Re: [syzbot] [kernel?] possible deadlock in console_flush_all (2)

From: Tetsuo Handa
Date: Wed Mar 27 2024 - 11:39:32 EST


On 2024/03/27 20:05, John Ogness wrote:
> The printk rework (which is not yet fully mainline) will correctly
> handle this context.
>
> As to the patch [0] you suggested, it would be more appropriate to
> perform deferred_enter/_exit *within* the locked critical section. But
> we really only want these whack-a-mole workarounds for cases that can
> occur in a non-bug situation. IMHO this is not such a case and falls
> into the category of "known problem, the rework will handle it".
>
> John Ogness
>
> [0] https://syzkaller.appspot.com/text?tag=Patch&x=121c92fe180000
>

Since the cause of current flood of lockdep reports is already explained
in https://syzkaller.appspot.com/bug?extid=c4f4d25859c2e5859988 , we don't
need [0] for now. But it is unfortunate that the message which explains
what went wrong cannot be reported due to reporting console_lock dependency.
Therefore, I intend [0] as a workaround for a bug situation. We can revert [0]
after the printk rework completed.