[PATCH 5.10 47/71] selftest/vm: fix map_fixed_noreplace test failure

Greg Kroah-Hartman
2022-03-14T12:13:05Z

From: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>

[ Upstream commit f39c58008dee7ab5fc94c3f1995a21e886801df0 ]

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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
.../selftests/vm/map_fixed_noreplace.c | 49 ++++++++++++++-----
1 file changed, 37 insertions(+), 12 deletions(-)

diff --git a/tools/testing/selftests/vm/map_fixed_noreplace.c b/tools/testing/selftests/vm/map_fixed_noreplace.c
index d91bde511268..eed44322d1a6 100644
--- a/tools/testing/selftests/vm/map_fixed_noreplace.c
+++ b/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();
--
2.34.1