Re: [RFC][PATCHv2 5/8] sysrq: switch to printk.emergency mode in unsafe places

From: Sergey Senozhatsky
Date: Fri Mar 31 2017 - 20:06:11 EST


Hello,

On (03/31/17 17:37), Petr Mladek wrote:
> On Wed 2017-03-29 18:25:08, Sergey Senozhatsky wrote:
> > It's not always possible/safe to wake_up() printk kernel
> > thread from sysrq (theoretically). Thus we better switch
> > printk() to emergency mode in some of the sysrq handlers,
> > which allows us to immediately flush pending kernel message
> > to the console.
> >
> > Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
> > Suggested-by: Tetsuo Handa <penguin-kernel@xxxxxxxxxxxxxxxxxxx>
>
> It looks like a decent selection. It is pity that some of
> them might produce rather long output and theoretically
> cause a softlookup. But I do not know about a better solution
> at the moment. In each case, it will not be worse than before
> this patchset.

thanks.

this patch will be replaced with a more 'generic' one, which
I posted in reply yo Ye Xiaolong's report.

-ss