From: Andrew Morton <akpm@linux-foundation.org> 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 Subject: [patch 06/13] selftest/vm: verify mmap addr in mremap_test Date: Thu, 21 Apr 2022 16:35:49 -0700 [thread overview] Message-ID: <20220421233549.F2D34C385A7@smtp.kernel.org> (raw) In-Reply-To: <20220421163508.66028a9ac2d9fb6ea05b1342@linux-foundation.org> From: Sidhartha Kumar <sidhartha.kumar@oracle.com> 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 <sidhartha.kumar@oracle.com> Reviewed-by: Shuah Khan <skhan@linuxfoundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> --- 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 <errno.h> #include <stdlib.h> +#include <stdio.h> #include <string.h> #include <sys/mman.h> #include <time.h> @@ -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; _
WARNING: multiple messages have this Message-ID (diff)
From: Andrew Morton <akpm@linux-foundation.org> 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 Subject: [patch 06/13] selftest/vm: verify mmap addr in mremap_test Date: Thu, 21 Apr 2022 16:35:49 -0700 [thread overview] Message-ID: <20220421233549.F2D34C385A7@smtp.kernel.org> (raw) In-Reply-To: <20220421163508.66028a9ac2d9fb6ea05b1342@linux-foundation.org> From: Sidhartha Kumar <sidhartha.kumar@oracle.com> 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 <sidhartha.kumar@oracle.com> Reviewed-by: Shuah Khan <skhan@linuxfoundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> --- 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 <errno.h> #include <stdlib.h> +#include <stdio.h> #include <string.h> #include <sys/mman.h> #include <time.h> @@ -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; _
next prev parent reply other threads:[~2022-04-21 23:35 UTC|newest] Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-04-21 23:35 incoming Andrew Morton 2022-04-21 23:35 ` [patch 01/13] mm/hwpoison: fix race between hugetlb free/demotion and memory_failure_hugetlb() Andrew Morton 2022-04-21 23:35 ` Andrew Morton 2022-04-21 23:35 ` [patch 02/13] mm/memory-failure.c: skip huge_zero_page in memory_failure() Andrew Morton 2022-04-21 23:35 ` Andrew Morton 2022-04-21 23:35 ` [patch 03/13] memcg: sync flush only if periodic flush is delayed Andrew Morton 2022-04-21 23:35 ` Andrew Morton 2022-04-21 23:35 ` [patch 04/13] userfaultfd: mark uffd_wp regardless of VM_WRITE flag Andrew Morton 2022-04-21 23:35 ` Andrew Morton 2022-04-21 23:35 ` [patch 05/13] mm, hugetlb: allow for "high" userspace addresses Andrew Morton 2022-04-21 23:35 ` Andrew Morton 2022-04-21 23:35 ` Andrew Morton [this message] 2022-04-21 23:35 ` [patch 06/13] selftest/vm: verify mmap addr in mremap_test Andrew Morton 2022-04-21 23:35 ` [patch 07/13] selftest/vm: verify remap destination address " Andrew Morton 2022-04-21 23:35 ` Andrew Morton 2022-04-21 23:35 ` [patch 08/13] selftest/vm: support xfail " Andrew Morton 2022-04-21 23:35 ` Andrew Morton 2022-04-21 23:35 ` [patch 09/13] selftest/vm: add skip support to mremap_test Andrew Morton 2022-04-21 23:35 ` Andrew Morton 2022-04-21 23:36 ` [patch 10/13] oom_kill.c: futex: delay the OOM reaper to allow time for proper futex cleanup Andrew Morton 2022-04-21 23:36 ` Andrew Morton 2022-04-21 23:36 ` [patch 11/13] MAINTAINERS: add Vincenzo Frascino to KASAN reviewers Andrew Morton 2022-04-21 23:36 ` Andrew Morton 2022-04-21 23:36 ` [patch 12/13] kcov: don't generate a warning on vm_insert_page()'s failure Andrew Morton 2022-04-21 23:36 ` Andrew Morton 2022-04-21 23:36 ` [patch 13/13] mm/mmu_notifier.c: fix race in mmu_interval_notifier_remove() Andrew Morton 2022-04-21 23:36 ` Andrew Morton
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