linux-kernel - Re: possible deadlock in console

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Message-ID: <20190218054649.GA26686@jagdpanzerIV>
Date:   Mon, 18 Feb 2019 14:46:49 +0900
From:   Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
To:     Yao HongBo <yaohongbo@...wei.com>
Cc:     Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        linuxarm@...wei.com, linux-kernel@...r.kernel.org
Subject: Re: possible deadlock in console_unlock

Hi,

On (02/16/19 15:59), Yao HongBo wrote:
> > GFP_NOWARN is probably the best option for now. Yes, it, maybe,
> > will not work for fault-injection cases; but printk_safe approach
> > is harder to push for, especially given that printk_safe maybe will
> > not even exist in the future.
> 
> I have tried GFP_NOWARN, but the problem still exists.
> Only print_safe contexts for tty locks can solve the problem.
> My test scenario is falt-injection.

Oh, I see. Yes, fault-injection is special.

I suspect that this patch series can be helpful then
https://lore.kernel.org/lkml/20181016050428.17966-1-sergey.senozhatsky@gmail.com/T/#u

but first we need to figure out if printk_safe will
stay in the kernel (this will take some time).

	-ss