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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B4E52C4321E for ; Thu, 21 Apr 2022 23:35:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1442587AbiDUXir (ORCPT ); Thu, 21 Apr 2022 19:38:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40348 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1442588AbiDUXim (ORCPT ); Thu, 21 Apr 2022 19:38:42 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1747647044 for ; Thu, 21 Apr 2022 16:35:51 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 9F1A461EB9 for ; Thu, 21 Apr 2022 23:35:50 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F2D34C385A7; Thu, 21 Apr 2022 23:35:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1650584150; bh=jEX6oGkjPnokPyiiCeNv+6w1fLQkDgMbOZS5HSm4XnA=; h=Date:To:From:In-Reply-To:Subject:From; b=ihS8SOPygXy8lxXmcwfZZdl/YraysyI7OGe8Wf1G+4/nXTsWqNIgqSWmFen564aJH TTlD4IJ46Rd1SYmPVdaJ1aEUoRN4sWtkGHg+T7z8Oc+pdlHO6QTW9p4pfJQj2dDIO7 xjgYrAY0iOCD3CEFIsfsFIewFkvtJJrB51G+Gvk8= Date: Thu, 21 Apr 2022 16:35:49 -0700 To: skhan@linuxfoundation.org, sidhartha.kumar@oracle.com, akpm@linux-foundation.org, patches@lists.linux.dev, linux-mm@kvack.org, mm-commits@vger.kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org From: Andrew Morton In-Reply-To: <20220421163508.66028a9ac2d9fb6ea05b1342@linux-foundation.org> Subject: [patch 06/13] selftest/vm: verify mmap addr in mremap_test Message-Id: <20220421233549.F2D34C385A7@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: Sidhartha Kumar Subject: selftest/vm: verify mmap addr in mremap_test Avoid calling mmap with requested addresses that are less than the system's mmap_min_addr. When run as root, mmap returns EACCES when trying to map addresses < mmap_min_addr. This is not one of the error codes for the condition to retry the mmap in the test. Rather than arbitrarily retrying on EACCES, don't attempt an mmap until addr > vm.mmap_min_addr. Add a munmap call after an alignment check as the mappings are retained after the retry and can reach the vm.max_map_count sysctl. Link: https://lkml.kernel.org/r/20220420215721.4868-1-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar Reviewed-by: Shuah Khan Signed-off-by: Andrew Morton --- tools/testing/selftests/vm/mremap_test.c | 41 ++++++++++++++++++++- 1 file changed, 40 insertions(+), 1 deletion(-) --- a/tools/testing/selftests/vm/mremap_test.c~selftest-vm-verify-mmap-addr-in-mremap_test +++ a/tools/testing/selftests/vm/mremap_test.c @@ -6,6 +6,7 @@ #include #include +#include #include #include #include @@ -63,6 +64,35 @@ enum { .expect_failure = should_fail \ } +/* Returns mmap_min_addr sysctl tunable from procfs */ +static unsigned long long get_mmap_min_addr(void) +{ + FILE *fp; + int n_matched; + static unsigned long long addr; + + if (addr) + return addr; + + fp = fopen("/proc/sys/vm/mmap_min_addr", "r"); + if (fp == NULL) { + ksft_print_msg("Failed to open /proc/sys/vm/mmap_min_addr: %s\n", + strerror(errno)); + exit(KSFT_SKIP); + } + + n_matched = fscanf(fp, "%llu", &addr); + if (n_matched != 1) { + ksft_print_msg("Failed to read /proc/sys/vm/mmap_min_addr: %s\n", + strerror(errno)); + fclose(fp); + exit(KSFT_SKIP); + } + + fclose(fp); + return addr; +} + /* * Returns the start address of the mapping on success, else returns * NULL on failure. @@ -71,8 +101,15 @@ static void *get_source_mapping(struct c { unsigned long long addr = 0ULL; void *src_addr = NULL; + unsigned long long mmap_min_addr; + + mmap_min_addr = get_mmap_min_addr(); + retry: addr += c.src_alignment; + if (addr < mmap_min_addr) + goto retry; + src_addr = mmap((void *) addr, c.region_size, PROT_READ | PROT_WRITE, MAP_FIXED_NOREPLACE | MAP_ANONYMOUS | MAP_SHARED, -1, 0); @@ -90,8 +127,10 @@ retry: * alignment in the tests. */ if (((unsigned long long) src_addr & (c.src_alignment - 1)) || - !((unsigned long long) src_addr & c.src_alignment)) + !((unsigned long long) src_addr & c.src_alignment)) { + munmap(src_addr, c.region_size); goto retry; + } if (!src_addr) goto error; _