6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Lance Yang lance.yang@linux.dev
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 --- tools/testing/selftests/mm/madv_populate.c | 21 ------- tools/testing/selftests/mm/soft-dirty.c | 5 + tools/testing/selftests/mm/vm_util.c | 77 +++++++++++++++++++++++++++++ tools/testing/selftests/mm/vm_util.h | 1 4 files changed, 84 insertions(+), 20 deletions(-)
--- a/tools/testing/selftests/mm/madv_populate.c +++ b/tools/testing/selftests/mm/madv_populate.c @@ -264,23 +264,6 @@ static void test_softdirty(void) munmap(addr, SIZE); }
-static int system_has_softdirty(void) -{ - /* - * There is no way to check if the kernel supports soft-dirty, other - * than by writing to a page and seeing if the bit was set. But the - * tests are intended to check that the bit gets set when it should, so - * doing that check would turn a potentially legitimate fail into a - * skip. Fortunately, we know for sure that arm64 does not support - * soft-dirty. So for now, let's just use the arch as a corse guide. - */ -#if defined(__aarch64__) - return 0; -#else - return 1; -#endif -} - int main(int argc, char **argv) { int nr_tests = 16; @@ -288,7 +271,7 @@ int main(int argc, char **argv)
pagesize = getpagesize();
- if (system_has_softdirty()) + if (softdirty_supported()) nr_tests += 5;
ksft_print_header(); @@ -300,7 +283,7 @@ int main(int argc, char **argv) test_holes(); test_populate_read(); test_populate_write(); - if (system_has_softdirty()) + if (softdirty_supported()) test_softdirty();
err = ksft_get_fail_cnt(); --- a/tools/testing/selftests/mm/soft-dirty.c +++ b/tools/testing/selftests/mm/soft-dirty.c @@ -193,8 +193,11 @@ 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); --- a/tools/testing/selftests/mm/vm_util.c +++ b/tools/testing/selftests/mm/vm_util.c @@ -193,6 +193,42 @@ err_out: return rss_anon; }
+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) { @@ -384,3 +420,44 @@ unsigned long get_free_hugepages(void) fclose(f); return fhp; } + +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; +} --- a/tools/testing/selftests/mm/vm_util.h +++ b/tools/testing/selftests/mm/vm_util.h @@ -53,6 +53,7 @@ int uffd_unregister(int uffd, void *addr int uffd_register_with_ioctls(int uffd, void *addr, uint64_t len, bool miss, bool wp, bool minor, uint64_t *ioctls); unsigned long get_free_hugepages(void); +bool softdirty_supported(void);
/* * On ppc64 this will only work with radix 2M hugepage size