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 7DAF91DFE00 for ; Thu, 20 Mar 2025 13:24:21 +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=1742477061; cv=none; b=gz3ib44q91SZYwDU2HmdmucLhoqKolLfS8TbwbqFZX4PDHZYvorVYOn3BRkGL14hzpUpJ3cXyc4fj0nb9bgJ9wnWADU8iuFfFw8dICLV1pkam65cFdv7evndSjGpfbTecb6bxmJF1j8Zv5hSBkA8xl15bi4Yn0M9XG4lPfkt4PA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742477061; c=relaxed/simple; bh=nbqWaPaXqyDnB0HDQ1wL/80R9Ma05kzOsoIHnfmrKKY=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=iQClOhYt8EPdCyVSafhwyDxdy9CYpczGAu4tXpKhRxbxf7w+af3FkalT1bDNcPbef+167O40uu2yMs/FTZVjoZch8NNz9Q/YpiQKADHxF8sdwy98pGdLxVDV30j7OBj/9qyVaEIT/u8PtLF3oMyNeWESOy2ZQ/FyjoJNbavsdEg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=f3MR5Ibh; 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="f3MR5Ibh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F00CDC4CEDD; Thu, 20 Mar 2025 13:24:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1742477061; bh=nbqWaPaXqyDnB0HDQ1wL/80R9Ma05kzOsoIHnfmrKKY=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=f3MR5Ibhd2l+kn1XAlXC9u4BxOCgL9hW/IoqJfqcKvrWbPIIOXsrUZAXif+lfzMML UCi919NexzlKHrEB7t95V/71lXEZGVLoaaPDbWhcNpjbhannJuYN7xCzAmQdq2s6mI OubaWPAuBGmTwqMYXKAmgHKxlmv0961JUGayCMK11BC/UY1tN6px2Ortpw2qGkuId9 3OR0Ui0qCVRAhCgWexPN2xmQEVPxyz4aFoI4RWWz58LAo4cksG7ImWivOmVf7+gjAd akI0lhEn3cuSzcC3EEWVeNFKnJhG1yNsx9RKDdob3le5S6LGZ5+WdweHq5MQeNYkNk OY8o2PzFq62yA== From: Christian Brauner Date: Thu, 20 Mar 2025 14:24:09 +0100 Subject: [PATCH v4 2/4] selftests/pidfd: first test for multi-threaded exec polling Precedence: bulk X-Mailing-List: linux-fsdevel@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: <20250320-work-pidfs-thread_group-v4-2-da678ce805bf@kernel.org> References: <20250320-work-pidfs-thread_group-v4-0-da678ce805bf@kernel.org> In-Reply-To: <20250320-work-pidfs-thread_group-v4-0-da678ce805bf@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=2472; i=brauner@kernel.org; h=from:subject:message-id; bh=nbqWaPaXqyDnB0HDQ1wL/80R9Ma05kzOsoIHnfmrKKY=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMaTfEfsnP/9yvGZfauZsZQuhA0Uy1k+/6HY1efx4KWvDx 13/r0O7o5SFQYyLQVZMkcWh3SRcbjlPxWajTA2YOaxMIEMYuDgFYCLHQxn+17KppTiVxkhtt97x 2OHJP8u3z/7d+/hS/ebBGAYd/w6rKYwMV5kEteLqpTMSQmo/Gq10zTfxm6E35cj+ns6AEp9H+3f xAgA= X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 Add first test for premature thread-group leader exit. Signed-off-by: Christian Brauner --- tools/testing/selftests/pidfd/pidfd_info_test.c | 38 ++++++++++++++++++++----- 1 file changed, 31 insertions(+), 7 deletions(-) diff --git a/tools/testing/selftests/pidfd/pidfd_info_test.c b/tools/testing/selftests/pidfd/pidfd_info_test.c index 09bc4ae7aed5..28a28ae4686a 100644 --- a/tools/testing/selftests/pidfd/pidfd_info_test.c +++ b/tools/testing/selftests/pidfd/pidfd_info_test.c @@ -236,7 +236,7 @@ static void *pidfd_info_pause_thread(void *arg) TEST_F(pidfd_info, thread_group) { - pid_t pid_leader, pid_thread; + pid_t pid_leader, pid_poller, pid_thread; pthread_t thread; int nevents, pidfd_leader, pidfd_thread, pidfd_leader_thread, ret; int ipc_sockets[2]; @@ -262,6 +262,35 @@ TEST_F(pidfd_info, thread_group) syscall(__NR_exit, EXIT_SUCCESS); } + /* + * 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); + + pid_poller = fork(); + ASSERT_GE(pid_poller, 0); + if (pid_poller == 0) { + /* + * We can't poll and wait for the old thread-group + * leader to exit using a thread-specific pidfd. The + * thread-group leader exited prematurely and + * notification is delayed until all subthreads have + * exited. + */ + fds.events = POLLIN; + fds.fd = pidfd_leader_thread; + nevents = poll(&fds, 1, 10000 /* wait 5 seconds */); + if (nevents != 0) + _exit(EXIT_FAILURE); + if (fds.revents & POLLIN) + _exit(EXIT_FAILURE); + if (fds.revents & POLLHUP) + _exit(EXIT_FAILURE); + _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)); @@ -275,12 +304,7 @@ TEST_F(pidfd_info, thread_group) 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); + ASSERT_EQ(wait_for_pid(pid_poller), 0); /* * Note that pidfd_leader is a thread-group pidfd, so polling on it -- 2.47.2