Date:   Tue, 24 Jan 2023 13:23:42 -0800
From:   Isaac Manjarres <isaacmanjarres@google.com>
To:     Andrew Morton <akpm@linux-foundation.org>
Cc:     Catalin Marinas <catalin.marinas@arm.com>,
        Saravana Kannan <saravanak@google.com>,
        Suren Baghdasaryan <surenb@google.com>,
        kernel-team@android.com, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1 0/2] Fixes for kmemleak tracking with CMA regions
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 <20230124122015.9f4e93e197153183085afbff@linux-foundation.org>
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On Tue, Jan 24, 2023 at 12:20:15PM -0800, Andrew Morton wrote:
> On Tue, 24 Jan 2023 15:48:57 +0000 Catalin Marinas <catalin.marinas@arm.com> wrote:
> 
> > Thanks for digging this out. This patch shouldn't have ended up upstream
> > (commit 972fa3a7c17c "mm: kmemleak: alloc gray object for reserved
> > region with direct map"). I thought both Calvin Zhang and I agreed that
> > it's not the correct approach (not even sure there was a real problem to
> > fix).
> > 
> > Do you still get the any faults with the above commit reverted? I'd
> > prefer this if it works rather than adding unnecessary
> > kmemleak_alloc/free callbacks that pretty much cancel each-other.
> > 
> > > I'm not sure if that commit is appropriate, given that reserved regions
> > > that still have their direct mappings intact may be used for DMA, which
> > > isn't appropriate for kmemleak scanning.
> > 
> > It's not. I think it should be reverted.
> 
> Could someone please send along a patch to revert this, along
> with the explanation for doing so?  And please consider a cc:stable.
Yes, I can send a revert patch later today. My patches that are
currently in mm-unstable depend on this patch though, so those would
have to be dropped from that branch as well.

--Isaac