From patchwork Thu May 11 18:24:26 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Axel Rasmussen X-Patchwork-Id: 13238353 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8FC33C7EE24 for ; Thu, 11 May 2023 18:25:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238838AbjEKSY6 (ORCPT ); Thu, 11 May 2023 14:24:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47634 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238903AbjEKSYj (ORCPT ); Thu, 11 May 2023 14:24:39 -0400 Received: from mail-yb1-xb4a.google.com (mail-yb1-xb4a.google.com [IPv6:2607:f8b0:4864:20::b4a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CE304558D for ; Thu, 11 May 2023 11:24:37 -0700 (PDT) Received: by mail-yb1-xb4a.google.com with SMTP id 3f1490d57ef6-b9a7e65b34aso16106013276.0 for ; Thu, 11 May 2023 11:24:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1683829477; x=1686421477; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=pXR2gVK9OA+wwjaEDZ+OSGVT3sLd4z3OrzMBakd4aKc=; b=uljCWBeUfmKO+5Of2CDGdnripKh0c8Rzx0Uw+3mUJQMB0vkRyYLVzF+n17pnlhk/Gx 5bJy3V1jOgdbwhD+IzTsmSPyo+npOvf5g9Bg01qvgjSMD6eTNJAt18pXpgDdOP/1R0pG f7W9dTJmQptgBrJNb6rZO42eQOqXUPeL3PmdMoDvsc0jIKFazxlaZQy6iFcTAKrcyb2g Vd4Xof1tpuhpdbe6fUAhZyOPuYJwlVtphMWQs8q/tSYp7h7umSFg6RazMw4joPD08IQq U+PE0b8W/rQAZMz7pnNUhXYfuSp6KyH2zv92pJQFwOvAqZixv97KJ+4OltRNsi03yCWr atQw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1683829477; x=1686421477; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=pXR2gVK9OA+wwjaEDZ+OSGVT3sLd4z3OrzMBakd4aKc=; b=RIrkmnruJNYZU5l3cjEFAmEe68XcvGpj4E6gHlCSFFBB0zaHyfnPTOwnob3S17uccR rz5f608ruQBvwWnXIhBnzl+e8HwWjgeRg0ID7MEcOKDMRiiqQFRoIg7E/q5M6t4z196K Pl34nmJ1RO8da2tHuCT+t64HKyVqJtOO8Mae7XJa4DDAoMN9dH/wlQCmTeJMajCF1VSB 4zbPQFC90gZcZSCxGyOyP18JSEEQ9yzADkreiAeG0vUiRmKJy7lfwxlcogAHH5rz4eDm IWCequ7UoSNc+ld/IW3Y6V/KMEJCcJshSScxxYCYFEHxbcWfxOc9zXoRehx/jdnw6UHa +TOQ== X-Gm-Message-State: AC+VfDxfc/sa2gbXXAxs+1hezb8SDnuL8XYhqWg+BqbSoiz1I2m10roG HebJsGiLA/nea0GOCvBU2cHii8hN3fLo0rrQ/T0o X-Google-Smtp-Source: ACHHUZ6/k8WRFVr95FNBEjmhvpwsN42OkGFLi7clqHCCS0gOIKkyVoZZe1vIA3bGUQMYYdRD+oFyrl83UA1YRSgN8vJE X-Received: from axel.svl.corp.google.com ([2620:15c:2d4:203:1119:8675:ddb3:1e7a]) (user=axelrasmussen job=sendgmr) by 2002:a05:6902:114e:b0:b4a:3896:bc17 with SMTP id p14-20020a056902114e00b00b4a3896bc17mr9915667ybu.0.1683829477159; Thu, 11 May 2023 11:24:37 -0700 (PDT) Date: Thu, 11 May 2023 11:24:26 -0700 In-Reply-To: <20230511182426.1898675-1-axelrasmussen@google.com> Mime-Version: 1.0 References: <20230511182426.1898675-1-axelrasmussen@google.com> X-Mailer: git-send-email 2.40.1.606.ga4b1b128d6-goog Message-ID: <20230511182426.1898675-3-axelrasmussen@google.com> Subject: [PATCH 3/3] selftests/mm: add uffd unit test for UFFDIO_SIGBUS From: Axel Rasmussen To: Alexander Viro , Andrew Morton , Christian Brauner , David Hildenbrand , Hongchen Zhang , Huang Ying , James Houghton , "Liam R. Howlett" , Miaohe Lin , "Mike Rapoport (IBM)" , Nadav Amit , Naoya Horiguchi , Peter Xu , Shuah Khan , ZhangPeng Cc: Axel Rasmussen , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org The test is pretty basic, and exercises UFFDIO_SIGBUS straightforwardly. We register a region with userfaultfd, in missing fault mode. For each fault, we either issue UFFDIO_ZEROPAGE (odd pages) or UFFDIO_SIGBUS (even pages). We read each page in the region, and assert that the odd pages are zeroed as expected, and the even pages yield a SIGBUS as expected. Signed-off-by: Axel Rasmussen --- tools/testing/selftests/mm/uffd-unit-tests.c | 114 ++++++++++++++++++- 1 file changed, 110 insertions(+), 4 deletions(-) diff --git a/tools/testing/selftests/mm/uffd-unit-tests.c b/tools/testing/selftests/mm/uffd-unit-tests.c index 269c86768a02..3eb5a6f9b51f 100644 --- a/tools/testing/selftests/mm/uffd-unit-tests.c +++ b/tools/testing/selftests/mm/uffd-unit-tests.c @@ -881,13 +881,13 @@ static void retry_uffdio_zeropage(int ufd, } } -static bool do_uffdio_zeropage(int ufd, bool has_zeropage) +static bool do_uffdio_zeropage(int ufd, bool has_zeropage, bool test_retry, unsigned long offset) { struct uffdio_zeropage uffdio_zeropage = { 0 }; int ret; __s64 res; - uffdio_zeropage.range.start = (unsigned long) area_dst; + uffdio_zeropage.range.start = (unsigned long) area_dst + offset; uffdio_zeropage.range.len = page_size; uffdio_zeropage.mode = 0; ret = ioctl(ufd, UFFDIO_ZEROPAGE, &uffdio_zeropage); @@ -901,7 +901,7 @@ static bool do_uffdio_zeropage(int ufd, bool has_zeropage) } else if (has_zeropage) { if (res != page_size) err("UFFDIO_ZEROPAGE unexpected size"); - else + else if (test_retry) retry_uffdio_zeropage(ufd, &uffdio_zeropage); return true; } else @@ -938,7 +938,7 @@ static void uffd_zeropage_test(uffd_test_args_t *args) /* Ignore the retval; we already have it */ uffd_register_detect_zeropage(uffd, area_dst_alias, page_size); - if (do_uffdio_zeropage(uffd, has_zeropage)) + if (do_uffdio_zeropage(uffd, has_zeropage, true, 0)) for (i = 0; i < page_size; i++) if (area_dst[i] != 0) err("data non-zero at offset %d\n", i); @@ -952,6 +952,106 @@ static void uffd_zeropage_test(uffd_test_args_t *args) uffd_test_pass(); } +static void do_uffdio_sigbus(int uffd, unsigned long offset) +{ + struct uffdio_sigbus uffdio_sigbus = { 0 }; + int ret; + __s64 res; + + uffdio_sigbus.range.start = (unsigned long) area_dst + offset; + uffdio_sigbus.range.len = page_size; + uffdio_sigbus.mode = 0; + ret = ioctl(uffd, UFFDIO_SIGBUS, &uffdio_sigbus); + res = uffdio_sigbus.updated; + + if (ret) + err("UFFDIO_SIGBUS error: %"PRId64, (int64_t)res); + else if (res != page_size) + err("UFFDIO_SIGBUS unexpected size: %"PRId64, (int64_t)res); +} + +static void uffd_sigbus_ioctl_handle_fault( + struct uffd_msg *msg, struct uffd_args *args) +{ + unsigned long offset; + + if (msg->event != UFFD_EVENT_PAGEFAULT) + err("unexpected msg event %u", msg->event); + + if (msg->arg.pagefault.flags & + (UFFD_PAGEFAULT_FLAG_WP | UFFD_PAGEFAULT_FLAG_MINOR)) + err("unexpected fault type %llu", msg->arg.pagefault.flags); + + offset = (char *)(unsigned long)msg->arg.pagefault.address - area_dst; + offset &= ~(page_size-1); + + /* Odd pages -> zeropage; even pages -> sigbus. */ + if (offset & page_size) { + if (!do_uffdio_zeropage(uffd, true, false, offset)) + err("UFFDIO_ZEROPAGE failed"); + } else { + do_uffdio_sigbus(uffd, offset); + } +} + +static void uffd_sigbus_ioctl_test(uffd_test_args_t *targs) +{ + pthread_t uffd_mon; + char c; + struct uffd_args args = { 0 }; + struct sigaction act = { 0 }; + unsigned long nr_sigbus = 0; + unsigned long nr; + + fcntl(uffd, F_SETFL, uffd_flags | O_NONBLOCK); + + if (!uffd_register_detect_zeropage(uffd, area_dst, nr_pages * page_size)) + err("register failed: no zeropage support"); + + args.handle_fault = uffd_sigbus_ioctl_handle_fault; + if (pthread_create(&uffd_mon, NULL, uffd_poll_thread, &args)) + err("uffd_poll_thread create"); + + sigbuf = &jbuf; + act.sa_sigaction = sighndl; + act.sa_flags = SA_SIGINFO; + if (sigaction(SIGBUS, &act, 0)) + err("sigaction"); + + for (nr = 0; nr < nr_pages; ++nr) { + unsigned long offset = nr * page_size; + const char *bytes = (const char *) area_dst + offset; + const char *i; + + if (sigsetjmp(*sigbuf, 1)) { + /* + * Access below triggered a SIGBUS, which was caught by + * sighndl, which then jumped here. Count this SIGBUS, + * and move on to next page. + */ + ++nr_sigbus; + continue; + } + + for (i = bytes; i < bytes + page_size; ++i) { + if (*i) + err("nonzero byte in area_dst (%p) at %p: %u", + area_dst, i, *i); + } + } + + if (write(pipefd[1], &c, sizeof(c)) != sizeof(c)) + err("pipe write"); + if (pthread_join(uffd_mon, NULL)) + err("pthread_join()"); + + if (nr_sigbus != nr_pages / 2) + err("expected to receive %lu SIGBUS, actually received %lu", + nr_pages / 2, nr_sigbus); + + uffd_test_pass(); +} + /* * Test the returned uffdio_register.ioctls with different register modes. * Note that _UFFDIO_ZEROPAGE is tested separately in the zeropage test. @@ -1127,6 +1227,12 @@ uffd_test_case_t uffd_tests[] = { UFFD_FEATURE_PAGEFAULT_FLAG_WP | UFFD_FEATURE_WP_HUGETLBFS_SHMEM, }, + { + .name = "sigbus-ioctl", + .uffd_fn = uffd_sigbus_ioctl_test, + .mem_targets = MEM_ALL & ~(MEM_HUGETLB | MEM_HUGETLB_PRIVATE), + .uffd_feature_required = UFFD_FEATURE_SIGBUS_IOCTL, + }, }; static void usage(const char *prog)