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Date:   Fri, 11 Jan 2019 10:16:00 -0800
From:   Matthew Wilcox <willy@infradead.org>
To:     Qian Cai <cai@lca.pw>
Cc:     akpm@linux-foundation.org, esploit@protonmail.ch,
        jejb@linux.ibm.com, dgilbert@interlog.com,
        martin.petersen@oracle.com, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, walken@google.com,
        David.Woodhouse@intel.com
Subject: Re: [PATCH] rbtree: fix the red root
Message-ID: <20190111181600.GJ6310@bombadil.infradead.org>
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 <20190111165145.23628-1-cai@lca.pw>
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On Fri, Jan 11, 2019 at 01:12:36PM -0500, Qian Cai wrote:
> On Fri, 2019-01-11 at 09:31 -0800, Matthew Wilcox wrote:
> > On Fri, Jan 11, 2019 at 11:51:45AM -0500, Qian Cai wrote:
> > > Reported-by: Esme <esploit@protonmail.ch>
> > > Signed-off-by: Qian Cai <cai@lca.pw>
> > 
> > What change introduced this bug???We need a Fixes: line so the stable
> > people know how far to backport this fix.
> 
> It looks like,
> 
> Fixes: 6d58452dc06 (rbtree: adjust root color in rb_insert_color() only when
> necessary)
> 
> where it no longer always paint the root as black.
> 
> Also, copying this fix for the original author and reviewer.
> 
> https://lore.kernel.org/lkml/20190111165145.23628-1-cai@lca.pw/

Great, thanks!  We have a test-suite (lib/rbtree_test.c); could you add
a test to it that will reproduce this bug without your patch applied?