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selftest/vm: fix map_fixed_noreplace test failure
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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/[email protected]
Signed-off-by: Aneesh Kumar K.V <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Jann Horn <[email protected]>
Cc: Shuah Khan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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@kvaneesh @torvalds
kvaneesh authored and torvalds committed Feb 26, 2022
1 parent f798a1d commit f39c580
Showing 1 changed file with 37 additions and 12 deletions.
49 changes: 37 additions & 12 deletions tools/testing/selftests/vm/map_fixed_noreplace.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -17,9 +17,6 @@
#define MAP_FIXED_NOREPLACE 0x100000
#endif

#define BASE_ADDRESS (256ul * 1024 * 1024)


static void dump_maps(void)
{
char cmd[32];
Expand All @@ -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);

Expand All @@ -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);
Expand All @@ -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);
Expand All @@ -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);
Expand All @@ -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);
Expand All @@ -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);
Expand All @@ -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);
Expand All @@ -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);
Expand All @@ -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();
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