linux-kernel - Re: [PATCH] timer: silenct a lockdep splat with debugobjects

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Message-Id: <47A499D0-D1F5-4B72-A99D-6FBC8E3DD8AD@lca.pw>
Date:   Fri, 13 Mar 2020 22:53:24 -0400
From:   Qian Cai <cai@....pw>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        John Stultz <john.stultz@...aro.org>, sboyd@...nel.org,
        rostedt@...dmis.org, hannes@...xchg.org,
        linux-kernel@...r.kernel.org, Andy Lutomirski <luto@...capital.net>
Subject: Re: [PATCH] timer: silenct a lockdep splat with debugobjects



> On Mar 13, 2020, at 5:26 PM, Peter Zijlstra <peterz@...radead.org> wrote:
> 
> On Fri, Mar 13, 2020 at 05:00:41PM -0400, Qian Cai wrote:
>>> On Mar 13, 2020, at 4:13 PM, Peter Zijlstra <peterz@...radead.org> wrote:
> 
>>> 
>>> Or, fix that random crud to do the wakeup outside of the lock.
>> 
>> That is likely to be difficult until we can find a creative way to not “uglifying" the
>> random code by dropping locks in the middle etc just because of debugojects.
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/luto/linux.git/log/?h=random/fast
> 
> Doesn't look difficult at all.

Great. I cherry-picked the first two patches,

random: Consolidate entropy batches for u32 and u64
random: Remove batched entropy locking

which solved the issue here as well.

Andy, may I ask what your plan to post those?