From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ve1eur01on0127.outbound.protection.outlook.com ([104.47.1.127]:3680 "EHLO EUR01-VE1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751643AbeFHO1i (ORCPT ); Fri, 8 Jun 2018 10:27:38 -0400 From: Konstantin Khorenko To: Kirill Gorkunov , Andrey Vagin , Benjamin Coddington , Jeff Layton , "J. Bruce Fields" , Alexander Viro Cc: Konstantin Khorenko , Vasily Averin , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/2] fs/lock: skip lock owner pid translation in case we are in init_pid_ns Date: Fri, 8 Jun 2018 17:27:11 +0300 Message-Id: <20180608142712.32460-2-khorenko@virtuozzo.com> In-Reply-To: <20180608142712.32460-1-khorenko@virtuozzo.com> References: <20180608142712.32460-1-khorenko@virtuozzo.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-fsdevel-owner@vger.kernel.org List-ID: 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: ================ (root@vz7)/: cat /proc/${PID_A2}/fdinfo/3 pos: 4 flags: 02100002 mnt_id: 257 lock: (root@vz7)/: After the patch: =============== (root@vz7)/:cat /proc/${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 for remote locks") Signed-off-by: Konstantin Khorenko --- fs/locks.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/fs/locks.c b/fs/locks.c index 05e211be8684..bfee5b7f2862 100644 --- a/fs/locks.c +++ b/fs/locks.c @@ -2072,6 +2072,13 @@ static pid_t locks_translate_pid(struct file_lock *fl, 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 == &init_pid_ns) + return (pid_t)fl->fl_pid; rcu_read_lock(); pid = find_pid_ns(fl->fl_pid, &init_pid_ns); -- 2.15.1