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From: Andrew Morton <akpm@linux-foundation.org>
To: shuah@kernel.org, mpe@ellerman.id.au, jannh@google.com,
	aneesh.kumar@linux.ibm.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 06/12] selftest/vm: fix map_fixed_noreplace test failure
Date: Fri, 25 Feb 2022 19:11:08 -0800	[thread overview]
Message-ID: <20220226031109.863D5C340E7@smtp.kernel.org> (raw)
In-Reply-To: <20220225191021.f71538a3f43dc448110e88b6@linux-foundation.org>

From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Subject: selftest/vm: fix map_fixed_noreplace test failure

On the latest RHEL the test fails due to executable mapped at 256MB address

 # ./map_fixed_noreplace
mmap() @ 0x10000000-0x10050000 p=0xffffffffffffffff result=File exists
10000000-10010000 r-xp 00000000 fd:04 34905657                           /root/rpmbuild/BUILD/kernel-5.14.0-56.el9/linux-5.14.0-56.el9.ppc64le/tools/testing/selftests/vm/map_fixed_noreplace
10010000-10020000 r--p 00000000 fd:04 34905657                           /root/rpmbuild/BUILD/kernel-5.14.0-56.el9/linux-5.14.0-56.el9.ppc64le/tools/testing/selftests/vm/map_fixed_noreplace
10020000-10030000 rw-p 00010000 fd:04 34905657                           /root/rpmbuild/BUILD/kernel-5.14.0-56.el9/linux-5.14.0-56.el9.ppc64le/tools/testing/selftests/vm/map_fixed_noreplace
10029b90000-10029bc0000 rw-p 00000000 00:00 0                            [heap]
7fffbb510000-7fffbb750000 r-xp 00000000 fd:04 24534                      /usr/lib64/libc.so.6
7fffbb750000-7fffbb760000 r--p 00230000 fd:04 24534                      /usr/lib64/libc.so.6
7fffbb760000-7fffbb770000 rw-p 00240000 fd:04 24534                      /usr/lib64/libc.so.6
7fffbb780000-7fffbb7a0000 r--p 00000000 00:00 0                          [vvar]
7fffbb7a0000-7fffbb7b0000 r-xp 00000000 00:00 0                          [vdso]
7fffbb7b0000-7fffbb800000 r-xp 00000000 fd:04 24514                      /usr/lib64/ld64.so.2
7fffbb800000-7fffbb810000 r--p 00040000 fd:04 24514                      /usr/lib64/ld64.so.2
7fffbb810000-7fffbb820000 rw-p 00050000 fd:04 24514                      /usr/lib64/ld64.so.2
7fffd93f0000-7fffd9420000 rw-p 00000000 00:00 0                          [stack]
Error: couldn't map the space we need for the test

Fix this by finding a free address using mmap instead of hardcoding BASE_ADDRESS.

Link: https://lkml.kernel.org/r/20220217083417.373823-1-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Jann Horn <jannh@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 tools/testing/selftests/vm/map_fixed_noreplace.c |   49 +++++++++----
 1 file changed, 37 insertions(+), 12 deletions(-)

--- a/tools/testing/selftests/vm/map_fixed_noreplace.c~selftest-vm-fix-map_fixed_noreplace-test-failure
+++ a/tools/testing/selftests/vm/map_fixed_noreplace.c
@@ -17,9 +17,6 @@
 #define MAP_FIXED_NOREPLACE 0x100000
 #endif
 
-#define BASE_ADDRESS	(256ul * 1024 * 1024)
-
-
 static void dump_maps(void)
 {
 	char cmd[32];
@@ -28,18 +25,46 @@ static void dump_maps(void)
 	system(cmd);
 }
 
+static unsigned long find_base_addr(unsigned long size)
+{
+	void *addr;
+	unsigned long flags;
+
+	flags = MAP_PRIVATE | MAP_ANONYMOUS;
+	addr = mmap(NULL, size, PROT_NONE, flags, -1, 0);
+	if (addr == MAP_FAILED) {
+		printf("Error: couldn't map the space we need for the test\n");
+		return 0;
+	}
+
+	if (munmap(addr, size) != 0) {
+		printf("Error: couldn't map the space we need for the test\n");
+		return 0;
+	}
+	return (unsigned long)addr;
+}
+
 int main(void)
 {
+	unsigned long base_addr;
 	unsigned long flags, addr, size, page_size;
 	char *p;
 
 	page_size = sysconf(_SC_PAGE_SIZE);
 
+	//let's find a base addr that is free before we start the tests
+	size = 5 * page_size;
+	base_addr = find_base_addr(size);
+	if (!base_addr) {
+		printf("Error: couldn't map the space we need for the test\n");
+		return 1;
+	}
+
 	flags = MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED_NOREPLACE;
 
 	// Check we can map all the areas we need below
 	errno = 0;
-	addr = BASE_ADDRESS;
+	addr = base_addr;
 	size = 5 * page_size;
 	p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0);
 
@@ -60,7 +85,7 @@ int main(void)
 	printf("unmap() successful\n");
 
 	errno = 0;
-	addr = BASE_ADDRESS + page_size;
+	addr = base_addr + 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);
@@ -80,7 +105,7 @@ int main(void)
 	 *     +4 |  free  | new
 	 */
 	errno = 0;
-	addr = BASE_ADDRESS;
+	addr = base_addr;
 	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);
@@ -101,7 +126,7 @@ int main(void)
 	 *     +4 |  free  |
 	 */
 	errno = 0;
-	addr = BASE_ADDRESS + (2 * page_size);
+	addr = base_addr + (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);
@@ -121,7 +146,7 @@ int main(void)
 	 *     +4 |  free  | new
 	 */
 	errno = 0;
-	addr = BASE_ADDRESS + (3 * page_size);
+	addr = base_addr + (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);
@@ -141,7 +166,7 @@ int main(void)
 	 *     +4 |  free  |
 	 */
 	errno = 0;
-	addr = BASE_ADDRESS;
+	addr = base_addr;
 	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);
@@ -161,7 +186,7 @@ int main(void)
 	 *     +4 |  free  |
 	 */
 	errno = 0;
-	addr = BASE_ADDRESS;
+	addr = base_addr;
 	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);
@@ -181,7 +206,7 @@ int main(void)
 	 *     +4 |  free  |  new
 	 */
 	errno = 0;
-	addr = BASE_ADDRESS + (4 * page_size);
+	addr = base_addr + (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);
@@ -192,7 +217,7 @@ int main(void)
 		return 1;
 	}
 
-	addr = BASE_ADDRESS;
+	addr = base_addr;
 	size = 5 * page_size;
 	if (munmap((void *)addr, size) != 0) {
 		dump_maps();
_

  parent reply	other threads:[~2022-02-26  3:11 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-26  3:10 incoming Andrew Morton
2022-02-26  3:10 ` [patch 01/12] MAINTAINERS: add sysctl-next git tree Andrew Morton
2022-02-26  3:10 ` [patch 02/12] mm/hugetlb: fix kernel crash with hugetlb mremap Andrew Morton
2022-02-26  3:10 ` [patch 03/12] kasan: test: prevent cache merging in kmem_cache_double_destroy Andrew Morton
2022-02-26  3:11 ` [patch 04/12] hugetlbfs: fix a truncation issue in hugepages parameter Andrew Morton
2022-02-26  3:11 ` [patch 05/12] mm: fix use-after-free bug when mm->mmap is reused after being freed Andrew Morton
2022-02-26  3:11 ` Andrew Morton [this message]
2022-02-26  3:11 ` [patch 07/12] MAINTAINERS: add Roman as a memcg co-maintainer Andrew Morton
2022-02-26  3:11 ` [patch 08/12] MAINTAINERS: remove Vladimir from memcg maintainers Andrew Morton
2022-02-26  3:11 ` [patch 09/12] MAINTAINERS: add Shakeel as a memcg co-maintainer Andrew Morton
2022-02-26  3:11 ` [patch 10/12] MAINTAINERS, SLAB: add Roman as reviewer, git tree Andrew Morton
2022-02-26  3:11 ` [patch 11/12] mailmap: update Roman Gushchin's email Andrew Morton
2022-02-26  3:11 ` [patch 12/12] selftests/memfd: clean up mapping in mfd_fail_write Andrew Morton

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