scftorture: Count single_rpc offline failures in statistics outputgrafted

scf_torture_stats_print() aggregates each invoker thread's counters
into a local scf_statistics structure before printing, but the
n_single_rpc_ofl field is missing from the aggregation loop.  As a
result, the "single_rpc_ofl" value printed in the statistics line is
always zero, even when smp_call_function_single() invocations for the
RPC test have failed due to offline CPUs and been counted by the
invoker threads.

Add the missing accumulation so that the printed value reflects the
actual counts.

Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

8 files changed, 336 insertions, 0 deletions

diff --git a/samples/check-exec/.gitignore b/samples/check-exec/.gitignore
new file mode 100644
index 000000000..cd759a19d
--- /dev/null
+++ b/samples/check-exec/.gitignore
@@ -0,0 +1,2 @@
+/inc
+/set-exec
diff --git a/samples/check-exec/Makefile b/samples/check-exec/Makefile
new file mode 100644
index 000000000..c4f08ad0f
--- /dev/null
+++ b/samples/check-exec/Makefile
@@ -0,0 +1,15 @@
+# SPDX-License-Identifier: BSD-3-Clause
+
+userprogs-always-y := \
+	inc \
+	set-exec
+
+userccflags += -I usr/include
+
+.PHONY: all clean
+
+all:
+	$(MAKE) -C ../.. samples/check-exec/
+
+clean:
+	$(MAKE) -C ../.. M=samples/check-exec/ clean
diff --git a/samples/check-exec/inc.c b/samples/check-exec/inc.c
new file mode 100644
index 000000000..7f6ef06a2
--- /dev/null
+++ b/samples/check-exec/inc.c
@@ -0,0 +1,212 @@
+// SPDX-License-Identifier: BSD-3-Clause
+/*
+ * Very simple script interpreter that can evaluate two different commands (one
+ * per line):
+ * - "?" to initialize a counter from user's input;
+ * - "+" to increment the counter (which is set to 0 by default).
+ *
+ * See tools/testing/selftests/exec/check-exec-tests.sh and
+ * Documentation/userspace-api/check_exec.rst
+ *
+ * Copyright © 2024 Microsoft Corporation
+ */
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <linux/fcntl.h>
+#include <linux/prctl.h>
+#include <linux/securebits.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/prctl.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+static int sys_execveat(int dirfd, const char *pathname, char *const argv[],
+			char *const envp[], int flags)
+{
+	return syscall(__NR_execveat, dirfd, pathname, argv, envp, flags);
+}
+
+/* Returns 1 on error, 0 otherwise. */
+static int interpret_buffer(char *buffer, size_t buffer_size)
+{
+	char *line, *saveptr = NULL;
+	long long number = 0;
+
+	/* Each command is the first character of a line. */
+	saveptr = NULL;
+	line = strtok_r(buffer, "\n", &saveptr);
+	while (line) {
+		if (*line != '#' && strlen(line) != 1) {
+			fprintf(stderr, "# ERROR: Unknown string\n");
+			return 1;
+		}
+		switch (*line) {
+		case '#':
+			/* Skips shebang and comments. */
+			break;
+		case '+':
+			/* Increments and prints the number. */
+			number++;
+			printf("%lld\n", number);
+			break;
+		case '?':
+			/* Reads integer from stdin. */
+			fprintf(stderr, "> Enter new number: \n");
+			if (scanf("%lld", &number) != 1) {
+				fprintf(stderr,
+					"# WARNING: Failed to read number from stdin\n");
+			}
+			break;
+		default:
+			fprintf(stderr, "# ERROR: Unknown character '%c'\n",
+				*line);
+			return 1;
+		}
+		line = strtok_r(NULL, "\n", &saveptr);
+	}
+	return 0;
+}
+
+/* Returns 1 on error, 0 otherwise. */
+static int interpret_stream(FILE *script, char *const script_name,
+			    char *const *const envp, const bool restrict_stream)
+{
+	int err;
+	char *const script_argv[] = { script_name, NULL };
+	char buf[128] = {};
+	size_t buf_size = sizeof(buf);
+
+	/*
+	 * We pass a valid argv and envp to the kernel to emulate a native
+	 * script execution.  We must use the script file descriptor instead of
+	 * the script path name to avoid race conditions.
+	 */
+	err = sys_execveat(fileno(script), "", script_argv, envp,
+			   AT_EMPTY_PATH | AT_EXECVE_CHECK);
+	if (err && restrict_stream) {
+		perror("ERROR: Script execution check");
+		return 1;
+	}
+
+	/* Reads script. */
+	buf_size = fread(buf, 1, buf_size - 1, script);
+	return interpret_buffer(buf, buf_size);
+}
+
+static void print_usage(const char *argv0)
+{
+	fprintf(stderr, "usage: %s <script.inc> | -i | -c <command>\n\n",
+		argv0);
+	fprintf(stderr, "Example:\n");
+	fprintf(stderr, "  ./set-exec -fi -- ./inc -i < script-exec.inc\n");
+}
+
+int main(const int argc, char *const argv[], char *const *const envp)
+{
+	int opt;
+	char *cmd = NULL;
+	char *script_name = NULL;
+	bool interpret_stdin = false;
+	FILE *script_file = NULL;
+	int secbits;
+	bool deny_interactive, restrict_file;
+	size_t arg_nb;
+
+	secbits = prctl(PR_GET_SECUREBITS);
+	if (secbits == -1) {
+		/*
+		 * This should never happen, except with a buggy seccomp
+		 * filter.
+		 */
+		perror("ERROR: Failed to get securebits");
+		return 1;
+	}
+
+	deny_interactive = !!(secbits & SECBIT_EXEC_DENY_INTERACTIVE);
+	restrict_file = !!(secbits & SECBIT_EXEC_RESTRICT_FILE);
+
+	while ((opt = getopt(argc, argv, "c:i")) != -1) {
+		switch (opt) {
+		case 'c':
+			if (cmd) {
+				fprintf(stderr, "ERROR: Command already set");
+				return 1;
+			}
+			cmd = optarg;
+			break;
+		case 'i':
+			interpret_stdin = true;
+			break;
+		default:
+			print_usage(argv[0]);
+			return 1;
+		}
+	}
+
+	/* Checks that only one argument is used, or read stdin. */
+	arg_nb = !!cmd + !!interpret_stdin;
+	if (arg_nb == 0 && argc == 2) {
+		script_name = argv[1];
+	} else if (arg_nb != 1) {
+		print_usage(argv[0]);
+		return 1;
+	}
+
+	if (cmd) {
+		/*
+		 * Other kind of interactive interpretations should be denied
+		 * as well (e.g. CLI arguments passing script snippets,
+		 * environment variables interpreted as script).  However, any
+		 * way to pass script files should only be restricted according
+		 * to restrict_file.
+		 */
+		if (deny_interactive) {
+			fprintf(stderr,
+				"ERROR: Interactive interpretation denied.\n");
+			return 1;
+		}
+
+		return interpret_buffer(cmd, strlen(cmd));
+	}
+
+	if (interpret_stdin && !script_name) {
+		script_file = stdin;
+		/*
+		 * As for any execve(2) call, this path may be logged by the
+		 * kernel.
+		 */
+		script_name = "/proc/self/fd/0";
+		/*
+		 * When stdin is used, it can point to a regular file or a
+		 * pipe.  Restrict stdin execution according to
+		 * SECBIT_EXEC_DENY_INTERACTIVE but always allow executable
+		 * files (which are not considered as interactive inputs).
+		 */
+		return interpret_stream(script_file, script_name, envp,
+					deny_interactive);
+	} else if (script_name && !interpret_stdin) {
+		/*
+		 * In this sample, we don't pass any argument to scripts, but
+		 * otherwise we would have to forge an argv with such
+		 * arguments.
+		 */
+		script_file = fopen(script_name, "r");
+		if (!script_file) {
+			perror("ERROR: Failed to open script");
+			return 1;
+		}
+		/*
+		 * Restricts file execution according to
+		 * SECBIT_EXEC_RESTRICT_FILE.
+		 */
+		return interpret_stream(script_file, script_name, envp,
+					restrict_file);
+	}
+
+	print_usage(argv[0]);
+	return 1;
+}
diff --git a/samples/check-exec/run-script-ask.sh b/samples/check-exec/run-script-ask.sh
new file mode 100755
index 000000000..8ef0fdc37
--- /dev/null
+++ b/samples/check-exec/run-script-ask.sh
@@ -0,0 +1,9 @@
+#!/usr/bin/env sh
+# SPDX-License-Identifier: BSD-3-Clause
+
+DIR="$(dirname -- "$0")"
+
+PATH="${PATH}:${DIR}"
+
+set -x
+"${DIR}/script-ask.inc"
diff --git a/samples/check-exec/script-ask.inc b/samples/check-exec/script-ask.inc
new file mode 100755
index 000000000..720a8e649
--- /dev/null
+++ b/samples/check-exec/script-ask.inc
@@ -0,0 +1,5 @@
+#!/usr/bin/env inc
+# SPDX-License-Identifier: BSD-3-Clause
+
+?
++
diff --git a/samples/check-exec/script-exec.inc b/samples/check-exec/script-exec.inc
new file mode 100755
index 000000000..3245cb9d8
--- /dev/null
+++ b/samples/check-exec/script-exec.inc
@@ -0,0 +1,4 @@
+#!/usr/bin/env inc
+# SPDX-License-Identifier: BSD-3-Clause
+
++
diff --git a/samples/check-exec/script-noexec.inc b/samples/check-exec/script-noexec.inc
new file mode 100644
index 000000000..3245cb9d8
--- /dev/null
+++ b/samples/check-exec/script-noexec.inc
@@ -0,0 +1,4 @@
+#!/usr/bin/env inc
+# SPDX-License-Identifier: BSD-3-Clause
+
++
diff --git a/samples/check-exec/set-exec.c b/samples/check-exec/set-exec.c
new file mode 100644
index 000000000..ba86a60a2
--- /dev/null
+++ b/samples/check-exec/set-exec.c
@@ -0,0 +1,85 @@
+// SPDX-License-Identifier: BSD-3-Clause
+/*
+ * Simple tool to set SECBIT_EXEC_RESTRICT_FILE, SECBIT_EXEC_DENY_INTERACTIVE,
+ * before executing a command.
+ *
+ * Copyright © 2024 Microsoft Corporation
+ */
+
+#define _GNU_SOURCE
+#define __SANE_USERSPACE_TYPES__
+#include <errno.h>
+#include <linux/prctl.h>
+#include <linux/securebits.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/prctl.h>
+#include <unistd.h>
+
+static void print_usage(const char *argv0)
+{
+	fprintf(stderr, "usage: %s -f|-i -- <cmd> [args]...\n\n", argv0);
+	fprintf(stderr, "Execute a command with\n");
+	fprintf(stderr, "- SECBIT_EXEC_RESTRICT_FILE set: -f\n");
+	fprintf(stderr, "- SECBIT_EXEC_DENY_INTERACTIVE set: -i\n");
+}
+
+int main(const int argc, char *const argv[], char *const *const envp)
+{
+	const char *cmd_path;
+	char *const *cmd_argv;
+	int opt, secbits_cur, secbits_new;
+	bool has_policy = false;
+
+	secbits_cur = prctl(PR_GET_SECUREBITS);
+	if (secbits_cur == -1) {
+		/*
+		 * This should never happen, except with a buggy seccomp
+		 * filter.
+		 */
+		perror("ERROR: Failed to get securebits");
+		return 1;
+	}
+
+	secbits_new = secbits_cur;
+	while ((opt = getopt(argc, argv, "fi")) != -1) {
+		switch (opt) {
+		case 'f':
+			secbits_new |= SECBIT_EXEC_RESTRICT_FILE |
+				       SECBIT_EXEC_RESTRICT_FILE_LOCKED;
+			has_policy = true;
+			break;
+		case 'i':
+			secbits_new |= SECBIT_EXEC_DENY_INTERACTIVE |
+				       SECBIT_EXEC_DENY_INTERACTIVE_LOCKED;
+			has_policy = true;
+			break;
+		default:
+			print_usage(argv[0]);
+			return 1;
+		}
+	}
+
+	if (!argv[optind] || !has_policy) {
+		print_usage(argv[0]);
+		return 1;
+	}
+
+	if (secbits_cur != secbits_new &&
+	    prctl(PR_SET_SECUREBITS, secbits_new)) {
+		perror("Failed to set secure bit(s).");
+		fprintf(stderr,
+			"Hint: The running kernel may not support this feature.\n");
+		return 1;
+	}
+
+	cmd_path = argv[optind];
+	cmd_argv = argv + optind;
+	fprintf(stderr, "Executing command...\n");
+	execvpe(cmd_path, cmd_argv, envp);
+	fprintf(stderr, "Failed to execute \"%s\": %s\n", cmd_path,
+		strerror(errno));
+	return 1;
+}