linux-kernel - Re: [PATCH 4.9 75/95] random: set up the NUMA crng instances after the CRNG is fully initialized

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Message-ID: <20180423155637.GB8194@thunk.org>
Date:   Mon, 23 Apr 2018 11:56:37 -0400
From:   "Theodore Y. Ts'o" <tytso@....edu>
To:     Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>
Cc:     gregkh@...uxfoundation.org, ben@...adent.org.uk,
        linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        jannh@...gle.com, stable@...nel.org, carnil@...ian.org
Subject: Re: [PATCH 4.9 75/95] random: set up the NUMA crng instances after
 the CRNG is fully initialized

On Mon, Apr 23, 2018 at 07:21:10PM +0900, Tetsuo Handa wrote:
> Greg Kroah-Hartman wrote:
> > > I think this can be fixed by backporting commit 4a072c71f49b
> > > "random: silence compiler warnings and fix race" but I'm not sure
> > > whether that depends on other changes.
> > 
> > According to Tetsuo Handa, it's also causing problems in mainline :(
> > 
> > Ted, any thoughts as to what to do here?
> 
> (Resending because Webmail post was rejected by both stable ML and linux-kernel ML.)
> 
> Subject: random: GFP_KERNEL|__GFP_NOFAIL allocation from IRQ context
> 
> Hello.
> 
> Commit 8ef35c866f8862df ("random: set up the NUMA crng instances after
> the CRNG is fully initialized") is causing sleep inside atomic warning
> due to GFP_KERNEL|__GFP_NOFAIL allocation from IRQ context. Though it
> unlikely sleeps because there will be enough free memory at boot up...
> 
> Please don't backport that patch now.

Yes, please hold off on this in the stable queues as well.  What we'll
probably need to do is call defer the processing to a workqueue in the
CONFIG_NUMA case.

						- Ted