From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C95B911702 for ; Wed, 25 Oct 2023 05:42:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="V67brfH4" Received: from mail-pf1-x431.google.com (mail-pf1-x431.google.com [IPv6:2607:f8b0:4864:20::431]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1094912A for ; Tue, 24 Oct 2023 22:42:03 -0700 (PDT) Received: by mail-pf1-x431.google.com with SMTP id d2e1a72fcca58-6be840283ceso4364044b3a.3 for ; Tue, 24 Oct 2023 22:42:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1698212522; x=1698817322; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=/4I6K4dn8jNN6gYXvsKkaB5Cz2wUpBzr4i6+0y5JHBs=; b=V67brfH4axm1VYI8Rvys6ni5ZKUMHczSpX+Q+yzx3uZqtSePRkNRQWSTbOS2H4TI/k xrZiNtors0N/vJP2FHJbwYeptWo1hjUO/ZnzxR0onkV3dFejGlIPZwEG2uI3SA62g69x p6sKdPLxpEwWCAXHDXQyZKJdBoGHqLL+ZhcIEezQ3nilKNK3nH8UopywH9pwK4OSnXK3 7cqtjTVb3d6MC0mMqggkb3KDeR3oSHBxisHzw8zgOCmrdKt+5334x7fpaqqtfK/XoAf0 LESWcqGqEswqwQ1ZirOia3TqlahTnKkyu5DQHOlV1NGHbHYBQbKrENN+J6lmSnPZ0w9q /iqQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1698212522; x=1698817322; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=/4I6K4dn8jNN6gYXvsKkaB5Cz2wUpBzr4i6+0y5JHBs=; b=jfQH8MjkxwK87yBHiH0U39BJTqcfKdr1umEZf7SE7qM0mqyTXeoj+M4fqaW4d957j/ VpenCJsqtHQxRCMC2MJSOFeLBJbNiXfpGsEyJhL0Mcjl4ZV1C3/RY4FyXsGMPljW1WXD pbuT/EwDmvwxduUjEyg7XD/lv+thx6WY72C2yrWkL/05uZYbBliycWh67hCEykL/kOE9 TW1aTXy4jaa+23jLfJ6Wub/ShZn++nk1WLdnY0wX51/XrTdOx6Xcamq3iXRYXXEgXlYi GhJ+o5R3upRhQG5rx37PO7MYCMPuCQQ4Cegrwqp1fEMNSMRYGaPD7FWlKMYAPXn68Fi/ sPPg== X-Gm-Message-State: AOJu0YyLwOBdtdDtAnVyAfx0Fh9U9NpNwuOkPvDqJhQVCt+3IzUioW2X 4xR2sm8jmzumAUVo9daQmM4= X-Google-Smtp-Source: AGHT+IG23vHmmq5dt8Yji4Qi7S1XudTIkyWu+mxKHTirLdpb/eamQgSuYMZOb9/O24SwLcbnvoAZUA== X-Received: by 2002:a05:6a00:1142:b0:6be:23dd:d612 with SMTP id b2-20020a056a00114200b006be23ddd612mr13346578pfm.16.1698212522333; Tue, 24 Oct 2023 22:42:02 -0700 (PDT) Received: from surya ([2600:1700:3ec2:2011:3ef3:bbdb:b46b:4676]) by smtp.gmail.com with ESMTPSA id v189-20020a6261c6000000b006be0b0fc83asm8925549pfb.125.2023.10.24.22.42.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 24 Oct 2023 22:42:01 -0700 (PDT) Date: Tue, 24 Oct 2023 22:41:59 -0700 From: Manu Bretelle To: Kui-Feng Lee , ast@kernel.org Cc: bpf@vger.kernel.org, andrii@kernel.org, daniel@iogearbox.net, martin.lau@linux.dev, song@kernel.org, yonghong.song@linux.dev, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com, haoluo@google.com, jolsa@kernel.org, mykolal@fb.com, shuah@kernel.org Subject: Re: [PATCH bpf-next] selftests/bpf: umount children of TDIR in test_bpffs Message-ID: References: <20231024201852.1512720-1-chantr4@gmail.com> <041a3ea2-8cc6-4f0f-8ed9-6ca459e5bbb7@gmail.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <041a3ea2-8cc6-4f0f-8ed9-6ca459e5bbb7@gmail.com> On Tue, Oct 24, 2023 at 02:29:19PM -0700, Kui-Feng Lee wrote: > > > On 10/24/23 13:18, Manu Bretelle wrote: > > Currently this tests tries to umount /sys/kernel/debug (TDIR) but the > > system it is running on may have mounts below. > > > > For example, danobi/vmtest [0] VMs have > > mount -t tracefs tracefs /sys/kernel/debug/tracing > > as part of their init. > > > > This change list mounts and will umount any mounts below TDIR before > > umounting TDIR itself. > > > > Note that it is not umounting recursively, so in the case of a sub-mount > > of TDIR having another sub-mount, this will fail as mtab is ordered. > > Should we move TID to a random path likes "/sys/kernel/debug-/"? > Fair point, I suppose we would want to keep TDIR a defined string as it does simplify the gymnastic involved through the rest of the script, but yeah looking at the original commit: edb65ee5aa25 (selftests/bpf: Add bpffs preload test) I don't see any reason to use an alternate directory and rather mkdir it vs umounting the original one. so something like #define TDIR "/sys/kernel/test_bpffs" Would probably do. Alexei could confirm his original intent probably. > > > > Test: > > > > Originally: > > > > $ vmtest -k $KERNEL_REPO/arch/x86_64/boot/bzImage "./test_progs -vv -a test_bpffs" > > => bzImage > > ===> Booting > > ===> Setting up VM > > ===> Running command > > [ 2.138818] bpf_testmod: loading out-of-tree module taints kernel. > > [ 2.140913] bpf_testmod: module verification failed: signature and/or required key missing - tainting kernel > > bpf_testmod.ko is already unloaded. > > Loading bpf_testmod.ko... > > Successfully loaded bpf_testmod.ko. > > test_test_bpffs:PASS:clone 0 nsec > > fn:PASS:unshare 0 nsec > > fn:PASS:mount / 0 nsec > > fn:FAIL:umount /sys/kernel/debug unexpected error: -1 (errno 16) > > bpf_testmod.ko is already unloaded. > > Loading bpf_testmod.ko... > > Successfully loaded bpf_testmod.ko. > > test_test_bpffs:PASS:clone 0 nsec > > test_test_bpffs:PASS:waitpid 0 nsec > > test_test_bpffs:FAIL:bpffs test failed 255#282 test_bpffs:FAIL > > Summary: 0/0 PASSED, 0 SKIPPED, 1 FAILED > > Successfully unloaded bpf_testmod.ko. > > Command failed with exit code: 1 > > > > After this change: > > > > $ vmtest -k $KERNEL_REPO/arch/x86_64/boot/bzImage "./test_progs -vv -a test_bpffs" > > => bzImage > > ===> Booting > > ===> Setting up VM > > ===> Running command > > [ 2.035210] bpf_testmod: loading out-of-tree module taints kernel. > > [ 2.036510] bpf_testmod: module verification failed: signature and/or required key missing - tainting kernel > > bpf_testmod.ko is already unloaded. > > Loading bpf_testmod.ko... > > Successfully loaded bpf_testmod.ko. > > test_test_bpffs:PASS:clone 0 nsec > > fn:PASS:unshare 0 nsec > > fn:PASS:mount / 0 nsec > > fn:PASS:accessing /etc/mtab 0 nsec > > fn:PASS:umount /sys/kernel/debug/tracing 0 nsec > > fn:PASS:umount /sys/kernel/debug 0 nsec > > fn:PASS:mount tmpfs 0 nsec > > fn:PASS:mkdir /sys/kernel/debug/fs1 0 nsec > > fn:PASS:mkdir /sys/kernel/debug/fs2 0 nsec > > fn:PASS:mount bpffs /sys/kernel/debug/fs1 0 nsec > > fn:PASS:mount bpffs /sys/kernel/debug/fs2 0 nsec > > fn:PASS:reading /sys/kernel/debug/fs1/maps.debug 0 nsec > > fn:PASS:reading /sys/kernel/debug/fs2/progs.debug 0 nsec > > fn:PASS:creating /sys/kernel/debug/fs1/a 0 nsec > > fn:PASS:creating /sys/kernel/debug/fs1/a/1 0 nsec > > fn:PASS:creating /sys/kernel/debug/fs1/b 0 nsec > > fn:PASS:create_map(ARRAY) 0 nsec > > fn:PASS:pin map 0 nsec > > fn:PASS:stat(/sys/kernel/debug/fs1/a) 0 nsec > > fn:PASS:renameat2(/fs1/a, /fs1/b, RENAME_EXCHANGE) 0 nsec > > fn:PASS:stat(/sys/kernel/debug/fs1/b) 0 nsec > > fn:PASS:b should have a's inode 0 nsec > > fn:PASS:access(/sys/kernel/debug/fs1/b/1) 0 nsec > > fn:PASS:stat(/sys/kernel/debug/fs1/map) 0 nsec > > fn:PASS:renameat2(/fs1/c, /fs1/b, RENAME_EXCHANGE) 0 nsec > > fn:PASS:stat(/sys/kernel/debug/fs1/b) 0 nsec > > fn:PASS:b should have c's inode 0 nsec > > fn:PASS:access(/sys/kernel/debug/fs1/c/1) 0 nsec > > fn:PASS:renameat2(RENAME_NOREPLACE) 0 nsec > > fn:PASS:access(/sys/kernel/debug/fs1/b) 0 nsec > > bpf_testmod.ko is already unloaded. > > Loading bpf_testmod.ko... > > Successfully loaded bpf_testmod.ko. > > test_test_bpffs:PASS:clone 0 nsec > > test_test_bpffs:PASS:waitpid 0 nsec > > test_test_bpffs:PASS:bpffs test 0 nsec > > #282 test_bpffs:OK > > Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED > > Successfully unloaded bpf_testmod.ko. > > > > [0] https://github.com/danobi/vmtest > > > > Signed-off-by: Manu Bretelle > > --- > > .../selftests/bpf/prog_tests/test_bpffs.c | 28 +++++++++++++++++++ > > 1 file changed, 28 insertions(+) > > > > diff --git a/tools/testing/selftests/bpf/prog_tests/test_bpffs.c b/tools/testing/selftests/bpf/prog_tests/test_bpffs.c > > index 214d9f4a94a5..001bf694c269 100644 > > --- a/tools/testing/selftests/bpf/prog_tests/test_bpffs.c > > +++ b/tools/testing/selftests/bpf/prog_tests/test_bpffs.c > > @@ -3,12 +3,14 @@ > > #define _GNU_SOURCE > > #include > > #include > > +#include > > #include > > #include > > #include > > #include > > #define TDIR "/sys/kernel/debug" > > +#define MTAB "/etc/mtab" > > static int read_iter(char *file) > > { > > @@ -32,6 +34,8 @@ static int read_iter(char *file) > > static int fn(void) > > { > > + /* A buffer to store logging messages */ > > + char buf[1024]; > > struct stat a, b, c; > > int err, map; > > @@ -43,6 +47,30 @@ static int fn(void) > > if (!ASSERT_OK(err, "mount /")) > > goto out; > > + /* TDIR may have mounts below. unount them first */ > > + FILE *mtab = setmntent(MTAB, "r"); > > + > > + if (!ASSERT_TRUE(mtab != NULL, "accessing " MTAB)) { > > + err = errno; > > + goto out; > > + } > > + > > + struct mntent *mnt = NULL; > > + > > + while ((mnt = getmntent(mtab)) != NULL) { > > + if (strlen(mnt->mnt_dir) > strlen(TDIR) && > > + strncmp(TDIR, mnt->mnt_dir, strlen(TDIR)) == 0) { > > + snprintf(buf, sizeof(buf) - 1, "umount %s", mnt->mnt_dir); > > + err = umount(mnt->mnt_dir); > > + if (!ASSERT_OK(err, buf)) { > > + endmntent(mtab); > > + goto out; > > + } > > + } > > + } > > + // Ignore any error here > > + endmntent(mtab); > > + > > err = umount(TDIR); > > if (!ASSERT_OK(err, "umount " TDIR)) > > goto out;