Merge tag 'nolibc.2023.06.22a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu

Pull nolibc updates from Paul McKenney:

 - Add stackprotector support

 - Fix RISC-V load-store instruction syntax to support 32-bit binaries,
   plus fixes for generic 32-bit support

 - Fix use of s390 sys_fork()

 - Add my_syscall6() for ARM

 - Support different platforms having different errno definitions

 - Fix ppoll/ppoll_time64 arguments (add the fifth argument)

 - Force use of little endian on MIPS

 - Improved testing, for example, better handling of different compilers
   and compiler versions, comparing nolibc behavior to that of libc, and
   additional test cases

 - Improve syntax and header ordering

 - Use existing <linux/reboot.h> instead of redefining constants

 - Add syscall()

* tag 'nolibc.2023.06.22a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: (53 commits)
  selftests/nolibc: make sure gcc always use little endian on MIPS
  selftests/nolibc: also count skipped and failed tests in output
  selftests/nolibc: add new gettimeofday test cases
  selftests/nolibc: remove gettimeofday_bad1/2 completely
  selftests/nolibc: support two errnos with EXPECT_SYSER2()
  tools/nolibc: open: fix up compile warning for arm
  tools/nolibc: arm: add missing my_syscall6
  selftests/nolibc: use INT_MAX instead of __INT_MAX__
  selftests/nolibc: not include limits.h for nolibc
  selftests/nolibc: fix up compile warning with glibc on x86_64
  selftests/nolibc: allow specify extra arguments for qemu
  selftests/nolibc: remove test gettimeofday_null
  tools/nolibc: ensure fast64 integer types have 64 bits
  selftests/nolibc: test_fork: fix up duplicated print
  tools/nolibc: ppoll/ppoll_time64: add a missing argument
  selftests/nolibc: remove the duplicated gettimeofday_bad2
  selftests/nolibc: print name instead of number for EOVERFLOW
  tools/nolibc: support nanoseconds in stat()
  selftests/nolibc: prevent coredumps during test execution
  tools/nolibc: add support for prctl()
  ...

3 files changed, 218 insertions, 49 deletions

diff --git a/tools/testing/selftests/nolibc/.gitignore b/tools/testing/selftests/nolibc/.gitignore
index 4696df589d68..52f613cdad54 100644
--- a/tools/testing/selftests/nolibc/.gitignore
+++ b/tools/testing/selftests/nolibc/.gitignore
@@ -1,4 +1,5 @@
 /initramfs/
+/libc-test
 /nolibc-test
 /run.out
 /sysroot/
diff --git a/tools/testing/selftests/nolibc/Makefile b/tools/testing/selftests/nolibc/Makefile
index bbce57420465..1b7b3c82f8ad 100644
--- a/tools/testing/selftests/nolibc/Makefile
+++ b/tools/testing/selftests/nolibc/Makefile
@@ -64,7 +64,7 @@ QEMU_ARGS_mips       = -M malta -append "panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_riscv      = -M virt -append "console=ttyS0 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_s390       = -M s390-ccw-virtio -m 1G -append "console=ttyS0 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_loongarch  = -M virt -append "console=ttyS0,115200 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
-QEMU_ARGS            = $(QEMU_ARGS_$(ARCH))
+QEMU_ARGS            = $(QEMU_ARGS_$(ARCH)) $(QEMU_ARGS_EXTRA)
 
 # OUTPUT is only set when run from the main makefile, otherwise
 # it defaults to this nolibc directory.
@@ -76,16 +76,12 @@ else
 Q=@
 endif
 
-CFLAGS_STACKPROTECTOR = -DNOLIBC_STACKPROTECTOR \
-			$(call cc-option,-mstack-protector-guard=global) \
-			$(call cc-option,-fstack-protector-all)
-CFLAGS_STKP_i386 = $(CFLAGS_STACKPROTECTOR)
-CFLAGS_STKP_x86_64 = $(CFLAGS_STACKPROTECTOR)
-CFLAGS_STKP_x86 = $(CFLAGS_STACKPROTECTOR)
 CFLAGS_s390 = -m64
-CFLAGS  ?= -Os -fno-ident -fno-asynchronous-unwind-tables \
+CFLAGS_mips = -EL
+CFLAGS_STACKPROTECTOR ?= $(call cc-option,-mstack-protector-guard=global $(call cc-option,-fstack-protector-all))
+CFLAGS  ?= -Os -fno-ident -fno-asynchronous-unwind-tables -std=c89 \
 		$(call cc-option,-fno-stack-protector) \
-		$(CFLAGS_STKP_$(ARCH)) $(CFLAGS_$(ARCH))
+		$(CFLAGS_$(ARCH)) $(CFLAGS_STACKPROTECTOR)
 LDFLAGS := -s
 
 help:
@@ -94,6 +90,7 @@ help:
 	@echo "  help         this help"
 	@echo "  sysroot      create the nolibc sysroot here (uses \$$ARCH)"
 	@echo "  nolibc-test  build the executable (uses \$$CC and \$$CROSS_COMPILE)"
+	@echo "  libc-test    build an executable using the compiler's default libc instead"
 	@echo "  run-user     runs the executable under QEMU (uses \$$ARCH, \$$TEST)"
 	@echo "  initramfs    prepare the initramfs with nolibc-test"
 	@echo "  defconfig    create a fresh new default config (uses \$$ARCH)"
@@ -128,10 +125,16 @@ nolibc-test: nolibc-test.c sysroot/$(ARCH)/include
 	$(QUIET_CC)$(CC) $(CFLAGS) $(LDFLAGS) -o $@ \
 	  -nostdlib -static -Isysroot/$(ARCH)/include $< -lgcc
 
+libc-test: nolibc-test.c
+	$(QUIET_CC)$(CC) -o $@ $<
+
 # qemu user-land test
 run-user: nolibc-test
 	$(Q)qemu-$(QEMU_ARCH) ./nolibc-test > "$(CURDIR)/run.out" || :
-	$(Q)grep -w FAIL "$(CURDIR)/run.out" && echo "See all results in $(CURDIR)/run.out" || echo "$$(grep -c ^[0-9].*OK $(CURDIR)/run.out) test(s) passed."
+	$(Q)awk '/\[OK\][\r]*$$/{p++} /\[FAIL\][\r]*$$/{f++} /\[SKIPPED\][\r]*$$/{s++} \
+	         END{ printf("%d test(s) passed, %d skipped, %d failed.", p, s, f); \
+	         if (s+f > 0) printf(" See all results in %s\n", ARGV[1]); else print; }' \
+	         $(CURDIR)/run.out
 
 initramfs: nolibc-test
 	$(QUIET_MKDIR)mkdir -p initramfs
@@ -147,18 +150,26 @@ kernel: initramfs
 # run the tests after building the kernel
 run: kernel
 	$(Q)qemu-system-$(QEMU_ARCH) -display none -no-reboot -kernel "$(srctree)/$(IMAGE)" -serial stdio $(QEMU_ARGS) > "$(CURDIR)/run.out"
-	$(Q)grep -w FAIL "$(CURDIR)/run.out" && echo "See all results in $(CURDIR)/run.out" || echo "$$(grep -c ^[0-9].*OK $(CURDIR)/run.out) test(s) passed."
+	$(Q)awk '/\[OK\][\r]*$$/{p++} /\[FAIL\][\r]*$$/{f++} /\[SKIPPED\][\r]*$$/{s++} \
+	         END{ printf("%d test(s) passed, %d skipped, %d failed.", p, s, f); \
+	         if (s+f > 0) printf(" See all results in %s\n", ARGV[1]); else print; }' \
+	         $(CURDIR)/run.out
 
 # re-run the tests from an existing kernel
 rerun:
 	$(Q)qemu-system-$(QEMU_ARCH) -display none -no-reboot -kernel "$(srctree)/$(IMAGE)" -serial stdio $(QEMU_ARGS) > "$(CURDIR)/run.out"
-	$(Q)grep -w FAIL "$(CURDIR)/run.out" && echo "See all results in $(CURDIR)/run.out" || echo "$$(grep -c ^[0-9].*OK $(CURDIR)/run.out) test(s) passed."
+	$(Q)awk '/\[OK\][\r]*$$/{p++} /\[FAIL\][\r]*$$/{f++} /\[SKIPPED\][\r]*$$/{s++} \
+	         END{ printf("%d test(s) passed, %d skipped, %d failed.", p, s, f); \
+	         if (s+f > 0) printf(" See all results in %s\n", ARGV[1]); else print; }' \
+	         $(CURDIR)/run.out
 
 clean:
 	$(call QUIET_CLEAN, sysroot)
 	$(Q)rm -rf sysroot
 	$(call QUIET_CLEAN, nolibc-test)
 	$(Q)rm -f nolibc-test
+	$(call QUIET_CLEAN, libc-test)
+	$(Q)rm -f libc-test
 	$(call QUIET_CLEAN, initramfs)
 	$(Q)rm -rf initramfs
 	$(call QUIET_CLEAN, run.out)
diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c
index 21bacc928bf7..486334981e60 100644
--- a/tools/testing/selftests/nolibc/nolibc-test.c
+++ b/tools/testing/selftests/nolibc/nolibc-test.c
@@ -1,10 +1,7 @@
-// SPDX-License-Identifier: GPL-2.0
+/* SPDX-License-Identifier: GPL-2.0 */
 
 #define _GNU_SOURCE
 
-/* platform-specific include files coming from the compiler */
-#include <limits.h>
-
 /* libc-specific include files
  * The program may be built in 3 ways:
  *   $(CC) -nostdlib -include /path/to/nolibc.h => NOLIBC already defined
@@ -20,7 +17,9 @@
 #include <linux/reboot.h>
 #include <sys/io.h>
 #include <sys/ioctl.h>
+#include <sys/mman.h>
 #include <sys/mount.h>
+#include <sys/prctl.h>
 #include <sys/reboot.h>
 #include <sys/stat.h>
 #include <sys/syscall.h>
@@ -34,7 +33,10 @@
 #include <sched.h>
 #include <signal.h>
 #include <stdarg.h>
+#include <stddef.h>
+#include <stdint.h>
 #include <unistd.h>
+#include <limits.h>
 #endif
 #endif
 
@@ -43,8 +45,8 @@ char **environ;
 
 /* definition of a series of tests */
 struct test {
-	const char *name;              // test name
-	int (*func)(int min, int max); // handler
+	const char *name;              /* test name */
+	int (*func)(int min, int max); /* handler */
 };
 
 #ifndef _NOLIBC_STDLIB_H
@@ -103,24 +105,32 @@ const char *errorname(int err)
 	CASE_ERR(EDOM);
 	CASE_ERR(ERANGE);
 	CASE_ERR(ENOSYS);
+	CASE_ERR(EOVERFLOW);
 	default:
 		return itoa(err);
 	}
 }
 
+static void putcharn(char c, size_t n)
+{
+	char buf[64];
+
+	memset(buf, c, n);
+	buf[n] = '\0';
+	fputs(buf, stdout);
+}
+
 static int pad_spc(int llen, int cnt, const char *fmt, ...)
 {
 	va_list args;
-	int len;
 	int ret;
 
-	for (len = 0; len < cnt - llen; len++)
-		putchar(' ');
+	putcharn(' ', cnt - llen);
 
 	va_start(args, fmt);
 	ret = vfprintf(stdout, fmt, args);
 	va_end(args);
-	return ret < 0 ? ret : ret + len;
+	return ret < 0 ? ret : ret + cnt - llen;
 }
 
 /* The tests below are intended to be used by the macroes, which evaluate
@@ -162,7 +172,7 @@ static int expect_eq(uint64_t expr, int llen, uint64_t val)
 {
 	int ret = !(expr == val);
 
-	llen += printf(" = %lld ", expr);
+	llen += printf(" = %lld ", (long long)expr);
 	pad_spc(llen, 64, ret ? "[FAIL]\n" : " [OK]\n");
 	return ret;
 }
@@ -290,18 +300,24 @@ static int expect_sysne(int expr, int llen, int val)
 }
 
 
+#define EXPECT_SYSER2(cond, expr, expret, experr1, experr2)		\
+	do { if (!cond) pad_spc(llen, 64, "[SKIPPED]\n"); else ret += expect_syserr2(expr, expret, experr1, experr2, llen); } while (0)
+
 #define EXPECT_SYSER(cond, expr, expret, experr)			\
-	do { if (!cond) pad_spc(llen, 64, "[SKIPPED]\n"); else ret += expect_syserr(expr, expret, experr, llen); } while (0)
+	EXPECT_SYSER2(cond, expr, expret, experr, 0)
 
-static int expect_syserr(int expr, int expret, int experr, int llen)
+static int expect_syserr2(int expr, int expret, int experr1, int experr2, int llen)
 {
 	int ret = 0;
 	int _errno = errno;
 
 	llen += printf(" = %d %s ", expr, errorname(_errno));
-	if (expr != expret || _errno != experr) {
+	if (expr != expret || (_errno != experr1 && _errno != experr2)) {
 		ret = 1;
-		llen += printf(" != (%d %s) ", expret, errorname(experr));
+		if (experr2 == 0)
+			llen += printf(" != (%d %s) ", expret, errorname(experr1));
+		else
+			llen += printf(" != (%d %s %s) ", expret, errorname(experr1), errorname(experr2));
 		llen += pad_spc(llen, 64, "[FAIL]\n");
 	} else {
 		llen += pad_spc(llen, 64, " [OK]\n");
@@ -471,11 +487,60 @@ static int test_getpagesize(void)
 	return !c;
 }
 
+static int test_fork(void)
+{
+	int status;
+	pid_t pid;
+
+	/* flush the printf buffer to avoid child flush it */
+	fflush(stdout);
+	fflush(stderr);
+
+	pid = fork();
+
+	switch (pid) {
+	case -1:
+		return 1;
+
+	case 0:
+		exit(123);
+
+	default:
+		pid = waitpid(pid, &status, 0);
+
+		return pid == -1 || !WIFEXITED(status) || WEXITSTATUS(status) != 123;
+	}
+}
+
+static int test_stat_timestamps(void)
+{
+	struct stat st;
+
+	if (sizeof(st.st_atim.tv_sec) != sizeof(st.st_atime))
+		return 1;
+
+	if (stat("/proc/self/", &st))
+		return 1;
+
+	if (st.st_atim.tv_sec != st.st_atime || st.st_atim.tv_nsec > 1000000000)
+		return 1;
+
+	if (st.st_mtim.tv_sec != st.st_mtime || st.st_mtim.tv_nsec > 1000000000)
+		return 1;
+
+	if (st.st_ctim.tv_sec != st.st_ctime || st.st_ctim.tv_nsec > 1000000000)
+		return 1;
+
+	return 0;
+}
+
 /* Run syscall tests between IDs <min> and <max>.
  * Return 0 on success, non-zero on failure.
  */
 int run_syscall(int min, int max)
 {
+	struct timeval tv;
+	struct timezone tz;
 	struct stat stat_buf;
 	int euid0;
 	int proc;
@@ -491,7 +556,7 @@ int run_syscall(int min, int max)
 	euid0 = geteuid() == 0;
 
 	for (test = min; test >= 0 && test <= max; test++) {
-		int llen = 0; // line length
+		int llen = 0; /* line length */
 
 		/* avoid leaving empty lines below, this will insert holes into
 		 * test numbers.
@@ -527,14 +592,11 @@ int run_syscall(int min, int max)
 		CASE_TEST(dup3_0);            tmp = dup3(0, 100, 0);  EXPECT_SYSNE(1, tmp, -1); close(tmp); break;
 		CASE_TEST(dup3_m1);           tmp = dup3(-1, 100, 0); EXPECT_SYSER(1, tmp, -1, EBADF); if (tmp != -1) close(tmp); break;
 		CASE_TEST(execve_root);       EXPECT_SYSER(1, execve("/", (char*[]){ [0] = "/", [1] = NULL }, NULL), -1, EACCES); break;
+		CASE_TEST(fork);              EXPECT_SYSZR(1, test_fork()); break;
 		CASE_TEST(getdents64_root);   EXPECT_SYSNE(1, test_getdents64("/"), -1); break;
 		CASE_TEST(getdents64_null);   EXPECT_SYSER(1, test_getdents64("/dev/null"), -1, ENOTDIR); break;
-		CASE_TEST(gettimeofday_null); EXPECT_SYSZR(1, gettimeofday(NULL, NULL)); break;
-#ifdef NOLIBC
-		CASE_TEST(gettimeofday_bad1); EXPECT_SYSER(1, gettimeofday((void *)1, NULL), -1, EFAULT); break;
-		CASE_TEST(gettimeofday_bad2); EXPECT_SYSER(1, gettimeofday(NULL, (void *)1), -1, EFAULT); break;
-		CASE_TEST(gettimeofday_bad2); EXPECT_SYSER(1, gettimeofday(NULL, (void *)1), -1, EFAULT); break;
-#endif
+		CASE_TEST(gettimeofday_tv);   EXPECT_SYSZR(1, gettimeofday(&tv, NULL)); break;
+		CASE_TEST(gettimeofday_tv_tz);EXPECT_SYSZR(1, gettimeofday(&tv, &tz)); break;
 		CASE_TEST(getpagesize);       EXPECT_SYSZR(1, test_getpagesize()); break;
 		CASE_TEST(ioctl_tiocinq);     EXPECT_SYSZR(1, ioctl(0, TIOCINQ, &tmp)); break;
 		CASE_TEST(ioctl_tiocinq);     EXPECT_SYSZR(1, ioctl(0, TIOCINQ, &tmp)); break;
@@ -550,6 +612,7 @@ int run_syscall(int min, int max)
 		CASE_TEST(poll_null);         EXPECT_SYSZR(1, poll(NULL, 0, 0)); break;
 		CASE_TEST(poll_stdout);       EXPECT_SYSNE(1, ({ struct pollfd fds = { 1, POLLOUT, 0}; poll(&fds, 1, 0); }), -1); break;
 		CASE_TEST(poll_fault);        EXPECT_SYSER(1, poll((void *)1, 1, 0), -1, EFAULT); break;
+		CASE_TEST(prctl);             EXPECT_SYSER(1, prctl(PR_SET_NAME, (unsigned long)NULL, 0, 0, 0), -1, EFAULT); break;
 		CASE_TEST(read_badf);         EXPECT_SYSER(1, read(-1, &tmp, 1), -1, EBADF); break;
 		CASE_TEST(sched_yield);       EXPECT_SYSZR(1, sched_yield()); break;
 		CASE_TEST(select_null);       EXPECT_SYSZR(1, ({ struct timeval tv = { 0 }; select(0, NULL, NULL, NULL, &tv); })); break;
@@ -557,6 +620,7 @@ int run_syscall(int min, int max)
 		CASE_TEST(select_fault);      EXPECT_SYSER(1, select(1, (void *)1, NULL, NULL, 0), -1, EFAULT); break;
 		CASE_TEST(stat_blah);         EXPECT_SYSER(1, stat("/proc/self/blah", &stat_buf), -1, ENOENT); break;
 		CASE_TEST(stat_fault);        EXPECT_SYSER(1, stat(NULL, &stat_buf), -1, EFAULT); break;
+		CASE_TEST(stat_timestamps);   EXPECT_SYSZR(1, test_stat_timestamps()); break;
 		CASE_TEST(symlink_root);      EXPECT_SYSER(1, symlink("/", "/"), -1, EEXIST); break;
 		CASE_TEST(unlink_root);       EXPECT_SYSER(1, unlink("/"), -1, EISDIR); break;
 		CASE_TEST(unlink_blah);       EXPECT_SYSER(1, unlink("/proc/self/blah"), -1, ENOENT); break;
@@ -565,6 +629,8 @@ int run_syscall(int min, int max)
 		CASE_TEST(waitpid_child);     EXPECT_SYSER(1, waitpid(getpid(), &tmp, WNOHANG), -1, ECHILD); break;
 		CASE_TEST(write_badf);        EXPECT_SYSER(1, write(-1, &tmp, 1), -1, EBADF); break;
 		CASE_TEST(write_zero);        EXPECT_SYSZR(1, write(1, &tmp, 0)); break;
+		CASE_TEST(syscall_noargs);    EXPECT_SYSEQ(1, syscall(__NR_getpid), getpid()); break;
+		CASE_TEST(syscall_args);      EXPECT_SYSER(1, syscall(__NR_statx, 0, NULL, 0, 0, NULL), -1, EFAULT); break;
 		case __LINE__:
 			return ret; /* must be last */
 		/* note: do not set any defaults so as to permit holes above */
@@ -581,7 +647,7 @@ int run_stdlib(int min, int max)
 	void *p1, *p2;
 
 	for (test = min; test >= 0 && test <= max; test++) {
-		int llen = 0; // line length
+		int llen = 0; /* line length */
 
 		/* avoid leaving empty lines below, this will insert holes into
 		 * test numbers.
@@ -639,9 +705,9 @@ int run_stdlib(int min, int max)
 		CASE_TEST(limit_int_fast32_min);    EXPECT_EQ(1, INT_FAST32_MIN,   (int_fast32_t)    INTPTR_MIN); break;
 		CASE_TEST(limit_int_fast32_max);    EXPECT_EQ(1, INT_FAST32_MAX,   (int_fast32_t)    INTPTR_MAX); break;
 		CASE_TEST(limit_uint_fast32_max);   EXPECT_EQ(1, UINT_FAST32_MAX,  (uint_fast32_t)   UINTPTR_MAX); break;
-		CASE_TEST(limit_int_fast64_min);    EXPECT_EQ(1, INT_FAST64_MIN,   (int_fast64_t)    INTPTR_MIN); break;
-		CASE_TEST(limit_int_fast64_max);    EXPECT_EQ(1, INT_FAST64_MAX,   (int_fast64_t)    INTPTR_MAX); break;
-		CASE_TEST(limit_uint_fast64_max);   EXPECT_EQ(1, UINT_FAST64_MAX,  (uint_fast64_t)   UINTPTR_MAX); break;
+		CASE_TEST(limit_int_fast64_min);    EXPECT_EQ(1, INT_FAST64_MIN,   (int_fast64_t)    INT64_MIN); break;
+		CASE_TEST(limit_int_fast64_max);    EXPECT_EQ(1, INT_FAST64_MAX,   (int_fast64_t)    INT64_MAX); break;
+		CASE_TEST(limit_uint_fast64_max);   EXPECT_EQ(1, UINT_FAST64_MAX,  (uint_fast64_t)   UINT64_MAX); break;
 #if __SIZEOF_LONG__ == 8
 		CASE_TEST(limit_intptr_min);        EXPECT_EQ(1, INTPTR_MIN,       (intptr_t)        0x8000000000000000LL); break;
 		CASE_TEST(limit_intptr_max);        EXPECT_EQ(1, INTPTR_MAX,       (intptr_t)        0x7fffffffffffffffLL); break;
@@ -667,17 +733,98 @@ int run_stdlib(int min, int max)
 	return ret;
 }
 
-#if defined(__clang__)
-__attribute__((optnone))
-#elif defined(__GNUC__)
-__attribute__((optimize("O0")))
-#endif
+#define EXPECT_VFPRINTF(c, expected, fmt, ...)				\
+	ret += expect_vfprintf(llen, c, expected, fmt, ##__VA_ARGS__)
+
+static int expect_vfprintf(int llen, size_t c, const char *expected, const char *fmt, ...)
+{
+	int ret, fd, w, r;
+	char buf[100];
+	FILE *memfile;
+	va_list args;
+
+	fd = memfd_create("vfprintf", 0);
+	if (fd == -1) {
+		pad_spc(llen, 64, "[FAIL]\n");
+		return 1;
+	}
+
+	memfile = fdopen(fd, "w+");
+	if (!memfile) {
+		pad_spc(llen, 64, "[FAIL]\n");
+		return 1;
+	}
+
+	va_start(args, fmt);
+	w = vfprintf(memfile, fmt, args);
+	va_end(args);
+
+	if (w != c) {
+		llen += printf(" written(%d) != %d", w, (int) c);
+		pad_spc(llen, 64, "[FAIL]\n");
+		return 1;
+	}
+
+	fflush(memfile);
+	lseek(fd, 0, SEEK_SET);
+
+	r = read(fd, buf, sizeof(buf) - 1);
+	buf[r] = '\0';
+
+	fclose(memfile);
+
+	if (r != w) {
+		llen += printf(" written(%d) != read(%d)", w, r);
+		pad_spc(llen, 64, "[FAIL]\n");
+		return 1;
+	}
+
+	llen += printf(" \"%s\" = \"%s\"", expected, buf);
+	ret = strncmp(expected, buf, c);
+
+	pad_spc(llen, 64, ret ? "[FAIL]\n" : " [OK]\n");
+	return ret;
+}
+
+static int run_vfprintf(int min, int max)
+{
+	int test;
+	int tmp;
+	int ret = 0;
+	void *p1, *p2;
+
+	for (test = min; test >= 0 && test <= max; test++) {
+		int llen = 0; /* line length */
+
+		/* avoid leaving empty lines below, this will insert holes into
+		 * test numbers.
+		 */
+		switch (test + __LINE__ + 1) {
+		CASE_TEST(empty);        EXPECT_VFPRINTF(0, "", ""); break;
+		CASE_TEST(simple);       EXPECT_VFPRINTF(3, "foo", "foo"); break;
+		CASE_TEST(string);       EXPECT_VFPRINTF(3, "foo", "%s", "foo"); break;
+		CASE_TEST(number);       EXPECT_VFPRINTF(4, "1234", "%d", 1234); break;
+		CASE_TEST(negnumber);    EXPECT_VFPRINTF(5, "-1234", "%d", -1234); break;
+		CASE_TEST(unsigned);     EXPECT_VFPRINTF(5, "12345", "%u", 12345); break;
+		CASE_TEST(char);         EXPECT_VFPRINTF(1, "c", "%c", 'c'); break;
+		CASE_TEST(hex);          EXPECT_VFPRINTF(1, "f", "%x", 0xf); break;
+		CASE_TEST(pointer);      EXPECT_VFPRINTF(3, "0x1", "%p", (void *) 0x1); break;
+		case __LINE__:
+			return ret; /* must be last */
+		/* note: do not set any defaults so as to permit holes above */
+		}
+	}
+	return ret;
+}
+
 static int smash_stack(void)
 {
 	char buf[100];
+	volatile char *ptr = buf;
+	size_t i;
 
-	for (size_t i = 0; i < 200; i++)
-		buf[i] = 'P';
+	for (i = 0; i < 200; i++)
+		ptr[i] = 'P';
 
 	return 1;
 }
@@ -689,12 +836,20 @@ static int run_protection(int min, int max)
 
 	llen += printf("0 -fstackprotector ");
 
-#if !defined(NOLIBC_STACKPROTECTOR)
+#if !defined(_NOLIBC_STACKPROTECTOR)
 	llen += printf("not supported");
 	pad_spc(llen, 64, "[SKIPPED]\n");
 	return 0;
 #endif
 
+#if defined(_NOLIBC_STACKPROTECTOR)
+	if (!__stack_chk_guard) {
+		llen += printf("__stack_chk_guard not initialized");
+		pad_spc(llen, 64, "[FAIL]\n");
+		return 1;
+	}
+#endif
+
 	pid = -1;
 	pid = fork();
 
@@ -708,6 +863,7 @@ static int run_protection(int min, int max)
 		close(STDOUT_FILENO);
 		close(STDERR_FILENO);
 
+		prctl(PR_SET_DUMPABLE, 0, 0, 0, 0);
 		smash_stack();
 		return 1;
 
@@ -778,6 +934,7 @@ static const struct test test_names[] = {
 	/* add new tests here */
 	{ .name = "syscall",    .func = run_syscall    },
 	{ .name = "stdlib",     .func = run_stdlib     },
+	{ .name = "vfprintf",   .func = run_vfprintf   },
 	{ .name = "protection", .func = run_protection },
 	{ 0 }
 };
@@ -785,7 +942,7 @@ static const struct test test_names[] = {
 int main(int argc, char **argv, char **envp)
 {
 	int min = 0;
-	int max = __INT_MAX__;
+	int max = INT_MAX;
 	int ret = 0;
 	int err;
 	int idx;
@@ -833,7 +990,7 @@ int main(int argc, char **argv, char **envp)
 				 * here, which defaults to the full range.
 				 */
 				do {
-					min = 0; max = __INT_MAX__;
+					min = 0; max = INT_MAX;
 					value = colon;
 					if (value && *value) {
 						colon = strchr(value, ':');
@@ -899,7 +1056,7 @@ int main(int argc, char **argv, char **envp)
 #else
 		else if (ioperm(0x501, 1, 1) == 0)
 #endif
-			asm volatile ("outb %%al, %%dx" :: "d"(0x501), "a"(0));
+			__asm__ volatile ("outb %%al, %%dx" :: "d"(0x501), "a"(0));
 		/* if it does nothing, fall back to the regular panic */
 #endif
 	}