From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 427383148A6; Fri, 24 Oct 2025 10:54:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761303299; cv=none; b=ZyH1eA6xLHDy9VUOgR5EUwtOYUsi/CtaVt2CRG+JApjjaShhDTRlSQGO1t522GUmw8y6E7Ry7OYdvmbLRM0+6OFa49dmtZ9QaZifnc0nCrDi4OFqUSXFL8/ERSDtzHE+9lPodGPv/bGLXY0szliXgFpuGci44wLItiabfipZ220= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761303299; c=relaxed/simple; bh=aUj6NRVDEfXAvY88G+wOpYmY1IAUvRXs+4FwCz1W+QY=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=lZPaN0brtEMBfonWz9L/wYB+Dtp9/Fm4JQFvxdtJFgzEQY1Ce7fsJQ080S+nnNwFw52T/Xm3wc3fq0JNDHXetYQgVR0Xj3kyl1f4nl62qRs8JbQsOZtexfhOyA+FREBgLelZSr2dkyPKGf3E5mG1An9pUDcv0mYv+CgL7Un3RQw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=qez5EiCU; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="qez5EiCU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 34F2CC4CEF5; Fri, 24 Oct 2025 10:54:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1761303297; bh=aUj6NRVDEfXAvY88G+wOpYmY1IAUvRXs+4FwCz1W+QY=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=qez5EiCUWkoRmLtGfJCc1hhoQu6p/kggIz7DbRZ7B1skDkxjXJ2GnJajucNG5kLHu m/ZWGPInBW4PqnhbctuZr/rStVgbjmQGC/g6yo4Lax3EhEbXmaAk6UeO5QlNrlcQUZ DZEh8DqF7r5wPdbuB+c99+tkBv3eedeHSx6TgZYlvZFmBjRdDjpWyevhYZDFwcVr/X cXp5aZ67WVQbOFknoVsPrpiVqbSoAdNo3x2lTeIi4dHdBJGML59JIgo/S3RMT+1DAI b5NrJOlin1MC1E87Qjsi9KMt/6QLFnn0MKdnzSyq1n3T97qkLhi0xqql2q4fvLO0NR ZtaeTYVQHkcCA== From: Christian Brauner Date: Fri, 24 Oct 2025 12:52:52 +0200 Subject: [PATCH v3 23/70] selftests/namespaces: third active reference count tests Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20251024-work-namespace-nstree-listns-v3-23-b6241981b72b@kernel.org> References: <20251024-work-namespace-nstree-listns-v3-0-b6241981b72b@kernel.org> In-Reply-To: <20251024-work-namespace-nstree-listns-v3-0-b6241981b72b@kernel.org> To: linux-fsdevel@vger.kernel.org, Josef Bacik , Jeff Layton Cc: Jann Horn , Mike Yuan , =?utf-8?q?Zbigniew_J=C4=99drzejewski-Szmek?= , Lennart Poettering , Daan De Meyer , Aleksa Sarai , Amir Goldstein , Tejun Heo , Johannes Weiner , Thomas Gleixner , Alexander Viro , Jan Kara , linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, bpf@vger.kernel.org, Eric Dumazet , Jakub Kicinski , netdev@vger.kernel.org, Arnd Bergmann , Christian Brauner X-Mailer: b4 0.15-dev-96507 X-Developer-Signature: v=1; a=openpgp-sha256; l=3551; i=brauner@kernel.org; h=from:subject:message-id; bh=aUj6NRVDEfXAvY88G+wOpYmY1IAUvRXs+4FwCz1W+QY=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMWT8jmo1Djq61+b6tt3c33knTAtvfbClfdWBP+KJludiL uy88z8nqaOUhUGMi0FWTJHFod0kXG45T8Vmo0wNmDmsTCBDGLg4BWAiD/cz/GR0nL1mr7qLpC27 fPCM0FvhK+6Euq9zv9u3799fZ4GmZnlGhtayWTE5Z6++nruB8dXFtL7PUzh+XC9YkDKvWXCRxzf XLnYA X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Test that a namespace remains active while a process is using it, even after the creating process exits. Signed-off-by: Christian Brauner --- .../selftests/namespaces/ns_active_ref_test.c | 124 +++++++++++++++++++++ 1 file changed, 124 insertions(+) diff --git a/tools/testing/selftests/namespaces/ns_active_ref_test.c b/tools/testing/selftests/namespaces/ns_active_ref_test.c index 7cade298c754..c2e34de7a3a9 100644 --- a/tools/testing/selftests/namespaces/ns_active_ref_test.c +++ b/tools/testing/selftests/namespaces/ns_active_ref_test.c @@ -152,4 +152,128 @@ TEST(ns_inactive_after_exit) ASSERT_TRUE(errno == ENOENT || errno == ESTALE); } +/* + * Test that a namespace remains active while a process is using it, + * even after the creating process exits. + */ +TEST(ns_active_with_multiple_processes) +{ + struct file_handle *handle; + int mount_id; + int ret; + int fd; + int pipefd[2]; + int syncpipe[2]; + pid_t pid1, pid2; + int status; + char buf[sizeof(*handle) + MAX_HANDLE_SZ]; + char sync_byte; + + /* Create pipes for communication */ + ASSERT_EQ(pipe(pipefd), 0); + ASSERT_EQ(pipe(syncpipe), 0); + + pid1 = fork(); + ASSERT_GE(pid1, 0); + + if (pid1 == 0) { + /* First child - creates namespace */ + close(pipefd[0]); + close(syncpipe[1]); + + /* Create new network namespace */ + ret = unshare(CLONE_NEWNET); + if (ret < 0) { + close(pipefd[1]); + close(syncpipe[0]); + exit(1); + } + + /* Open and get handle */ + fd = open("/proc/self/ns/net", O_RDONLY); + if (fd < 0) { + close(pipefd[1]); + close(syncpipe[0]); + exit(1); + } + + handle = (struct file_handle *)buf; + handle->handle_bytes = MAX_HANDLE_SZ; + ret = name_to_handle_at(fd, "", handle, &mount_id, AT_EMPTY_PATH); + close(fd); + + if (ret < 0) { + close(pipefd[1]); + close(syncpipe[0]); + exit(1); + } + + /* Send handle to parent */ + write(pipefd[1], buf, sizeof(*handle) + handle->handle_bytes); + close(pipefd[1]); + + /* Wait for signal before exiting */ + read(syncpipe[0], &sync_byte, 1); + close(syncpipe[0]); + exit(0); + } + + /* Parent reads handle */ + close(pipefd[1]); + ret = read(pipefd[0], buf, sizeof(buf)); + close(pipefd[0]); + ASSERT_GT(ret, 0); + + handle = (struct file_handle *)buf; + + /* Create second child that will keep namespace active */ + pid2 = fork(); + ASSERT_GE(pid2, 0); + + if (pid2 == 0) { + /* Second child - reopens the namespace */ + close(syncpipe[0]); + close(syncpipe[1]); + + /* Open the namespace via handle */ + fd = open_by_handle_at(FD_NSFS_ROOT, handle, O_RDONLY); + if (fd < 0) { + exit(1); + } + + /* Join the namespace */ + ret = setns(fd, CLONE_NEWNET); + close(fd); + if (ret < 0) { + exit(1); + } + + /* Sleep to keep namespace active */ + sleep(1); + exit(0); + } + + /* Let second child enter the namespace */ + usleep(100000); /* 100ms */ + + /* Signal first child to exit */ + close(syncpipe[0]); + sync_byte = 'X'; + write(syncpipe[1], &sync_byte, 1); + close(syncpipe[1]); + + /* Wait for first child */ + waitpid(pid1, &status, 0); + ASSERT_TRUE(WIFEXITED(status)); + + /* Namespace should still be active because second child is using it */ + fd = open_by_handle_at(FD_NSFS_ROOT, handle, O_RDONLY); + ASSERT_GE(fd, 0); + close(fd); + + /* Wait for second child */ + waitpid(pid2, &status, 0); + ASSERT_TRUE(WIFEXITED(status)); +} + TEST_HARNESS_MAIN -- 2.47.3