Merge: selftests/mm: resolve virtual_address_range test fail on rhel-9.6

MR: https://gitlab.com/redhat/centos-stream/src/kernel/centos-stream-9/-/merge_requests/6781

JIRA: https://issues.redhat.com/browse/RHEL-88165

Tested: by me, using RHEL-9.6 s390x and aarch64 arches.

This is a bunch of backports to resolve virtual_address_range test fail on rhel9:

```
3bd6137 selftests/mm: virtual_address_range: avoid reading from VM_IO mappings
3c479b5 selftests/mm: vm_util: split up /proc/self/smaps parsing
391e869 mm: selftest to verify zero-filled pages are mapped to zeropage
b2a79f6 selftests/mm: virtual_address_range: unmap chunks after validation
a005145 selftests/mm: virtual_address_range: mmap() without PROT_WRITE
e847f8c selftest/mm: fix typo in virtual_address_range
86483f8 selftests: add ksft_exit_fail_perror()
```

Considering the __get_smap_entry is called by check_vmflag_io() and new ksft_exit_fail_perror() is needed by mark_range(), we have to additionally backport a few more commits (3c479b5, 391e869, 86483f8) to resolve the compiling error on RHEL9.

Conflicts:
- 86483f8: Minor merge conflict of ksft_exit_fail_perror(), no functional changes.
- 3bd6137: Minor merge conflict of check_vmflag_io(), no functional changes.
- 391e869: Dropped updates to split_huge_page_test.c (split_pmd_zero_pages() not needed).

Omitted-fix: 136c5b4 ("selftests/mm: use selftests framework to print test result")

Signed-off-by: Li Wang <liwang@redhat.com>

Approved-by: Rafael Aquini <raquini@redhat.com>
Approved-by: Waiman Long <longman@redhat.com>
Approved-by: CKI KWF Bot <cki-ci-bot+kwf-gitlab-com@redhat.com>

Merged-by: Augusto Caringi <acaringi@redhat.com>

Author: caringi

tools/testing/selftests/kselftest.h

@@ -38,6 +38,7 @@
  * the program is aborting before finishing all tests):
  *
  *    ksft_exit_fail_msg(fmt, ...);
+ *    ksft_exit_fail_perror(msg);
  *
  */
 #ifndef __KSELFTEST_H
@@ -302,6 +303,19 @@ static inline __printf(1, 2) int ksft_exit_fail_msg(const char *msg, ...)
 	exit(KSFT_FAIL);
 }
 
+static inline void ksft_exit_fail_perror(const char *msg)
+{
+#ifndef NOLIBC
+	ksft_exit_fail_msg("%s: %s (%d)\n", msg, strerror(errno), errno);
+#else
+	/*
+	 * nolibc doesn't provide strerror() and it seems
+	 * inappropriate to add one, just print the errno.
+	 */
+	ksft_exit_fail_msg("%s: %d)\n", msg, errno);
+#endif
+}
+
 static inline int ksft_exit_xfail(void)
 {
 	ksft_print_cnts();

tools/testing/selftests/mm/config

@@ -6,3 +6,4 @@ CONFIG_TEST_HMM=m
 CONFIG_GUP_TEST=y
 CONFIG_TRANSPARENT_HUGEPAGE=y
 CONFIG_MEM_SOFT_DIRTY=y
+CONFIG_ANON_VMA_NAME=y

tools/testing/selftests/mm/virtual_address_range.c

@@ -10,10 +10,12 @@
 #include <string.h>
 #include <unistd.h>
 #include <errno.h>
+#include <sys/prctl.h>
 #include <sys/mman.h>
 #include <sys/time.h>
 #include <fcntl.h>
 
+#include "vm_util.h"
 #include "../kselftest.h"
 
 /*
@@ -64,7 +66,7 @@
 #define NR_CHUNKS_HIGH  NR_CHUNKS_384TB
 #endif
 
-static char *hind_addr(void)
+static char *hint_addr(void)
 {
 	int bits = HIGH_ADDR_SHIFT + rand() % (63 - HIGH_ADDR_SHIFT);
 
@@ -82,6 +84,24 @@ static void validate_addr(char *ptr, int high_addr)
 		ksft_exit_fail_msg("Bad address %lx\n", addr);
 }
 
+static void mark_range(char *ptr, size_t size)
+{
+	if (prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, ptr, size, "virtual_address_range") == -1) {
+		if (errno == EINVAL) {
+			/* Depends on CONFIG_ANON_VMA_NAME */
+			ksft_test_result_skip("prctl(PR_SET_VMA_ANON_NAME) not supported\n");
+			ksft_finished();
+		} else {
+			ksft_exit_fail_perror("prctl(PR_SET_VMA_ANON_NAME) failed\n");
+		}
+	}
+}
+
+static int is_marked_vma(const char *vma_name)
+{
+	return vma_name && !strcmp(vma_name, "[anon:virtual_address_range]\n");
+}
+
 static int validate_lower_address_hint(void)
 {
 	char *ptr;
@@ -116,12 +136,17 @@ static int validate_complete_va_space(void)
 
 	prev_end_addr = 0;
 	while (fgets(line, sizeof(line), file)) {
+		const char *vma_name = NULL;
+		int vma_name_start = 0;
 		unsigned long hop;
 
-		if (sscanf(line, "%lx-%lx %s[rwxp-]",
-			   &start_addr, &end_addr, prot) != 3)
+		if (sscanf(line, "%lx-%lx %4s %*s %*s %*s %n",
+			   &start_addr, &end_addr, prot, &vma_name_start) != 3)
 			ksft_exit_fail_msg("cannot parse /proc/self/maps\n");
 
+		if (vma_name_start)
+			vma_name = line + vma_name_start;
+
 		/* end of userspace mappings; ignore vsyscall mapping */
 		if (start_addr & (1UL << 63))
 			return 0;
@@ -135,6 +160,9 @@ static int validate_complete_va_space(void)
 		if (prot[0] != 'r')
 			continue;
 
+		if (check_vmflag_io((void *)start_addr))
+			continue;
+
 		/*
 		 * Confirm whether MAP_CHUNK_SIZE chunk can be found or not.
 		 * If write succeeds, no need to check MAP_CHUNK_SIZE - 1
@@ -149,6 +177,9 @@ static int validate_complete_va_space(void)
 				return 1;
 			lseek(fd, 0, SEEK_SET);
 
+			if (is_marked_vma(vma_name))
+				munmap((char *)(start_addr + hop), MAP_CHUNK_SIZE);
+
 			hop += MAP_CHUNK_SIZE;
 		}
 	}
@@ -166,7 +197,7 @@ int main(int argc, char *argv[])
 	ksft_set_plan(1);
 
 	for (i = 0; i < NR_CHUNKS_LOW; i++) {
-		ptr[i] = mmap(NULL, MAP_CHUNK_SIZE, PROT_READ | PROT_WRITE,
+		ptr[i] = mmap(NULL, MAP_CHUNK_SIZE, PROT_READ,
 			      MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
 
 		if (ptr[i] == MAP_FAILED) {
@@ -175,6 +206,7 @@ int main(int argc, char *argv[])
 			break;
 		}
 
+		mark_range(ptr[i], MAP_CHUNK_SIZE);
 		validate_addr(ptr[i], 0);
 	}
 	lchunks = i;
@@ -185,13 +217,14 @@ int main(int argc, char *argv[])
 	}
 
 	for (i = 0; i < NR_CHUNKS_HIGH; i++) {
-		hint = hind_addr();
-		hptr[i] = mmap(hint, MAP_CHUNK_SIZE, PROT_READ | PROT_WRITE,
+		hint = hint_addr();
+		hptr[i] = mmap(hint, MAP_CHUNK_SIZE, PROT_READ,
 			       MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
 
 		if (hptr[i] == MAP_FAILED)
 			break;
 
+		mark_range(ptr[i], MAP_CHUNK_SIZE);
 		validate_addr(hptr[i], 1);
 	}
 	hchunks = i;

tools/testing/selftests/mm/vm_util.c

@@ -2,6 +2,7 @@
 #include <string.h>
 #include <fcntl.h>
 #include <dirent.h>
+#include <inttypes.h>
 #include <sys/ioctl.h>
 #include <linux/userfaultfd.h>
 #include <sys/syscall.h>
@@ -11,6 +12,7 @@
 
 #define PMD_SIZE_FILE_PATH "/sys/kernel/mm/transparent_hugepage/hpage_pmd_size"
 #define SMAP_FILE_PATH "/proc/self/smaps"
+#define STATUS_FILE_PATH "/proc/self/status"
 #define MAX_LINE_LENGTH 500
 
 unsigned int __page_size;
@@ -97,13 +99,32 @@ uint64_t read_pmd_pagesize(void)
 	return strtoul(buf, NULL, 10);
 }
 
-bool __check_huge(void *addr, char *pattern, int nr_hpages,
-		  uint64_t hpage_size)
+unsigned long rss_anon(void)
 {
-	uint64_t thp = -1;
-	int ret;
+	unsigned long rss_anon = 0;
 	FILE *fp;
 	char buffer[MAX_LINE_LENGTH];
+
+	fp = fopen(STATUS_FILE_PATH, "r");
+	if (!fp)
+		ksft_exit_fail_msg("%s: Failed to open file %s\n", __func__, STATUS_FILE_PATH);
+
+	if (!check_for_pattern(fp, "RssAnon:", buffer, sizeof(buffer)))
+		goto err_out;
+
+	if (sscanf(buffer, "RssAnon:%10lu kB", &rss_anon) != 1)
+		ksft_exit_fail_msg("Reading status error\n");
+
+err_out:
+	fclose(fp);
+	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-",
@@ -115,23 +136,40 @@ bool __check_huge(void *addr, char *pattern, int nr_hpages,
 	if (!fp)
 		ksft_exit_fail_msg("%s: Failed to open file %s\n", __func__, SMAP_FILE_PATH);
 
-	if (!check_for_pattern(fp, addr_pattern, buffer, sizeof(buffer)))
+	if (!check_for_pattern(fp, addr_pattern, buf, len))
 		goto err_out;
 
-	/*
-	 * Fetch the pattern in the same block and check the number of
-	 * hugepages.
-	 */
-	if (!check_for_pattern(fp, pattern, buffer, sizeof(buffer)))
+	/* Fetch the pattern in the same block */
+	if (!check_for_pattern(fp, pattern, buf, len))
 		goto err_out;
 
-	snprintf(addr_pattern, MAX_LINE_LENGTH, "%s%%9ld kB", pattern);
+	/* Trim trailing newline */
+	entry = strchr(buf, '\n');
+	if (entry)
+		*entry = '\0';
 
-	if (sscanf(buffer, addr_pattern, &thp) != 1)
-		ksft_exit_fail_msg("Reading smap error\n");
+	entry = buf + strlen(pattern);
 
 err_out:
 	fclose(fp);
+	return entry;
+}
+
+bool __check_huge(void *addr, char *pattern, int nr_hpages,
+		  uint64_t hpage_size)
+{
+	char buffer[MAX_LINE_LENGTH];
+	uint64_t thp = -1;
+	char *entry;
+
+	entry = __get_smap_entry(addr, pattern, buffer, sizeof(buffer));
+	if (!entry)
+		goto err_out;
+
+	if (sscanf(entry, "%9" SCNu64 " kB", &thp) != 1)
+		ksft_exit_fail_msg("Reading smap error\n");
+
+err_out:
 	return thp == (nr_hpages * (hpage_size >> 10));
 }
 
@@ -218,6 +256,30 @@ unsigned long get_free_hugepages(void)
 	return fhp;
 }
 
+bool check_vmflag_io(void *addr)
+{
+	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("io") && !memcmp(flags, "io", flaglen))
+			return true;
+
+		flags += flaglen;
+	}
+}
+
 int detect_hugetlb_page_sizes(size_t sizes[], int max)
 {
 	DIR *dir = opendir("/sys/kernel/mm/hugepages/");

tools/testing/selftests/mm/vm_util.h

@@ -39,6 +39,7 @@ unsigned long pagemap_get_pfn(int fd, char *start);
 void clear_softdirty(void);
 bool check_for_pattern(FILE *fp, const char *pattern, char *buf, size_t len);
 uint64_t read_pmd_pagesize(void);
+unsigned long rss_anon(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);
@@ -52,6 +53,7 @@ int uffd_register(int uffd, void *addr, uint64_t len,
 int uffd_unregister(int uffd, void *addr, uint64_t len);
 int uffd_register_with_ioctls(int uffd, void *addr, uint64_t len,
 			      bool miss, bool wp, bool minor, uint64_t *ioctls);
+bool check_vmflag_io(void *addr);
 
 /*
  * On ppc64 this will only work with radix 2M hugepage size