From patchwork Wed Mar 5 10:08:25 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 14002283 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 9B4562063EE for ; Wed, 5 Mar 2025 10:08:58 +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=1741169338; cv=none; b=ECm3wdmB8prCILgic2crZ5kPfMhUNnI7dWQ86OxTQXGR4ES6uYnE0JM8KhH9Wv1xzQsYnRaqFC8L324eOMEtYTg6mTOWTas0ZUcPpCgOkmt91rYaJB/HBOjK3VcwQ7oVayeCMe3UQnfhRXAfc322TLKYAPc4TimDJzaToFY/AJY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741169338; c=relaxed/simple; bh=n1AmvJGTE+dyEb9yOEMqfK/t0tSBbHA/ZFXA20F2ATU=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=UbRZOO6PLMrkXCFdAkw6j6VPtFr6IavIM0GqnoHiNFc0tVX3XzYZvLZo7RZi2OiwY08h3BKIVQf9NCkDGxR7rtN6nq+bDs7jGpIOCjGkQ3biFgdSYwse9vQsPxOX0yXcnksJeZK6TFyhh1aXyUa3e+rwzXgZou8HctQ2TudLb64= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=GAO6mqOu; 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="GAO6mqOu" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9354DC4CEE8; Wed, 5 Mar 2025 10:08:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1741169338; bh=n1AmvJGTE+dyEb9yOEMqfK/t0tSBbHA/ZFXA20F2ATU=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=GAO6mqOudhuBr0X7TUoV8q9nKy/A0crUZIXYAqwRa8y41v48IyYwIakLf62LaXz7g gqN1Rt33wwm1mjwo6LWKIZ7y5xgZRbppgLCCtyI8OfvbumkFq209vIv9pMidlL9enj 6jmUsEhPG84BH1ltW8Ln+4EyQOox25tsPFOGD5kiY1eZVhj2T2ZzHI5yHgZnWfc/Xb Ciov+yM3aD+GbOyIJZ7uqTgb4XxdMdH/PQbqKIvkR5NotGRWr1ilCNJs4aDkCW7mGG +p3/a07RU8MWcdqYEV4mKWeLBHicw7vmalve1i6t6KA/RG3UOp8OyZEvduUdLJrQt0 Mrol90+Bap+HQ== From: Christian Brauner Date: Wed, 05 Mar 2025 11:08:25 +0100 Subject: [PATCH v3 15/16] selftests/pidfd: add sixth PIDFD_INFO_EXIT selftest Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20250305-work-pidfs-kill_on_last_close-v3-15-c8c3d8361705@kernel.org> References: <20250305-work-pidfs-kill_on_last_close-v3-0-c8c3d8361705@kernel.org> In-Reply-To: <20250305-work-pidfs-kill_on_last_close-v3-0-c8c3d8361705@kernel.org> To: Oleg Nesterov Cc: linux-fsdevel@vger.kernel.org, Jeff Layton , Lennart Poettering , Daan De Meyer , Mike Yuan , Christian Brauner X-Mailer: b4 0.15-dev-42535 X-Developer-Signature: v=1; a=openpgp-sha256; l=6744; i=brauner@kernel.org; h=from:subject:message-id; bh=n1AmvJGTE+dyEb9yOEMqfK/t0tSBbHA/ZFXA20F2ATU=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMaSfUJphzuXmrXnT4mJ36KTVB9gtDog76PwO3cXrPTP6N GOB1fbDHaUsDGJcDLJiiiwO7Sbhcst5KjYbZWrAzGFlAhnCwMUpABOZaMjIMMtpSfX2OrftnWVS a/n/mpdYsLqeiFSo/dnarM9hk50ewMjQsCE9921h4B7L8Fl75sXEsh6fIRWzy9YmtShAbfKe+ay cAA== X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Add a selftest for PIDFD_INFO_EXIT behavior. Link: https://lore.kernel.org/r/20250304-work-pidfs-kill_on_last_close-v2-15-44fdacfaa7b7@kernel.org Signed-off-by: Christian Brauner --- tools/testing/selftests/pidfd/pidfd.h | 4 + tools/testing/selftests/pidfd/pidfd_info_test.c | 151 ++++++++++++++++++++++++ 2 files changed, 155 insertions(+) diff --git a/tools/testing/selftests/pidfd/pidfd.h b/tools/testing/selftests/pidfd/pidfd.h index cc8e381978df..fee6fd3e67dd 100644 --- a/tools/testing/selftests/pidfd/pidfd.h +++ b/tools/testing/selftests/pidfd/pidfd.h @@ -131,6 +131,10 @@ #define PIDFD_INFO_EXIT (1UL << 3) /* Always returned if available, even if not requested */ #endif +#ifndef PIDFD_THREAD +#define PIDFD_THREAD O_EXCL +#endif + struct pidfd_info { __u64 mask; __u64 cgroupid; diff --git a/tools/testing/selftests/pidfd/pidfd_info_test.c b/tools/testing/selftests/pidfd/pidfd_info_test.c index 16e4be2364df..5e86e3df323b 100644 --- a/tools/testing/selftests/pidfd/pidfd_info_test.c +++ b/tools/testing/selftests/pidfd/pidfd_info_test.c @@ -218,4 +218,155 @@ TEST_F(pidfd_info, success_reaped_poll) ASSERT_EQ(WTERMSIG(info.exit_code), SIGKILL); } +static void *pidfd_info_pause_thread(void *arg) +{ + pid_t pid_thread = gettid(); + int ipc_socket = *(int *)arg; + + /* Inform the grand-parent what the tid of this thread is. */ + if (write_nointr(ipc_socket, &pid_thread, sizeof(pid_thread)) != sizeof(pid_thread)) + return NULL; + + close(ipc_socket); + + /* Sleep untill we're killed. */ + pause(); + return NULL; +} + +TEST_F(pidfd_info, thread_group) +{ + pid_t pid_leader, pid_thread; + pthread_t thread; + int nevents, pidfd_leader, pidfd_thread, pidfd_leader_thread, ret; + int ipc_sockets[2]; + struct pollfd fds = {}; + struct pidfd_info info = { + .mask = PIDFD_INFO_CGROUPID | PIDFD_INFO_EXIT, + }, info2; + + ret = socketpair(AF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0, ipc_sockets); + EXPECT_EQ(ret, 0); + + pid_leader = create_child(&pidfd_leader, 0); + EXPECT_GE(pid_leader, 0); + + if (pid_leader == 0) { + close(ipc_sockets[0]); + + /* The thread will outlive the thread-group leader. */ + if (pthread_create(&thread, NULL, pidfd_info_pause_thread, &ipc_sockets[1])) + syscall(__NR_exit, EXIT_FAILURE); + + /* Make the thread-group leader exit prematurely. */ + syscall(__NR_exit, EXIT_SUCCESS); + } + + /* Retrieve the tid of the thread. */ + EXPECT_EQ(close(ipc_sockets[1]), 0); + ASSERT_EQ(read_nointr(ipc_sockets[0], &pid_thread, sizeof(pid_thread)), sizeof(pid_thread)); + EXPECT_EQ(close(ipc_sockets[0]), 0); + + /* Opening a thread as a thread-group leader must fail. */ + pidfd_thread = sys_pidfd_open(pid_thread, 0); + ASSERT_LT(pidfd_thread, 0); + + /* Opening a thread as a PIDFD_THREAD must succeed. */ + pidfd_thread = sys_pidfd_open(pid_thread, PIDFD_THREAD); + ASSERT_GE(pidfd_thread, 0); + + /* + * Opening a PIDFD_THREAD aka thread-specific pidfd based on a + * thread-group leader must succeed. + */ + pidfd_leader_thread = sys_pidfd_open(pid_leader, PIDFD_THREAD); + ASSERT_GE(pidfd_leader_thread, 0); + + /* + * Note that pidfd_leader is a thread-group pidfd, so polling on it + * would only notify us once all thread in the thread-group have + * exited. So we can't poll before we have taken down the whole + * thread-group. + */ + + /* Get PIDFD_GET_INFO using the thread-group leader pidfd. */ + ASSERT_EQ(ioctl(pidfd_leader, PIDFD_GET_INFO, &info), 0); + ASSERT_TRUE(!!(info.mask & PIDFD_INFO_CREDS)); + /* Process has exited but not been reaped, so no PIDFD_INFO_EXIT information yet. */ + ASSERT_FALSE(!!(info.mask & PIDFD_INFO_EXIT)); + ASSERT_EQ(info.pid, pid_leader); + + /* + * Now retrieve the same info using the thread specific pidfd + * for the thread-group leader. + */ + info2.mask = PIDFD_INFO_CGROUPID | PIDFD_INFO_EXIT; + ASSERT_EQ(ioctl(pidfd_leader_thread, PIDFD_GET_INFO, &info2), 0); + ASSERT_TRUE(!!(info2.mask & PIDFD_INFO_CREDS)); + /* Process has exited but not been reaped, so no PIDFD_INFO_EXIT information yet. */ + ASSERT_FALSE(!!(info2.mask & PIDFD_INFO_EXIT)); + ASSERT_EQ(info2.pid, pid_leader); + + /* Now try the thread-specific pidfd. */ + ASSERT_EQ(ioctl(pidfd_thread, PIDFD_GET_INFO, &info), 0); + ASSERT_TRUE(!!(info.mask & PIDFD_INFO_CREDS)); + /* The thread hasn't exited, so no PIDFD_INFO_EXIT information yet. */ + ASSERT_FALSE(!!(info.mask & PIDFD_INFO_EXIT)); + ASSERT_EQ(info.pid, pid_thread); + + /* + * Take down the whole thread-group. The thread-group leader + * exited successfully but the thread will now be SIGKILLed. + * This must be reflected in the recorded exit information. + */ + EXPECT_EQ(sys_pidfd_send_signal(pidfd_leader, SIGKILL, NULL, 0), 0); + EXPECT_EQ(sys_waitid(P_PIDFD, pidfd_leader, NULL, WEXITED), 0); + + fds.events = POLLIN; + fds.fd = pidfd_leader; + nevents = poll(&fds, 1, -1); + ASSERT_EQ(nevents, 1); + ASSERT_TRUE(!!(fds.revents & POLLIN)); + /* The thread-group leader has been reaped. */ + ASSERT_TRUE(!!(fds.revents & POLLHUP)); + + /* + * Retrieve exit information for the thread-group leader via the + * thread-group leader pidfd. + */ + info.mask = PIDFD_INFO_CGROUPID | PIDFD_INFO_EXIT; + ASSERT_EQ(ioctl(pidfd_leader, PIDFD_GET_INFO, &info), 0); + ASSERT_FALSE(!!(info.mask & PIDFD_INFO_CREDS)); + ASSERT_TRUE(!!(info.mask & PIDFD_INFO_EXIT)); + /* The thread-group leader exited successfully. Only the specific thread was SIGKILLed. */ + ASSERT_TRUE(WIFEXITED(info.exit_code)); + ASSERT_EQ(WEXITSTATUS(info.exit_code), 0); + + /* + * Retrieve exit information for the thread-group leader via the + * thread-specific pidfd. + */ + info2.mask = PIDFD_INFO_CGROUPID | PIDFD_INFO_EXIT; + ASSERT_EQ(ioctl(pidfd_leader_thread, PIDFD_GET_INFO, &info2), 0); + ASSERT_FALSE(!!(info2.mask & PIDFD_INFO_CREDS)); + ASSERT_TRUE(!!(info2.mask & PIDFD_INFO_EXIT)); + + /* The thread-group leader exited successfully. Only the specific thread was SIGKILLed. */ + ASSERT_TRUE(WIFEXITED(info2.exit_code)); + ASSERT_EQ(WEXITSTATUS(info2.exit_code), 0); + + /* Retrieve exit information for the thread. */ + info.mask = PIDFD_INFO_CGROUPID | PIDFD_INFO_EXIT; + ASSERT_EQ(ioctl(pidfd_thread, PIDFD_GET_INFO, &info), 0); + ASSERT_FALSE(!!(info.mask & PIDFD_INFO_CREDS)); + ASSERT_TRUE(!!(info.mask & PIDFD_INFO_EXIT)); + + /* The thread got SIGKILLed. */ + ASSERT_TRUE(WIFSIGNALED(info.exit_code)); + ASSERT_EQ(WTERMSIG(info.exit_code), SIGKILL); + + EXPECT_EQ(close(pidfd_leader), 0); + EXPECT_EQ(close(pidfd_thread), 0); +} + TEST_HARNESS_MAIN