linux-kernel - Re: [RESEND PATCH v2] of: fix kmemleak crash caused by imbalance in early memory reservation

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Date:   Wed, 13 Feb 2019 18:30:12 +0200
From:   Mike Rapoport <rppt@...ux.ibm.com>
To:     Marc Gonzalez <marc.w.gonzalez@...e.fr>
Cc:     Rob Herring <robh+dt@...nel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Stephen Rothwell <sfr@...b.auug.org.au>,
        Frank Rowand <frowand.list@...il.com>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        Catalin Marinas <catalin.marinas@....com>,
        Prateek Patel <prpatel@...dia.com>,
        DT <devicetree@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        stable <stable@...r.kernel.org>
Subject: Re: [RESEND PATCH v2] of: fix kmemleak crash caused by imbalance in
 early memory reservation

On Wed, Feb 13, 2019 at 10:27:48AM +0100, Marc Gonzalez wrote:
> On 13/02/2019 07:57, Mike Rapoport wrote:
> 
> > Below is the version vs. current mmotm.
> > 
> > From 9ea6dceb46067d4f1cbbdbec1189c8496aa0a4bc Mon Sep 17 00:00:00 2001
> > From: Mike Rapoport <rppt@...ux.ibm.com>
> > Date: Mon, 4 Feb 2019 15:37:21 +0100
> > Subject: [PATCH] of: fix kmemleak crash caused by imbalance in early memory reservation
> 
> Out of curiosity, why don't you send as a proper v3?
 
Was too much in a hurry

> > Marc Gonzalez reported the following kmemleak crash:
> > 
> > [...]
> > 
> > The crash happens when a no-map area is allocated in
> > early_init_dt_alloc_reserved_memory_arch(). The allocated region is
> > registered with kmemleak, but it is then removed from memblock using
> > memblock_remove() that is not kmemleak-aware.
> > 
> > Replacing __memblock_alloc_base() with memblock_find_in_range()
> 
> Nit: in this new version, you're replacing memblock_phys_alloc_range()
> with memblock_find_in_range() so I don't know if the comment still
> applies.

and didn't check the outcome of blindly applying the patch :(

I'll send a proper v3 soon. Sorry for the noise.
 
> > makes sure that the allocated memory is not added to kmemleak and then
> > memblock_remove()'ing this memory is safe.
> > 
> > As a bonus, since memblock_find_in_range() ensures the allocation in the
> > specified range, the bounds check can be removed.
> > 
> > Cc: stable@...r.kernel.org # 3.15+
> > Fixes: 3f0c820664483 ("drivers: of: add initialization code for dynamic reserved memory")
> > Acked-by: Marek Szyprowski <m.szyprowski@...sung.com>
> > Acked-by: Prateek Patel <prpatel@...dia.com>
> > Tested-by: Marc Gonzalez <marc.w.gonzalez@...e.fr>
> > Signed-off-by: Mike Rapoport <rppt@...ux.ibm.com>
> 

-- 
Sincerely yours,
Mike.