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Subject: Re: slub: BUG: Invalid wait context
To:     Matthew Wilcox <willy@infradead.org>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Christoph Lameter <cl@linux.com>,
        Linux Memory Management List <linux-mm@kvack.org>
References: <3b7661a1-dbde-ea54-f880-99777c95ae22@kernel.dk>
 <YTEeTK83KNBmuJLC@casper.infradead.org>
 <91af18d0-64cb-71ac-e9f4-4135fe02cb33@kernel.dk>
 <YTEf2MEkEdMVAuRF@casper.infradead.org>
From:   Jens Axboe <axboe@kernel.dk>
Message-ID: <4b884d2b-bcac-4967-d792-f7653084c38d@kernel.dk>
Date:   Thu, 2 Sep 2021 13:05:31 -0600
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On 9/2/21 1:02 PM, Matthew Wilcox wrote:
> On Thu, Sep 02, 2021 at 12:59:33PM -0600, Jens Axboe wrote:
>> On 9/2/21 12:56 PM, Matthew Wilcox wrote:
>>> On Thu, Sep 02, 2021 at 10:22:23AM -0600, Jens Axboe wrote:
>>>> Hi,
>>>>
>>>> Booting current -git yields the below splat. I'm assuming this is
>>>> related to the new RT stuff, where spin_lock() can sleep. This obviously
>>>> won't fly off IPI.
>>>
>>> You want to turn off PROVE_RAW_LOCK_NESTING for the moment.
>>
>> Because?
> 
>         help
>          Enable the raw_spinlock vs. spinlock nesting checks which ensure
>          that the lock nesting rules for PREEMPT_RT enabled kernels are
>          not violated.
> 
>          NOTE: There are known nesting problems. So if you enable this
>          option expect lockdep splats until these problems have been fully
>          addressed which is work in progress. This config switch allows to
>          identify and analyze these problems. It will be removed and the
>          check permanently enabled once the main issues have been fixed.
> 
>          If unsure, select N.

This isn't a new text, it's been like that for quite a while. The warning
is new on -git with that option.

-- 
Jens Axboe