From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DB96CC4167D for ; Mon, 24 Jan 2022 22:29:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1586159AbiAXWZr (ORCPT ); Mon, 24 Jan 2022 17:25:47 -0500 Received: from dfw.source.kernel.org ([139.178.84.217]:49604 "EHLO dfw.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1453214AbiAXV26 (ORCPT ); Mon, 24 Jan 2022 16:28:58 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 320A9614DE; Mon, 24 Jan 2022 21:28:57 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0EA39C33E60; Mon, 24 Jan 2022 21:28:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1643059736; bh=UD6Ht1hPoWlejkDH/Gzpu/erG3jhCpBQYjkRtuiDRoM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NJqCFMmOABegN9HEYI4t/yZsW+cN3L/BxVaPY51UuS2I2CHL7Rw0S8SQJLS5TMhy/ omJSs6u29xr6bEvLFbi/or4bOqPXEIwllvJ+ObgIi627XlrxwXlMkt/idPapmLEdTr wnaspKGZW9HxYp11JGYqX9LezvEG37WnAwie6/Dg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Hangbin Liu , Jiri Olsa , Daniel Borkmann , Jussi Maki , Sasha Levin Subject: [PATCH 5.16 0716/1039] bpf/selftests: Fix namespace mount setup in tc_redirect Date: Mon, 24 Jan 2022 19:41:45 +0100 Message-Id: <20220124184149.401200286@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220124184125.121143506@linuxfoundation.org> References: <20220124184125.121143506@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jiri Olsa [ Upstream commit 5e22dd18626726028a93ff1350a8a71a00fd843d ] The tc_redirect umounts /sys in the new namespace, which can be mounted as shared and cause global umount. The lazy umount also takes down mounted trees under /sys like debugfs, which won't be available after sysfs mounts again and could cause fails in other tests. # cat /proc/self/mountinfo | grep debugfs 34 23 0:7 / /sys/kernel/debug rw,nosuid,nodev,noexec,relatime shared:14 - debugfs debugfs rw # cat /proc/self/mountinfo | grep sysfs 23 86 0:22 / /sys rw,nosuid,nodev,noexec,relatime shared:2 - sysfs sysfs rw # mount | grep debugfs debugfs on /sys/kernel/debug type debugfs (rw,nosuid,nodev,noexec,relatime) # ./test_progs -t tc_redirect #164 tc_redirect:OK Summary: 1/4 PASSED, 0 SKIPPED, 0 FAILED # mount | grep debugfs # cat /proc/self/mountinfo | grep debugfs # cat /proc/self/mountinfo | grep sysfs 25 86 0:22 / /sys rw,relatime shared:2 - sysfs sysfs rw Making the sysfs private under the new namespace so the umount won't trigger the global sysfs umount. Reported-by: Hangbin Liu Signed-off-by: Jiri Olsa Signed-off-by: Daniel Borkmann Cc: Jussi Maki Link: https://lore.kernel.org/bpf/20220104121030.138216-1-jolsa@kernel.org Signed-off-by: Sasha Levin --- tools/testing/selftests/bpf/prog_tests/tc_redirect.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/tc_redirect.c b/tools/testing/selftests/bpf/prog_tests/tc_redirect.c index 4b18b73df10b6..c2426df58e172 100644 --- a/tools/testing/selftests/bpf/prog_tests/tc_redirect.c +++ b/tools/testing/selftests/bpf/prog_tests/tc_redirect.c @@ -105,6 +105,13 @@ static int setns_by_fd(int nsfd) if (!ASSERT_OK(err, "unshare")) return err; + /* Make our /sys mount private, so the following umount won't + * trigger the global umount in case it's shared. + */ + err = mount("none", "/sys", NULL, MS_PRIVATE, NULL); + if (!ASSERT_OK(err, "remount private /sys")) + return err; + err = umount2("/sys", MNT_DETACH); if (!ASSERT_OK(err, "umount2 /sys")) return err; -- 2.34.1