Merge branch 'bpf-misc-selftest-improvements'

Joe Stringer says:

====================
This is series makes some minor changes primarily focused on making it easier
to understand why test_verifier is failing a test. This includes printing the
observed output when a test fails in a different way than expected, or when
unprivileged tests fail due to sysctl kernel.unprivileged_bpf_disabled=1. The
last patch removes some apparently dead code.
====================
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

kernel/bpf/verifier.c

@@ -508,10 +508,6 @@ static struct bpf_verifier_state *push_stack(struct bpf_verifier_env *env,
 static const int caller_saved[CALLER_SAVED_REGS] = {
 	BPF_REG_0, BPF_REG_1, BPF_REG_2, BPF_REG_3, BPF_REG_4, BPF_REG_5
 };
-#define CALLEE_SAVED_REGS 5
-static const int callee_saved[CALLEE_SAVED_REGS] = {
-	BPF_REG_6, BPF_REG_7, BPF_REG_8, BPF_REG_9
-};
 
 static void __mark_reg_not_init(struct bpf_reg_state *reg);
 

tools/testing/selftests/bpf/test_verifier.c

@@ -57,6 +57,9 @@
 #define F_NEEDS_EFFICIENT_UNALIGNED_ACCESS	(1 << 0)
 #define F_LOAD_WITH_STRICT_ALIGNMENT		(1 << 1)
 
+#define UNPRIV_SYSCTL "kernel/unprivileged_bpf_disabled"
+static bool unpriv_disabled = false;
+
 struct bpf_test {
 	const char *descr;
 	struct bpf_insn	insns[MAX_INSNS];
@@ -11291,7 +11294,8 @@ static void do_test_single(struct bpf_test *test, bool unpriv,
 			goto fail_log;
 		}
 		if (!strstr(bpf_vlog, expected_err) && !reject_from_alignment) {
-			printf("FAIL\nUnexpected error message!\n");
+			printf("FAIL\nUnexpected error message!\n\tEXP: %s\n\tRES: %s\n",
+			      expected_err, bpf_vlog);
 			goto fail_log;
 		}
 	}
@@ -11375,9 +11379,20 @@ static int set_admin(bool admin)
 	return ret;
 }
 
+static void get_unpriv_disabled()
+{
+	char buf[2];
+	FILE *fd;
+
+	fd = fopen("/proc/sys/"UNPRIV_SYSCTL, "r");
+	if (fgets(buf, 2, fd) == buf && atoi(buf))
+		unpriv_disabled = true;
+	fclose(fd);
+}
+
 static int do_test(bool unpriv, unsigned int from, unsigned int to)
 {
-	int i, passes = 0, errors = 0;
+	int i, passes = 0, errors = 0, skips = 0;
 
 	for (i = from; i < to; i++) {
 		struct bpf_test *test = &tests[i];
@@ -11385,7 +11400,10 @@ static int do_test(bool unpriv, unsigned int from, unsigned int to)
 		/* Program types that are not supported by non-root we
 		 * skip right away.
 		 */
-		if (!test->prog_type) {
+		if (!test->prog_type && unpriv_disabled) {
+			printf("#%d/u %s SKIP\n", i, test->descr);
+			skips++;
+		} else if (!test->prog_type) {
 			if (!unpriv)
 				set_admin(false);
 			printf("#%d/u %s ", i, test->descr);
@@ -11394,13 +11412,17 @@ static int do_test(bool unpriv, unsigned int from, unsigned int to)
 				set_admin(true);
 		}
 
-		if (!unpriv) {
+		if (unpriv) {
+			printf("#%d/p %s SKIP\n", i, test->descr);
+			skips++;
+		} else {
 			printf("#%d/p %s ", i, test->descr);
 			do_test_single(test, false, &passes, &errors);
 		}
 	}
 
-	printf("Summary: %d PASSED, %d FAILED\n", passes, errors);
+	printf("Summary: %d PASSED, %d SKIPPED, %d FAILED\n", passes,
+	       skips, errors);
 	return errors ? EXIT_FAILURE : EXIT_SUCCESS;
 }
 
@@ -11428,6 +11450,13 @@ int main(int argc, char **argv)
 		}
 	}
 
+	get_unpriv_disabled();
+	if (unpriv && unpriv_disabled) {
+		printf("Cannot run as unprivileged user with sysctl %s.\n",
+		       UNPRIV_SYSCTL);
+		return EXIT_FAILURE;
+	}
+
 	setrlimit(RLIMIT_MEMLOCK, unpriv ? &rlim : &rinf);
 	return do_test(unpriv, from, to);
 }