From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-eopbgr690116.outbound.protection.outlook.com ([40.107.69.116]:54124 "EHLO NAM04-CO1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1730540AbeIQIaa (ORCPT ); Mon, 17 Sep 2018 04:30:30 -0400 From: Sasha Levin To: "stable@vger.kernel.org" , "linux-kernel@vger.kernel.org" CC: Konstantin Khorenko , Jeff Layton , Sasha Levin Subject: [PATCH AUTOSEL 4.14 83/87] fs/lock: skip lock owner pid translation in case we are in init_pid_ns Date: Mon, 17 Sep 2018 03:03:17 +0000 Message-ID: <20180917030220.245686-83-alexander.levin@microsoft.com> References: <20180917030220.245686-1-alexander.levin@microsoft.com> In-Reply-To: <20180917030220.245686-1-alexander.levin@microsoft.com> Content-Language: en-US Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org List-ID: From: Konstantin Khorenko [ Upstream commit 826d7bc9f013d01e92997883d2fd0c25f4af1f1c ] If the flock owner process is dead and its pid has been already freed, pid translation won't work, but we still want to show flock owner pid number when expecting /proc/$PID/fdinfo/$FD in init pidns. Reproducer: process A process A1 process A2 fork()---------> exit() open() flock() fork()---------> exit() sleep() Before the patch: =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D (root@vz7)/: cat /proc/${PID_A2}/fdinfo/3 pos: 4 flags: 02100002 mnt_id: 257 lock: (root@vz7)/: After the patch: =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D (root@vz7)/:cat /proc/${PID_A2}/fdinfo/3 pos: 4 flags: 02100002 mnt_id: 295 lock: 1: FLOCK ADVISORY WRITE ${PID_A1} b6:f8a61:529946 0 EOF Fixes: 9d5b86ac13c5 ("fs/locks: Remove fl_nspid and use fs-specific l_pid f= or remote locks") Signed-off-by: Konstantin Khorenko Acked-by: Andrey Vagin Reviewed-by: Benjamin Coddington Signed-off-by: Jeff Layton Signed-off-by: Sasha Levin --- fs/locks.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/fs/locks.c b/fs/locks.c index 1bd71c4d663a..665e3ce9ab47 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -2074,6 +2074,13 @@ static pid_t locks_translate_pid(struct file_lock *f= l, struct pid_namespace *ns) return -1; if (IS_REMOTELCK(fl)) return fl->fl_pid; + /* + * If the flock owner process is dead and its pid has been already + * freed, the translation below won't work, but we still want to show + * flock owner pid number in init pidns. + */ + if (ns =3D=3D &init_pid_ns) + return (pid_t)fl->fl_pid; =20 rcu_read_lock(); pid =3D find_pid_ns(fl->fl_pid, &init_pid_ns); --=20 2.17.1