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From:   Sasha Levin <Alexander.Levin@microsoft.com>
To:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "stable@vger.kernel.org" <stable@vger.kernel.org>
CC:     Vasily Averin <vvs@virtuozzo.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Hari Bathini <hbathini@linux.vnet.ibm.com>,
        Jiri Olsa <jolsa@redhat.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        "Namhyung Kim" <namhyung@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@kernel.org>,
        Sasha Levin <Alexander.Levin@microsoft.com>
Subject: [PATCH AUTOSEL for 4.14 090/100] perf/core: Fix memory leak triggered
 by perf --namespace
Thread-Topic: [PATCH AUTOSEL for 4.14 090/100] perf/core: Fix memory leak
 triggered by perf --namespace
Thread-Index: AQHTlMntsC0R2CNAkkaVhJWVJrKzOg==
Date:   Wed, 24 Jan 2018 04:15:12 +0000
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From: Vasily Averin <vvs@virtuozzo.com>

[ Upstream commit 0e18dd12064e07519f7cbff4149ca7fff620cbed ]

perf with --namespace key leaks various memory objects including namespaces

  4.14.0+
  pid_namespace          1     12   2568   12    8
  user_namespace         1     39    824   39    8
  net_namespace          1      5   6272    5    8

This happen because perf_fill_ns_link_info() struct patch ns_path:
during initialization ns_path incremented counters on related mnt and dentr=
y,
but without lost path_put nobody decremented them back.
Leaked dentry is name of related namespace,
and its leak does not allow to free unused namespace.

Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Hari Bathini <hbathini@linux.vnet.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: commit e422267322cd ("perf: Add PERF_RECORD_NAMESPACES to include na=
mespaces related info")
Link: http://lkml.kernel.org/r/c510711b-3904-e5e1-d296-61273d21118d@virtuoz=
zo.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
 kernel/events/core.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 24ebad5567b4..8c20af8738ac 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6756,6 +6756,7 @@ static void perf_fill_ns_link_info(struct perf_ns_lin=
k_info *ns_link_info,
 		ns_inode =3D ns_path.dentry->d_inode;
 		ns_link_info->dev =3D new_encode_dev(ns_inode->i_sb->s_dev);
 		ns_link_info->ino =3D ns_inode->i_ino;
+		path_put(&ns_path);
 	}
 }
=20
--=20
2.11.0