From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 93495C28CF8 for ; Sat, 13 Oct 2018 13:40:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4C00420895 for ; Sat, 13 Oct 2018 13:40:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4C00420895 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726636AbeJMVRR (ORCPT ); Sat, 13 Oct 2018 17:17:17 -0400 Received: from ozlabs.org ([203.11.71.1]:33541 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726281AbeJMVRR (ORCPT ); Sat, 13 Oct 2018 17:17:17 -0400 Received: by ozlabs.org (Postfix, from userid 1034) id 42XQmz5rwkz9sCW; Sun, 14 Oct 2018 00:40:03 +1100 (AEDT) From: Michael Ellerman To: akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, jannh@google.com, mhocko@suse.com, linux-mm@kvack.org, khalid.aziz@oracle.com, aarcange@redhat.com, fweimer@redhat.com, jhubbard@nvidia.com, willy@infradead.org, abdhalee@linux.vnet.ibm.com, joel@jms.id.au, keescook@chromium.org, jasone@google.com, davidtgoldblatt@gmail.com, trasz@freebsd.org, danielmicay@gmail.com Subject: [PATCH] selftests/vm: Add a test for MAP_FIXED_NOREPLACE Date: Sun, 14 Oct 2018 00:39:29 +1100 Message-Id: <20181013133929.28653-1-mpe@ellerman.id.au> X-Mailer: git-send-email 2.17.1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add a test for MAP_FIXED_NOREPLACE, based on some code originally by Jann Horn. This would have caught the overlap bug reported by Daniel Micay. I originally suggested to Michal that we create MAP_FIXED_NOREPLACE, but instead of writing a selftest I spent my time bike-shedding whether it should be called MAP_FIXED_SAFE/NOCLOBBER/WEAK/NEW .. mea culpa. Signed-off-by: Michael Ellerman --- tools/testing/selftests/vm/.gitignore | 1 + tools/testing/selftests/vm/Makefile | 1 + .../selftests/vm/map_fixed_noreplace.c | 206 ++++++++++++++++++ 3 files changed, 208 insertions(+) create mode 100644 tools/testing/selftests/vm/map_fixed_noreplace.c diff --git a/tools/testing/selftests/vm/.gitignore b/tools/testing/selftests/vm/.gitignore index af5ff83f6d7f..31b3c98b6d34 100644 --- a/tools/testing/selftests/vm/.gitignore +++ b/tools/testing/selftests/vm/.gitignore @@ -13,3 +13,4 @@ mlock-random-test virtual_address_range gup_benchmark va_128TBswitch +map_fixed_noreplace diff --git a/tools/testing/selftests/vm/Makefile b/tools/testing/selftests/vm/Makefile index e94b7b14bcb2..6e67e726e5a5 100644 --- a/tools/testing/selftests/vm/Makefile +++ b/tools/testing/selftests/vm/Makefile @@ -12,6 +12,7 @@ TEST_GEN_FILES += gup_benchmark TEST_GEN_FILES += hugepage-mmap TEST_GEN_FILES += hugepage-shm TEST_GEN_FILES += map_hugetlb +TEST_GEN_FILES += map_fixed_noreplace TEST_GEN_FILES += map_populate TEST_GEN_FILES += mlock-random-test TEST_GEN_FILES += mlock2-tests diff --git a/tools/testing/selftests/vm/map_fixed_noreplace.c b/tools/testing/selftests/vm/map_fixed_noreplace.c new file mode 100644 index 000000000000..d91bde511268 --- /dev/null +++ b/tools/testing/selftests/vm/map_fixed_noreplace.c @@ -0,0 +1,206 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Test that MAP_FIXED_NOREPLACE works. + * + * Copyright 2018, Jann Horn + * Copyright 2018, Michael Ellerman, IBM Corporation. + */ + +#include +#include +#include +#include +#include + +#ifndef MAP_FIXED_NOREPLACE +#define MAP_FIXED_NOREPLACE 0x100000 +#endif + +#define BASE_ADDRESS (256ul * 1024 * 1024) + + +static void dump_maps(void) +{ + char cmd[32]; + + snprintf(cmd, sizeof(cmd), "cat /proc/%d/maps", getpid()); + system(cmd); +} + +int main(void) +{ + unsigned long flags, addr, size, page_size; + char *p; + + page_size = sysconf(_SC_PAGE_SIZE); + + flags = MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED_NOREPLACE; + + // Check we can map all the areas we need below + errno = 0; + addr = BASE_ADDRESS; + size = 5 * page_size; + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); + + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); + + if (p == MAP_FAILED) { + dump_maps(); + printf("Error: couldn't map the space we need for the test\n"); + return 1; + } + + errno = 0; + if (munmap((void *)addr, 5 * page_size) != 0) { + dump_maps(); + printf("Error: munmap failed!?\n"); + return 1; + } + printf("unmap() successful\n"); + + errno = 0; + addr = BASE_ADDRESS + page_size; + size = 3 * page_size; + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); + + if (p == MAP_FAILED) { + dump_maps(); + printf("Error: first mmap() failed unexpectedly\n"); + return 1; + } + + /* + * Exact same mapping again: + * base | free | new + * +1 | mapped | new + * +2 | mapped | new + * +3 | mapped | new + * +4 | free | new + */ + errno = 0; + addr = BASE_ADDRESS; + size = 5 * page_size; + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); + + if (p != MAP_FAILED) { + dump_maps(); + printf("Error:1: mmap() succeeded when it shouldn't have\n"); + return 1; + } + + /* + * Second mapping contained within first: + * + * base | free | + * +1 | mapped | + * +2 | mapped | new + * +3 | mapped | + * +4 | free | + */ + errno = 0; + addr = BASE_ADDRESS + (2 * page_size); + size = page_size; + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); + + if (p != MAP_FAILED) { + dump_maps(); + printf("Error:2: mmap() succeeded when it shouldn't have\n"); + return 1; + } + + /* + * Overlap end of existing mapping: + * base | free | + * +1 | mapped | + * +2 | mapped | + * +3 | mapped | new + * +4 | free | new + */ + errno = 0; + addr = BASE_ADDRESS + (3 * page_size); + size = 2 * page_size; + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); + + if (p != MAP_FAILED) { + dump_maps(); + printf("Error:3: mmap() succeeded when it shouldn't have\n"); + return 1; + } + + /* + * Overlap start of existing mapping: + * base | free | new + * +1 | mapped | new + * +2 | mapped | + * +3 | mapped | + * +4 | free | + */ + errno = 0; + addr = BASE_ADDRESS; + size = 2 * page_size; + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); + + if (p != MAP_FAILED) { + dump_maps(); + printf("Error:4: mmap() succeeded when it shouldn't have\n"); + return 1; + } + + /* + * Adjacent to start of existing mapping: + * base | free | new + * +1 | mapped | + * +2 | mapped | + * +3 | mapped | + * +4 | free | + */ + errno = 0; + addr = BASE_ADDRESS; + size = page_size; + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); + + if (p == MAP_FAILED) { + dump_maps(); + printf("Error:5: mmap() failed when it shouldn't have\n"); + return 1; + } + + /* + * Adjacent to end of existing mapping: + * base | free | + * +1 | mapped | + * +2 | mapped | + * +3 | mapped | + * +4 | free | new + */ + errno = 0; + addr = BASE_ADDRESS + (4 * page_size); + size = page_size; + p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0); + printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p); + + if (p == MAP_FAILED) { + dump_maps(); + printf("Error:6: mmap() failed when it shouldn't have\n"); + return 1; + } + + addr = BASE_ADDRESS; + size = 5 * page_size; + if (munmap((void *)addr, size) != 0) { + dump_maps(); + printf("Error: munmap failed!?\n"); + return 1; + } + printf("unmap() successful\n"); + + printf("OK\n"); + return 0; +} -- 2.17.1