -> printk -> tty

which re-enters tty in unsafe manner, and replaces it with

tty -> printk -> wake_up console printer