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Subject: Re: [PATCH] lost path_put in perf_fill_ns_link_info
To: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: linux-kernel@vger.kernel.org,
        Hari Bathini <hbathini@linux.vnet.ibm.com>,
        Namhyung Kim <namhyung@kernel.org>, Jiri Olsa <jolsa@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Ingo Molnar <mingo@redhat.com>, Peter Zijlstra <peterz@infradead.org>
References: <c15b71b7-b835-bb48-d459-e553217a003d@virtuozzo.com>
 <20171108120915.n7i46j2yly6fb7bj@ukko.fi.intel.com>
From: Vasily Averin <vvs@virtuozzo.com>
Message-ID: <2d0707fa-7265-8b82-23a0-b3a938111767@virtuozzo.com>
Date: Wed, 8 Nov 2017 16:04:47 +0300
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On 2017-11-08 15:09, Alexander Shishkin wrote:
> On Mon, Nov 06, 2017 at 09:22:18AM +0300, Vasily Averin wrote:
>> Fixes: commit e422267322cd ("perf: Add PERF_RECORD_NAMESPACES to include namespaces related info")
>> Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
> 
> The change description is missing. One needs to open the source code and
> look for proof of correctness for this patch.

perf_fill_ns_link_info() calls ns_get_path()
it returns ns_path with increased mnt and dentry counters.

Problem is that nodody decrement these counters.

You can call ./perf record --namespaces unshare -m
and look how grows mount counter on nsfs_mnt.