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Date:   Tue, 7 Sep 2021 08:23:54 +0100
From:   Catalin Marinas <catalin.marinas@arm.com>
To:     Naohiro Aota <naohiro.aota@wdc.com>
Cc:     linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
        linux-kernel@vger.kernel.org,
        "Darrick J . Wong" <djwong@kernel.org>, linux-xfs@vger.kernel.org
Subject: Re: [PATCH] mm/kmemleak: allow __GFP_NOLOCKDEP passed to kmemleak's
 gfp
Message-ID: <YTcTinqat08VK+xP@arm.com>
References: <20210907055659.3182992-1-naohiro.aota@wdc.com>
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On Tue, Sep 07, 2021 at 02:56:59PM +0900, Naohiro Aota wrote:
> In a memory pressure situation, I'm seeing the lockdep WARNING below.
> Actually, this is similar to a known false positive which is already
> addressed by commit 6dcde60efd94 ("xfs: more lockdep whackamole with
> kmem_alloc*").
> 
> This warning still persists because it's not from kmalloc() itself but
> from an allocation for kmemleak object. While kmalloc() itself suppress
> the warning with __GFP_NOLOCKDEP, gfp_kmemleak_mask() is dropping the
> flag for the kmemleak's allocation.
> 
> Allow __GFP_NOLOCKDEP to be passed to kmemleak's allocation, so that the
> warning for it is also suppressed.
> 
>   ======================================================
>   WARNING: possible circular locking dependency detected
>   5.14.0-rc7-BTRFS-ZNS+ #37 Not tainted

Acked-by: Catalin Marinas <catalin.marinas@arm.com>