From patchwork Tue Mar 4 20:18:49 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Brauner X-Patchwork-Id: 14001356 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 8A2B02E3377 for ; Tue, 4 Mar 2025 20:19:08 +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=1741119548; cv=none; b=VzU76VZ+WP5SZ1yDoGaMy9/Cu++8gNzZKocy/apGHMDtdMehzF7/dp1tlgBIjGHFYEQh5gqeRxRCMEQ0IScZUxvzy3v5/QPc+rnsRpgzkYoRdvCI7qzkYMndI8p7u8O+Ayequ0h9w59esEWAaWqeVgnMnBEYE/KurFC3xwYxdz8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741119548; c=relaxed/simple; bh=VJcYo/O1WWxGodiRQPXRxCWmdrBiYbVH3cZrz9umSrw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NZit4ud3xnocj6J0r16tHWVJyGSvuZdyUo2QaktVsltJeJzvHVyiigsQ6b8fhCF/LSNPGJaHXUJzG+LR1cMKV2/E12aRMf/bFuUeBGZUWePwYvdLJXpuZgswkdL4jCoek2mC6XSWyEBkSZbBDQkAJ7ZOfo70TUYKKuYrpQHc+fk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=L0QcAk1Q; 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="L0QcAk1Q" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 31271C4CEE5; Tue, 4 Mar 2025 20:19:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1741119548; bh=VJcYo/O1WWxGodiRQPXRxCWmdrBiYbVH3cZrz9umSrw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=L0QcAk1Q6/HFnxEemwS3GFE98MvwxtKxlHRJ53HI7E/UpEDSFLUqt/xiRTfV4y414 I7dE4x7MdMWc0SV11EwlhkxeY1jTq4u98HrUHmQ9sIqyVQWZywWpyzG+9JNHaVoLiM +bMY103MCUBPQfvwUcVU6Lw5rpZoqj0a1PnICfzWuRMi9NBJmiG+uFtT29qZcdWLs/ fMB5+yiDwhs1bV6fbddOkd0KQ+Vkxjg55Z0itz3w2RdnhU1Ws3g72P6vycAcMu2jsx ftUyCaQTGjJTHnNpxxZT6okTlkUCTgAU85Wd1ayOtntq7T4glFm5zX1b4a3WHnvKLq k/NB9h6zvaYEQ== From: Christian Brauner To: Oleg Nesterov Cc: Christian Brauner , linux-fsdevel@vger.kernel.org, Jeff Layton , Lennart Poettering , Daan De Meyer , Mike Yuan Subject: [PATCH v2 17/16] selftests/pidfd: test multi-threaded exec with PPIDFD_INFO_EXIT Date: Tue, 4 Mar 2025 21:18:49 +0100 Message-ID: <20250304-paarweise-erlesen-be86ad628af7@brauner> X-Mailer: git-send-email 2.47.2 In-Reply-To: <20250304-work-pidfs-kill_on_last_close-v2-15-44fdacfaa7b7@kernel.org> References: <20250304-work-pidfs-kill_on_last_close-v2-15-44fdacfaa7b7@kernel.org> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=6352; i=brauner@kernel.org; h=from:subject:message-id; bh=VJcYo/O1WWxGodiRQPXRxCWmdrBiYbVH3cZrz9umSrw=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMaQfT9DZc43pDePulRsPTz8Z+oO1eKW3T66np3DBr5UC7 x6djigz6ShlYRDjYpAVU2RxaDcJl1vOU7HZKFMDZg4rE8gQBi5OAZjIfG1Ghv4XV9Jev2uxXX9n MZe++joeNQtLV5YYuWanti6ttC9a9gx/ZYznuV6ofbvzbY9f4I/+XS9Nf3wrnj1x9XQfZZXzi9s XMQMA X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Add a selftest for PIDFD_INFO_EXIT behavior. Signed-off-by: Christian Brauner --- tools/testing/selftests/pidfd/.gitignore | 1 + tools/testing/selftests/pidfd/Makefile | 2 + tools/testing/selftests/pidfd/pidfd.h | 7 ++ .../selftests/pidfd/pidfd_exec_helper.c | 12 +++ .../testing/selftests/pidfd/pidfd_info_test.c | 102 ++++++++++++++++++ 5 files changed, 124 insertions(+) create mode 100644 tools/testing/selftests/pidfd/pidfd_exec_helper.c diff --git a/tools/testing/selftests/pidfd/.gitignore b/tools/testing/selftests/pidfd/.gitignore index bddae1d4d7e4..0406a065deb4 100644 --- a/tools/testing/selftests/pidfd/.gitignore +++ b/tools/testing/selftests/pidfd/.gitignore @@ -9,3 +9,4 @@ pidfd_setns_test pidfd_file_handle_test pidfd_bind_mount pidfd_info_test +pidfd_exec_helper diff --git a/tools/testing/selftests/pidfd/Makefile b/tools/testing/selftests/pidfd/Makefile index a94c2bc8d594..fcbefc0d77f6 100644 --- a/tools/testing/selftests/pidfd/Makefile +++ b/tools/testing/selftests/pidfd/Makefile @@ -5,5 +5,7 @@ TEST_GEN_PROGS := pidfd_test pidfd_fdinfo_test pidfd_open_test \ pidfd_poll_test pidfd_wait pidfd_getfd_test pidfd_setns_test \ pidfd_file_handle_test pidfd_bind_mount pidfd_info_test +TEST_GEN_PROGS_EXTENDED := pidfd_exec_helper + include ../lib.mk diff --git a/tools/testing/selftests/pidfd/pidfd.h b/tools/testing/selftests/pidfd/pidfd.h index fee6fd3e67dd..cec22aa11cdf 100644 --- a/tools/testing/selftests/pidfd/pidfd.h +++ b/tools/testing/selftests/pidfd/pidfd.h @@ -254,4 +254,11 @@ static inline ssize_t write_nointr(int fd, const void *buf, size_t count) return ret; } +static inline int sys_execveat(int dirfd, const char *pathname, + char *const argv[], char *const envp[], + int flags) +{ + return syscall(__NR_execveat, dirfd, pathname, argv, envp, flags); +} + #endif /* __PIDFD_H */ diff --git a/tools/testing/selftests/pidfd/pidfd_exec_helper.c b/tools/testing/selftests/pidfd/pidfd_exec_helper.c new file mode 100644 index 000000000000..5516808c95f2 --- /dev/null +++ b/tools/testing/selftests/pidfd/pidfd_exec_helper.c @@ -0,0 +1,12 @@ +#define _GNU_SOURCE +#include +#include +#include + +int main(int argc, char *argv[]) +{ + if (pause()) + _exit(EXIT_FAILURE); + + _exit(EXIT_SUCCESS); +} diff --git a/tools/testing/selftests/pidfd/pidfd_info_test.c b/tools/testing/selftests/pidfd/pidfd_info_test.c index 5e86e3df323b..f159a6705a07 100644 --- a/tools/testing/selftests/pidfd/pidfd_info_test.c +++ b/tools/testing/selftests/pidfd/pidfd_info_test.c @@ -369,4 +369,106 @@ TEST_F(pidfd_info, thread_group) EXPECT_EQ(close(pidfd_thread), 0); } +static void *pidfd_info_thread_exec(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; + + if (read_nointr(ipc_socket, &pid_thread, sizeof(pid_thread)) != sizeof(pid_thread)) + return NULL; + + close(ipc_socket); + + sys_execveat(AT_FDCWD, "pidfd_exec_helper", NULL, NULL, 0); + return NULL; +} + +TEST_F(pidfd_info, thread_group_exec) +{ + pid_t pid_leader, pid_thread; + pthread_t thread; + int nevents, pidfd_leader, pidfd_thread, ret; + int ipc_sockets[2]; + struct pollfd fds = {}; + struct pidfd_info info = { + .mask = PIDFD_INFO_CGROUPID | PIDFD_INFO_EXIT, + }; + + 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_thread_exec, &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)); + + /* Opening a thread as a PIDFD_THREAD must succeed. */ + pidfd_thread = sys_pidfd_open(pid_thread, PIDFD_THREAD); + ASSERT_GE(pidfd_thread, 0); + + /* Now that we've opened a thread-specific pidfd the thread can exec. */ + ASSERT_EQ(write_nointr(ipc_sockets[0], &pid_thread, sizeof(pid_thread)), sizeof(pid_thread)); + EXPECT_EQ(close(ipc_sockets[0]), 0); + + /* Wait until the kernel has SIGKILLed the thread. */ + fds.events = POLLHUP; + fds.fd = pidfd_thread; + nevents = poll(&fds, 1, -1); + ASSERT_EQ(nevents, 1); + /* The thread has been reaped. */ + ASSERT_TRUE(!!(fds.revents & POLLHUP)); + + /* Retrieve thread-specific exit info from pidfd. */ + ASSERT_EQ(ioctl(pidfd_thread, PIDFD_GET_INFO, &info), 0); + ASSERT_FALSE(!!(info.mask & PIDFD_INFO_CREDS)); + ASSERT_TRUE(!!(info.mask & PIDFD_INFO_EXIT)); + /* + * While the kernel will have SIGKILLed the whole thread-group + * during exec it will cause the individual threads to exit + * cleanly. + */ + ASSERT_TRUE(WIFEXITED(info.exit_code)); + ASSERT_EQ(WEXITSTATUS(info.exit_code), 0); + + /* + * The thread-group leader is still alive, the thread has taken + * over its struct pid and thus its pid number. + */ + info.mask = PIDFD_INFO_CGROUPID | PIDFD_INFO_EXIT; + ASSERT_EQ(ioctl(pidfd_leader, PIDFD_GET_INFO, &info), 0); + ASSERT_TRUE(!!(info.mask & PIDFD_INFO_CREDS)); + ASSERT_FALSE(!!(info.mask & PIDFD_INFO_EXIT)); + ASSERT_EQ(info.pid, pid_leader); + + /* Take down the thread-group leader. */ + EXPECT_EQ(sys_pidfd_send_signal(pidfd_leader, SIGKILL, NULL, 0), 0); + EXPECT_EQ(sys_waitid(P_PIDFD, pidfd_leader, NULL, WEXITED), 0); + + /* Retrieve exit information for the thread-group leader. */ + 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)); + + EXPECT_EQ(close(pidfd_leader), 0); + EXPECT_EQ(close(pidfd_thread), 0); +} + TEST_HARNESS_MAIN