From patchwork Tue Mar 26 09:51:15 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: 13603793 Received: from smtp-1909.mail.infomaniak.ch (smtp-1909.mail.infomaniak.ch [185.125.25.9]) (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 389986FE39 for ; Tue, 26 Mar 2024 09:51:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.125.25.9 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711446711; cv=none; b=l2xSTGNCbjK1VtCF7n0JcZB47ZKb7QJJQymh6YrA2SWChMzDXg/booXkyhYcIxSYIpnh4y8HBLCJzUcBnvPGy9TSGXslmovuj0h1RZom67Zx699FbGcSm41FlQ9rP5xRugx5jYfamQCN5BYqwxMc0GQzvpM/GihP8draVvmEzMg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711446711; c=relaxed/simple; bh=raYOg3FDLnYzxat4KKO/e8ZSHhTV3Va2ltF0PaZ1ar0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Vmjh3woGM/5BGP9ROqOwfJzCkC0HQKMVyiAi4M5IyhYeF5aKcYzfX/ZPgizkivcIiTYC3DIy72ldlLff/W+0bRDWBYNMkj4hvofjFmRWgPwIkLZKEHlACRLePdGvC2PiEoKcHoGoYAlsSUHSIkV8FwcPT/eexD23i5wg/eVtPKE= 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=iQE1kpa3; arc=none smtp.client-ip=185.125.25.9 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="iQE1kpa3" Received: from smtp-3-0000.mail.infomaniak.ch (smtp-3-0000.mail.infomaniak.ch [10.4.36.107]) by smtp-4-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 4V3lSW5Mc6zcnF; Tue, 26 Mar 2024 10:51:39 +0100 (CET) Received: from unknown by smtp-3-0000.mail.infomaniak.ch (Postfix) with ESMTPA id 4V3lSV6N5vzr1; Tue, 26 Mar 2024 10:51:38 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=digikod.net; s=20191114; t=1711446699; bh=raYOg3FDLnYzxat4KKO/e8ZSHhTV3Va2ltF0PaZ1ar0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iQE1kpa3csr5WjCdjfgjU8KHXLpd7PQLFbpI3jqRlK3c4BiB3NmoXBk4Trc2n5SJ+ MUhh7m73G9Gffzc0BAe5eplq4HaMWGrWOQEOXhyXCSPwyEAVQZK8QUcPLMPs0ld8fm Oie0+3ZzjWBFJuNedg4mFN2yD2GU64ENdhCWvWz0= From: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= To: Brendan Higgins , David Gow , Rae Moar , Shuah Khan Cc: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Alan Maguire , Borislav Petkov , Dave Hansen , "Eric W . Biederman" , "H . Peter Anvin" , Ingo Molnar , James Morris , Kees Cook , Luis Chamberlain , "Madhavan T . Venkataraman" , Marco Pagani , Paolo Bonzini , Sean Christopherson , Stephen Boyd , Thara Gopinath , Thomas Gleixner , Vitaly Kuznetsov , Zahra Tarkhani , kvm@vger.kernel.org, linux-hardening@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, linux-um@lists.infradead.org, x86@kernel.org Subject: [PATCH v4 4/7] kunit: Handle test faults Date: Tue, 26 Mar 2024 10:51:15 +0100 Message-ID: <20240326095118.126696-5-mic@digikod.net> In-Reply-To: <20240326095118.126696-1-mic@digikod.net> References: <20240326095118.126696-1-mic@digikod.net> Precedence: bulk X-Mailing-List: linux-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Infomaniak-Routing: alpha Previously, when a kernel test thread crashed (e.g. NULL pointer dereference, general protection fault), the KUnit test hanged for 30 seconds and exited with a timeout error. Fix this issue by waiting on task_struct->vfork_done instead of the custom kunit_try_catch.try_completion, and track the execution state by initially setting try_result with -EINTR and only setting it to 0 if the test passed. Fix kunit_generic_run_threadfn_adapter() signature by returning 0 instead of calling kthread_complete_and_exit(). Because thread's exit code is never checked, always set it to 0 to make it clear. To make this explicit, export kthread_exit() for KUnit tests built as module. Fix the -EINTR error message, which couldn't be reached until now. This is tested with a following patch. Cc: Brendan Higgins Cc: Eric W. Biederman Cc: Shuah Khan Reviewed-by: Kees Cook Reviewed-by: David Gow Tested-by: Rae Moar Signed-off-by: Mickaël Salaün Link: https://lore.kernel.org/r/20240326095118.126696-5-mic@digikod.net --- Changes since v3: * Export kthread_exit() for KUnit tests built as module, as suggested by David. Changes since v2: * s/-EFAULT/-EINTR/ in commit message as spotted by Rae. * Add a comment explaining vfork_done as suggested by David. * Add David's Reviewed-by. * Add Rae's Tested-by. Changes since v1: * Add Kees's Reviewed-by. --- include/kunit/try-catch.h | 3 --- kernel/kthread.c | 1 + lib/kunit/try-catch.c | 19 ++++++++++++------- 3 files changed, 13 insertions(+), 10 deletions(-) diff --git a/include/kunit/try-catch.h b/include/kunit/try-catch.h index c507dd43119d..7c966a1adbd3 100644 --- a/include/kunit/try-catch.h +++ b/include/kunit/try-catch.h @@ -14,13 +14,11 @@ typedef void (*kunit_try_catch_func_t)(void *); -struct completion; struct kunit; /** * struct kunit_try_catch - provides a generic way to run code which might fail. * @test: The test case that is currently being executed. - * @try_completion: Completion that the control thread waits on while test runs. * @try_result: Contains any errno obtained while running test case. * @try: The function, the test case, to attempt to run. * @catch: The function called if @try bails out. @@ -46,7 +44,6 @@ struct kunit; struct kunit_try_catch { /* private: internal use only. */ struct kunit *test; - struct completion *try_completion; int try_result; kunit_try_catch_func_t try; kunit_try_catch_func_t catch; diff --git a/kernel/kthread.c b/kernel/kthread.c index c5e40830c1f2..f7be976ff88a 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -315,6 +315,7 @@ void __noreturn kthread_exit(long result) kthread->result = result; do_exit(0); } +EXPORT_SYMBOL(kthread_exit); /** * kthread_complete_and_exit - Exit the current kthread. diff --git a/lib/kunit/try-catch.c b/lib/kunit/try-catch.c index cab8b24b5d5a..7a3910dd78a6 100644 --- a/lib/kunit/try-catch.c +++ b/lib/kunit/try-catch.c @@ -18,7 +18,7 @@ void __noreturn kunit_try_catch_throw(struct kunit_try_catch *try_catch) { try_catch->try_result = -EFAULT; - kthread_complete_and_exit(try_catch->try_completion, -EFAULT); + kthread_exit(0); } EXPORT_SYMBOL_GPL(kunit_try_catch_throw); @@ -26,9 +26,12 @@ static int kunit_generic_run_threadfn_adapter(void *data) { struct kunit_try_catch *try_catch = data; + try_catch->try_result = -EINTR; try_catch->try(try_catch->context); + if (try_catch->try_result == -EINTR) + try_catch->try_result = 0; - kthread_complete_and_exit(try_catch->try_completion, 0); + return 0; } static unsigned long kunit_test_timeout(void) @@ -58,13 +61,11 @@ static unsigned long kunit_test_timeout(void) void kunit_try_catch_run(struct kunit_try_catch *try_catch, void *context) { - DECLARE_COMPLETION_ONSTACK(try_completion); struct kunit *test = try_catch->test; struct task_struct *task_struct; int exit_code, time_remaining; try_catch->context = context; - try_catch->try_completion = &try_completion; try_catch->try_result = 0; task_struct = kthread_create(kunit_generic_run_threadfn_adapter, try_catch, "kunit_try_catch_thread"); @@ -75,8 +76,12 @@ void kunit_try_catch_run(struct kunit_try_catch *try_catch, void *context) } get_task_struct(task_struct); wake_up_process(task_struct); - - time_remaining = wait_for_completion_timeout(&try_completion, + /* + * As for a vfork(2), task_struct->vfork_done (pointing to the + * underlying kthread->exited) can be used to wait for the end of a + * kernel thread. + */ + time_remaining = wait_for_completion_timeout(task_struct->vfork_done, kunit_test_timeout()); if (time_remaining == 0) { try_catch->try_result = -ETIMEDOUT; @@ -92,7 +97,7 @@ void kunit_try_catch_run(struct kunit_try_catch *try_catch, void *context) if (exit_code == -EFAULT) try_catch->try_result = 0; else if (exit_code == -EINTR) - kunit_err(test, "wake_up_process() was never called\n"); + kunit_err(test, "try faulted\n"); else if (exit_code == -ETIMEDOUT) kunit_err(test, "try timed out\n"); else if (exit_code)