From patchwork Sat May 11 17:14:39 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= X-Patchwork-Id: 13662440 Received: from smtp-8fae.mail.infomaniak.ch (smtp-8fae.mail.infomaniak.ch [83.166.143.174]) (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 ED5A61C6B7 for ; Sat, 11 May 2024 17:15:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=83.166.143.174 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715447706; cv=none; b=X1qVb2ZGeTYZdYU4kvIEl1rez+pSW0FYQHKn4hdNrOT8gFsmAfCu2vohrThgiFSgp/DzlCqNKmxVUQkLtKRKQ33Y1y4iF28m+BY2LcNmpcilBQ0ME7SJ707pmOBZeFYNVNia0MFTAfvnNEZ6DmE13yBFIiaeuyMS0zOy9noiBbg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715447706; c=relaxed/simple; bh=TSFlfFFKghB8eHp9D3n3uLja5CEBEmaChN7Prcn4c0c=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Tr9b7j7lBF2e+3nBUKhKHben+js/3LZQlAmQaJ76GM0QZsJP8h62mjyeB3JFK3R7vcexi1eSrs5cQkokbnWouA4yHwoGiBVDZCg27H7OTTPktQw56/5Mj2AFwj0OpbcXXe//F02YjmQ7awP8CvHbc6vaXtcX4PuSMZ/s+uxe0Kg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=digikod.net; spf=pass smtp.mailfrom=digikod.net; dkim=pass (1024-bit key) header.d=digikod.net header.i=@digikod.net header.b=eUCAN7j8; arc=none smtp.client-ip=83.166.143.174 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=digikod.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=digikod.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=digikod.net header.i=@digikod.net header.b="eUCAN7j8" Received: from smtp-4-0000.mail.infomaniak.ch (smtp-4-0000.mail.infomaniak.ch [10.7.10.107]) by smtp-3-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4VcC6m2wbKzdgn; Sat, 11 May 2024 19:14:56 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=digikod.net; s=20191114; t=1715447696; bh=8JJOgijbuR5/kAVTe97EDz4QytUjmeXuS/y3d7NXyAo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eUCAN7j8zU+baxpUtsZ9Q4G2ra4m/n3AHR2hCh0KeQCQl4ZHGubztDQyn9fI4xXht C6VHcgoGoK/D3wpAsITlrrQE6qd+QU1OLxlcMfA8IeAsNqB86kD/iM0D1MxdObrqIl ncFFk1DsAjh75AowKnBRpg1E7NN9Wuh029Bhq0Us= Received: from unknown by smtp-4-0000.mail.infomaniak.ch (Postfix) with ESMTPA id 4VcC6l5GvVzRh3; Sat, 11 May 2024 19:14:55 +0200 (CEST) From: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= To: Christian Brauner , Greg Kroah-Hartman , Jakub Kicinski , Kees Cook , Linus Torvalds , Mark Brown , Sasha Levin , Sean Christopherson , Shengyu Li , Shuah Khan , Shuah Khan Cc: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Bagas Sanjaya , Brendan Higgins , David Gow , "David S . Miller" , Florian Fainelli , =?utf-8?q?G=C3=BCnther_No?= =?utf-8?q?ack?= , Jon Hunter , Ron Economos , Ronald Warsow , Stephen Rothwell , Will Drewry , kernel test robot , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, netdev@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH v7 04/10] selftests/harness: Fix interleaved scheduling leading to race conditions Date: Sat, 11 May 2024 19:14:39 +0200 Message-ID: <20240511171445.904356-5-mic@digikod.net> In-Reply-To: <20240511171445.904356-1-mic@digikod.net> References: <20240511171445.904356-1-mic@digikod.net> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Infomaniak-Routing: alpha Fix a race condition when running several FIXTURE_TEARDOWN() managing the same resource. This fixes a race condition in the Landlock file system tests when creating or unmounting the same directory. Using clone3() with CLONE_VFORK guarantees that the child and grandchild test processes are sequentially scheduled. This is implemented with a new clone3_vfork() helper replacing the fork() call. This avoids triggering this error in __wait_for_test(): Test ended in some other way [127] Cc: Christian Brauner Cc: David S. Miller Cc: Günther Noack Cc: Jakub Kicinski Cc: Mark Brown Cc: Shuah Khan Cc: Will Drewry Fixes: 41cca0542d7c ("selftests/harness: Fix TEST_F()'s vfork handling") Reviewed-by: Kees Cook Signed-off-by: Mickaël Salaün Link: https://lore.kernel.org/r/20240511171445.904356-5-mic@digikod.net --- Changes since v2: * Replace __attribute__((__unused__)) with inline for clone3_vfork() (suggested by Kees and Jakub) --- tools/testing/selftests/kselftest_harness.h | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/kselftest_harness.h b/tools/testing/selftests/kselftest_harness.h index 55699a762c45..9d7178a71c2c 100644 --- a/tools/testing/selftests/kselftest_harness.h +++ b/tools/testing/selftests/kselftest_harness.h @@ -66,6 +66,8 @@ #include #include #include +#include +#include #include "kselftest.h" @@ -80,6 +82,17 @@ # define TH_LOG_ENABLED 1 #endif +/* Wait for the child process to end but without sharing memory mapping. */ +static inline pid_t clone3_vfork(void) +{ + struct clone_args args = { + .flags = CLONE_VFORK, + .exit_signal = SIGCHLD, + }; + + return syscall(__NR_clone3, &args, sizeof(args)); +} + /** * TH_LOG() * @@ -1183,7 +1196,7 @@ void __run_test(struct __fixture_metadata *f, fflush(stdout); fflush(stderr); - t->pid = fork(); + t->pid = clone3_vfork(); if (t->pid < 0) { ksft_print_msg("ERROR SPAWNING TEST CHILD\n"); t->exit_code = KSFT_FAIL;