github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-05-30 18:13:41 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

selftests: mm: add a test for remapping within a range

Browse Source 
Move a block of memory within a memory range.  Any alignment optimization
on the source address may cause corruption.  Verify using kselftest that
it works.  I have also verified with tracing that such optimization does
not happen due to this check in can_align_down():

if (!for_stack && vma->vm_start != addr_to_align)
	return false;

Link: https://lkml.kernel.org/r/20230903151328.2981432-7-joel@joelfernandes.org
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Joel Fernandes (Google) 2023-09-03 15:13:27 +00:00 committed by Andrew Morton
parent a4cb3b2433
commit 85a22845b0
1 changed files with 78 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

79
tools/testing/selftests/mm/mremap_test.c
View File

@ -23,6 +23,7 @@
#define VALIDATION_NO_THRESHOLD 0 /* Verify the entire region */
#define MIN(X, Y) ((X) < (Y) ? (X) : (Y))
#define SIZE_MB(m) ((size_t)m * (1024 * 1024))
struct config {
unsigned long long src_alignment;
@ -226,6 +227,79 @@ static void mremap_expand_merge_offset(FILE *maps_fp, unsigned long page_size)
ksft_test_result_fail("%s\n", test_name);
}
/*
* Verify that an mremap within a range does not cause corruption
* of unrelated part of range.
*
* Consider the following range which is 2MB aligned and is
* a part of a larger 20MB range which is not shown. Each
* character is 256KB below making the source and destination
* 2MB each. The lower case letters are moved (s to d) and the
* upper case letters are not moved. The below test verifies
* that the upper case S letters are not corrupted by the
* adjacent mremap.
*
* |DDDDddddSSSSssss|
*/
static void mremap_move_within_range(char pattern_seed)
{
char *test_name = "mremap mremap move within range";
void *src, *dest;
int i, success = 1;
size_t size = SIZE_MB(20);
void *ptr = mmap(NULL, size, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (ptr == MAP_FAILED) {
perror("mmap");
success = 0;
goto out;
}
memset(ptr, 0, size);
src = ptr + SIZE_MB(6);
src = (void *)((unsigned long)src & ~(SIZE_MB(2) - 1));
/* Set byte pattern for source block. */
srand(pattern_seed);
for (i = 0; i < SIZE_MB(2); i++) {
((char *)src)[i] = (char) rand();
}
dest = src - SIZE_MB(2);
void *new_ptr = mremap(src + SIZE_MB(1), SIZE_MB(1), SIZE_MB(1),
MREMAP_MAYMOVE | MREMAP_FIXED, dest + SIZE_MB(1));
if (new_ptr == MAP_FAILED) {
perror("mremap");
success = 0;
goto out;
}
/* Verify byte pattern after remapping */
srand(pattern_seed);
for (i = 0; i < SIZE_MB(1); i++) {
char c = (char) rand();
if (((char *)src)[i] != c) {
ksft_print_msg("Data at src at %d got corrupted due to unrelated mremap\n",
i);
ksft_print_msg("Expected: %#x\t Got: %#x\n", c & 0xff,
((char *) src)[i] & 0xff);
success = 0;
}
}
out:
if (munmap(ptr, size) == -1)
perror("munmap");
if (success)
ksft_test_result_pass("%s\n", test_name);
else
ksft_test_result_fail("%s\n", test_name);
}
/*
* Returns the start address of the mapping on success, else returns
* NULL on failure.
@ -491,6 +565,7 @@ int main(int argc, char **argv)
unsigned int threshold_mb = VALIDATION_DEFAULT_THRESHOLD;
unsigned int pattern_seed;
int num_expand_tests = 2;
int num_misc_tests = 1;
struct test test_cases[MAX_TEST] = {};
struct test perf_test_cases[MAX_PERF_TEST];
int page_size;
@ -572,7 +647,7 @@ int main(int argc, char **argv)
(threshold_mb * _1MB >= _1GB);
ksft_set_plan(ARRAY_SIZE(test_cases) + (run_perf_tests ?
ARRAY_SIZE(perf_test_cases) : 0) + num_expand_tests);
ARRAY_SIZE(perf_test_cases) : 0) + num_expand_tests + num_misc_tests);
for (i = 0; i < ARRAY_SIZE(test_cases); i++)
run_mremap_test_case(test_cases[i], &failures, threshold_mb,
@ -590,6 +665,8 @@ int main(int argc, char **argv)
fclose(maps_fp);
mremap_move_within_range(pattern_seed);
if (run_perf_tests) {
ksft_print_msg("\n%s\n",
"mremap HAVE_MOVE_PMD/PUD optimization time comparison for 1GB region:");