selftests/mm: skip soft-dirty tests when CONFIG_MEM_SOFT_DIRTY is disabled

commit 0389c305ef56cbadca4cbef44affc0ec3213ed30 upstream.

The madv_populate and soft-dirty kselftests currently fail on systems
where CONFIG_MEM_SOFT_DIRTY is disabled.

Introduce a new helper softdirty_supported() into vm_util.c/h to ensure
tests are properly skipped when the feature is not enabled.

Link: https://lkml.kernel.org/r/20250917133137.62802-1-lance.yang@linux.dev
Fixes: 9f3265db6ae8 ("selftests: vm: add test for Soft-Dirty PTE bit")
Signed-off-by: Lance Yang <lance.yang@linux.dev>
Acked-by: David Hildenbrand <david@redhat.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Gabriel Krisman Bertazi <krisman@collabora.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/tools/testing/selftests/vm/madv_populate.c b/tools/testing/selftests/vm/madv_populate.c
index 715a42e8e2cdb601bbc97d2c0cd05e8a7177e591..f37bda59c18c61e8989f18b1a21adfd404a80a64 100644 (file)
--- a/tools/testing/selftests/vm/madv_populate.c
+++ b/tools/testing/selftests/vm/madv_populate.c
@@ -274,12 +274,16 @@ static void test_softdirty(void)
 
 int main(int argc, char **argv)
 {
+       int nr_tests = 16;
        int err;
 
        pagesize = getpagesize();
 
+       if (softdirty_supported())
+               nr_tests += 5;
+
        ksft_print_header();
-       ksft_set_plan(21);
+       ksft_set_plan(nr_tests);
 
        sense_support();
        test_prot_read();
@@ -287,7 +291,8 @@ int main(int argc, char **argv)
        test_holes();
        test_populate_read();
        test_populate_write();
-       test_softdirty();
+       if (softdirty_supported())
+               test_softdirty();
 
        err = ksft_get_fail_cnt();
        if (err)

diff --git a/tools/testing/selftests/vm/soft-dirty.c b/tools/testing/selftests/vm/soft-dirty.c
index 21d8830c5f243aaf32a0b5eeae181775225056de..615ab2d204ef9fb9fc2827f4415419e4e6c6caf9 100644 (file)
--- a/tools/testing/selftests/vm/soft-dirty.c
+++ b/tools/testing/selftests/vm/soft-dirty.c
@@ -190,8 +190,11 @@ int main(int argc, char **argv)
        int pagesize;
 
        ksft_print_header();
-       ksft_set_plan(15);
 
+       if (!softdirty_supported())
+               ksft_exit_skip("soft-dirty is not support\n");
+
+       ksft_set_plan(15);
        pagemap_fd = open(PAGEMAP_FILE_PATH, O_RDONLY);
        if (pagemap_fd < 0)
                ksft_exit_fail_msg("Failed to open %s\n", PAGEMAP_FILE_PATH);

diff --git a/tools/testing/selftests/vm/vm_util.c b/tools/testing/selftests/vm/vm_util.c
index f11f8adda521867f52097aba2babca730941affa..fc5743bc1283e64aaab0193fe0d636ce22c4eb2a 100644 (file)
--- a/tools/testing/selftests/vm/vm_util.c
+++ b/tools/testing/selftests/vm/vm_util.c
@@ -72,6 +72,42 @@ uint64_t read_pmd_pagesize(void)
        return strtoul(buf, NULL, 10);
 }
 
+char *__get_smap_entry(void *addr, const char *pattern, char *buf, size_t len)
+{
+       int ret;
+       FILE *fp;
+       char *entry = NULL;
+       char addr_pattern[MAX_LINE_LENGTH];
+
+       ret = snprintf(addr_pattern, MAX_LINE_LENGTH, "%08lx-",
+                      (unsigned long)addr);
+       if (ret >= MAX_LINE_LENGTH)
+               ksft_exit_fail_msg("%s: Pattern is too long\n", __func__);
+
+       fp = fopen(SMAP_FILE_PATH, "r");
+       if (!fp)
+               ksft_exit_fail_msg("%s: Failed to open file %s\n", __func__,
+                                  SMAP_FILE_PATH);
+
+       if (!check_for_pattern(fp, addr_pattern, buf, len))
+               goto err_out;
+
+       /* Fetch the pattern in the same block */
+       if (!check_for_pattern(fp, pattern, buf, len))
+               goto err_out;
+
+       /* Trim trailing newline */
+       entry = strchr(buf, '\n');
+       if (entry)
+               *entry = '\0';
+
+       entry = buf + strlen(pattern);
+
+err_out:
+       fclose(fp);
+       return entry;
+}
+
 bool __check_huge(void *addr, char *pattern, int nr_hpages,
                  uint64_t hpage_size)
 {
@@ -124,3 +160,44 @@ bool check_huge_shmem(void *addr, int nr_hpages, uint64_t hpage_size)
 {
        return __check_huge(addr, "ShmemPmdMapped:", nr_hpages, hpage_size);
 }
+
+static bool check_vmflag(void *addr, const char *flag)
+{
+       char buffer[MAX_LINE_LENGTH];
+       const char *flags;
+       size_t flaglen;
+
+       flags = __get_smap_entry(addr, "VmFlags:", buffer, sizeof(buffer));
+       if (!flags)
+               ksft_exit_fail_msg("%s: No VmFlags for %p\n", __func__, addr);
+
+       while (true) {
+               flags += strspn(flags, " ");
+
+               flaglen = strcspn(flags, " ");
+               if (!flaglen)
+                       return false;
+
+               if (flaglen == strlen(flag) && !memcmp(flags, flag, flaglen))
+                       return true;
+
+               flags += flaglen;
+       }
+}
+
+bool softdirty_supported(void)
+{
+       char *addr;
+       bool supported = false;
+       const size_t pagesize = getpagesize();
+
+       /* New mappings are expected to be marked with VM_SOFTDIRTY (sd). */
+       addr = mmap(0, pagesize, PROT_READ | PROT_WRITE,
+                   MAP_ANONYMOUS | MAP_PRIVATE, 0, 0);
+       if (!addr)
+               ksft_exit_fail_msg("mmap failed\n");
+
+       supported = check_vmflag(addr, "sd");
+       munmap(addr, pagesize);
+       return supported;
+}

diff --git a/tools/testing/selftests/vm/vm_util.h b/tools/testing/selftests/vm/vm_util.h
index 5c35de454e08f33c22faa089f593d79fc3a4d0d2..470f85fe9594a63bf4f8ffe0d58d96920fa3f173 100644 (file)
--- a/tools/testing/selftests/vm/vm_util.h
+++ b/tools/testing/selftests/vm/vm_util.h
@@ -1,6 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0 */
 #include <stdint.h>
 #include <stdbool.h>
+#include <sys/mman.h>
 
 uint64_t pagemap_get_entry(int fd, char *start);
 bool pagemap_is_softdirty(int fd, char *start);
@@ -10,3 +11,4 @@ uint64_t read_pmd_pagesize(void);
 bool check_huge_anon(void *addr, int nr_hpages, uint64_t hpage_size);
 bool check_huge_file(void *addr, int nr_hpages, uint64_t hpage_size);
 bool check_huge_shmem(void *addr, int nr_hpages, uint64_t hpage_size);
+bool softdirty_supported(void);