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Date:   Wed, 9 Jan 2019 11:31:26 +0000
From:   Catalin Marinas <catalin.marinas@arm.com>
To:     Prateek Patel <prpatel@nvidia.com>
Cc:     paul@paul-moore.com, sds@tycho.nsa.gov, eparis@parisplace.org,
        linux-kernel@vger.kernel.org, selinux@vger.kernel.org,
        linux-tegra@vger.kernel.org, talho@nvidia.com, swarren@nvidia.com,
        linux-mm@kvack.org, snikam@nvidia.com, vdumpa@nvidia.com,
        Sri Krishna chowdary <schowdary@nvidia.com>
Subject: Re: [PATCH] selinux: avc: mark avc node as not a leak
Message-ID: <20190109113126.nzpmb7xx4xqtn37w@mbp>
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Hi Prateek,

On Wed, Jan 09, 2019 at 02:09:22PM +0530, Prateek Patel wrote:
> From: Sri Krishna chowdary <schowdary@nvidia.com>
> 
> kmemleak detects allocated objects as leaks if not accessed for
> default scan time. The memory allocated using avc_alloc_node
> is freed using rcu mechanism when nodes are reclaimed or on
> avc_flush. So, there is no real leak here and kmemleak_scan
> detects it as a leak which is false positive. Hence, mark it as
> kmemleak_not_leak.

In theory, kmemleak should detect the node->rhead in the lists used by
call_rcu() and not report it as a leak. Which RCU options do you have
enabled (just to check whether kmemleak tracks the RCU internal lists)?

Also, does this leak eventually disappear without your patch? Does

  echo dump=0xffffffc0dd1a0e60 > /sys/kernel/debug/kmemleak

still display this object?

Thanks.

-- 
Catalin