linux-kernel - Re: INFO: rcu detected stall in vprintk

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Date:   Tue, 26 Jun 2018 14:07:31 +0900
From:   Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
To:     Dmitry Vyukov <dvyukov@...gle.com>
Cc:     Steven Rostedt <rostedt@...dmis.org>,
        Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
        syzbot <syzbot+d29d18215e477cfbfbdd@...kaller.appspotmail.com>,
        LKML <linux-kernel@...r.kernel.org>,
        Petr Mladek <pmladek@...e.com>,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        syzkaller-bugs <syzkaller-bugs@...glegroups.com>,
        Samuel Ortiz <sameo@...ux.intel.com>,
        "David S. Miller" <davem@...emloft.net>,
        linux-wireless@...r.kernel.org, netdev <netdev@...r.kernel.org>
Subject: Re: INFO: rcu detected stall in vprintk_emit

On (06/26/18 07:03), Dmitry Vyukov wrote:
> > I don't think this is a printk() issue per se, so I think Option B is
> > the only option. You should not get stuck in an infinite loop if we run
> > short on memory. Perhaps we could have an Option C which would exit
> > this loop gracefully with some kind of error. But I haven't looked at
> > the surrounding code to be sure if that is possible.
> 
> I suspect this is not even OOM.

Could be. But at the same time it stalls RCU, so OOM at some point
becomes realistic.

	-ss