Merge branch 'bpf-kselftest-improvements'

Daniel Borkmann says:

====================
First one unifies the often repeated rlimit handling and the
second one enables and adds run-time tests for BPF tail calls
which provides useful coverage in particular for JITs.
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

tools/testing/selftests/bpf/bpf_rlimit.h

@@ -0,0 +1,28 @@
+#include <sys/resource.h>
+#include <stdio.h>
+
+static  __attribute__((constructor)) void bpf_rlimit_ctor(void)
+{
+	struct rlimit rlim_old, rlim_new = {
+		.rlim_cur	= RLIM_INFINITY,
+		.rlim_max	= RLIM_INFINITY,
+	};
+
+	getrlimit(RLIMIT_MEMLOCK, &rlim_old);
+	/* For the sake of running the test cases, we temporarily
+	 * set rlimit to infinity in order for kernel to focus on
+	 * errors from actual test cases and not getting noise
+	 * from hitting memlock limits. The limit is on per-process
+	 * basis and not a global one, hence destructor not really
+	 * needed here.
+	 */
+	if (setrlimit(RLIMIT_MEMLOCK, &rlim_new) < 0) {
+		perror("Unable to lift memlock rlimit");
+		/* Trying out lower limit, but expect potential test
+		 * case failures from this!
+		 */
+		rlim_new.rlim_cur = rlim_old.rlim_cur + (1UL << 20);
+		rlim_new.rlim_max = rlim_old.rlim_max + (1UL << 20);
+		setrlimit(RLIMIT_MEMLOCK, &rlim_new);
+	}
+}

tools/testing/selftests/bpf/test_align.c

@@ -9,8 +9,6 @@
 #include <stddef.h>
 #include <stdbool.h>
 
-#include <sys/resource.h>
-
 #include <linux/unistd.h>
 #include <linux/filter.h>
 #include <linux/bpf_perf_event.h>
@@ -19,6 +17,7 @@
 #include <bpf/bpf.h>
 
 #include "../../../include/linux/filter.h"
+#include "bpf_rlimit.h"
 
 #ifndef ARRAY_SIZE
 # define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
@@ -702,9 +701,6 @@ static int do_test(unsigned int from, unsigned int to)
 int main(int argc, char **argv)
 {
 	unsigned int from = 0, to = ARRAY_SIZE(tests);
-	struct rlimit rinf = { RLIM_INFINITY, RLIM_INFINITY };
-
-	setrlimit(RLIMIT_MEMLOCK, &rinf);
 
 	if (argc == 3) {
 		unsigned int l = atoi(argv[argc - 2]);

tools/testing/selftests/bpf/test_dev_cgroup.c

@@ -11,13 +11,13 @@
 #include <errno.h>
 #include <assert.h>
 #include <sys/time.h>
-#include <sys/resource.h>
 
 #include <linux/bpf.h>
 #include <bpf/bpf.h>
 #include <bpf/libbpf.h>
 
 #include "cgroup_helpers.h"
+#include "bpf_rlimit.h"
 
 #define DEV_CGROUP_PROG "./dev_cgroup.o"
 
@@ -25,15 +25,11 @@
 
 int main(int argc, char **argv)
 {
-	struct rlimit limit  = { RLIM_INFINITY, RLIM_INFINITY };
 	struct bpf_object *obj;
 	int error = EXIT_FAILURE;
 	int prog_fd, cgroup_fd;
 	__u32 prog_cnt;
 
-	if (setrlimit(RLIMIT_MEMLOCK, &limit) < 0)
-		perror("Unable to lift memlock rlimit");
-
 	if (bpf_prog_load(DEV_CGROUP_PROG, BPF_PROG_TYPE_CGROUP_DEVICE,
 			  &obj, &prog_fd)) {
 		printf("Failed to load DEV_CGROUP program\n");

tools/testing/selftests/bpf/test_lpm_map.c

@@ -22,10 +22,11 @@
 #include <unistd.h>
 #include <arpa/inet.h>
 #include <sys/time.h>
-#include <sys/resource.h>
 
 #include <bpf/bpf.h>
+
 #include "bpf_util.h"
+#include "bpf_rlimit.h"
 
 struct tlpm_node {
 	struct tlpm_node *next;
@@ -736,17 +737,11 @@ static void test_lpm_multi_thread(void)
 
 int main(void)
 {
-	struct rlimit limit  = { RLIM_INFINITY, RLIM_INFINITY };
-	int i, ret;
+	int i;
 
 	/* we want predictable, pseudo random tests */
 	srand(0xf00ba1);
 
-	/* allow unlimited locked memory */
-	ret = setrlimit(RLIMIT_MEMLOCK, &limit);
-	if (ret < 0)
-		perror("Unable to lift memlock rlimit");
-
 	test_lpm_basic();
 	test_lpm_order();
 
@@ -755,11 +750,8 @@ int main(void)
 		test_lpm_map(i);
 
 	test_lpm_ipaddr();
-
 	test_lpm_delete();
-
 	test_lpm_get_next_key();
-
 	test_lpm_multi_thread();
 
 	printf("test_lpm: OK\n");

tools/testing/selftests/bpf/test_lru_map.c

@@ -16,10 +16,11 @@
 #include <time.h>
 
 #include <sys/wait.h>
-#include <sys/resource.h>
 
 #include <bpf/bpf.h>
+
 #include "bpf_util.h"
+#include "bpf_rlimit.h"
 
 #define LOCAL_FREE_TARGET	(128)
 #define PERCPU_FREE_TARGET	(4)
@@ -613,7 +614,6 @@ static void test_lru_sanity6(int map_type, int map_flags, int tgt_free)
 
 int main(int argc, char **argv)
 {
-	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
 	int map_types[] = {BPF_MAP_TYPE_LRU_HASH,
 			     BPF_MAP_TYPE_LRU_PERCPU_HASH};
 	int map_flags[] = {0, BPF_F_NO_COMMON_LRU};
@@ -621,8 +621,6 @@ int main(int argc, char **argv)
 
 	setbuf(stdout, NULL);
 
-	assert(!setrlimit(RLIMIT_MEMLOCK, &r));
-
 	nr_cpus = bpf_num_possible_cpus();
 	assert(nr_cpus != -1);
 	printf("nr_cpus:%d\n\n", nr_cpus);

tools/testing/selftests/bpf/test_maps.c

@@ -17,13 +17,14 @@
 #include <stdlib.h>
 
 #include <sys/wait.h>
-#include <sys/resource.h>
 
 #include <linux/bpf.h>
 
 #include <bpf/bpf.h>
 #include <bpf/libbpf.h>
+
 #include "bpf_util.h"
+#include "bpf_rlimit.h"
 
 static int map_flags;
 
@@ -1126,10 +1127,6 @@ static void run_all_tests(void)
 
 int main(void)
 {
-	struct rlimit rinf = { RLIM_INFINITY, RLIM_INFINITY };
-
-	setrlimit(RLIMIT_MEMLOCK, &rinf);
-
 	map_flags = 0;
 	run_all_tests();
 

tools/testing/selftests/bpf/test_progs.c

@@ -26,7 +26,6 @@ typedef __u16 __sum16;
 
 #include <sys/ioctl.h>
 #include <sys/wait.h>
-#include <sys/resource.h>
 #include <sys/types.h>
 #include <fcntl.h>
 
@@ -34,9 +33,11 @@ typedef __u16 __sum16;
 #include <linux/err.h>
 #include <bpf/bpf.h>
 #include <bpf/libbpf.h>
+
 #include "test_iptunnel_common.h"
 #include "bpf_util.h"
 #include "bpf_endian.h"
+#include "bpf_rlimit.h"
 
 static int error_cnt, pass_cnt;
 
@@ -965,10 +966,6 @@ out:
 
 int main(void)
 {
-	struct rlimit rinf = { RLIM_INFINITY, RLIM_INFINITY };
-
-	setrlimit(RLIMIT_MEMLOCK, &rinf);
-
 	test_pkt_access();
 	test_xdp();
 	test_l4lb_all();

tools/testing/selftests/bpf/test_tag.c

@@ -12,7 +12,6 @@
 #include <assert.h>
 
 #include <sys/socket.h>
-#include <sys/resource.h>
 
 #include <linux/filter.h>
 #include <linux/bpf.h>
@@ -21,6 +20,7 @@
 #include <bpf/bpf.h>
 
 #include "../../../include/linux/filter.h"
+#include "bpf_rlimit.h"
 
 static struct bpf_insn prog[BPF_MAXINSNS];
 
@@ -184,11 +184,9 @@ static void do_test(uint32_t *tests, int start_insns, int fd_map,
 
 int main(void)
 {
-	struct rlimit rinf = { RLIM_INFINITY, RLIM_INFINITY };
 	uint32_t tests = 0;
 	int i, fd_map;
 
-	setrlimit(RLIMIT_MEMLOCK, &rinf);
 	fd_map = bpf_create_map(BPF_MAP_TYPE_HASH, sizeof(int),
 				sizeof(int), 1, BPF_F_NO_PREALLOC);
 	assert(fd_map > 0);

tools/testing/selftests/bpf/test_tcpbpf_user.c

@@ -12,13 +12,13 @@
 #include <linux/bpf.h>
 #include <sys/ioctl.h>
 #include <sys/time.h>
-#include <sys/resource.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <bpf/bpf.h>
 #include <bpf/libbpf.h>
 #include "bpf_util.h"
+#include "bpf_rlimit.h"
 #include <linux/perf_event.h>
 #include "test_tcpbpf.h"
 
@@ -44,7 +44,6 @@ static int bpf_find_map(const char *test, struct bpf_object *obj,
 
 int main(int argc, char **argv)
 {
-	struct rlimit limit  = { RLIM_INFINITY, RLIM_INFINITY };
 	const char *file = "test_tcpbpf_kern.o";
 	struct tcpbpf_globals g = {0};
 	int cg_fd, prog_fd, map_fd;
@@ -57,9 +56,6 @@ int main(int argc, char **argv)
 	int pid;
 	int rv;
 
-	if (setrlimit(RLIMIT_MEMLOCK, &limit) < 0)
-		perror("Unable to lift memlock rlimit");
-
 	if (argc > 1 && strcmp(argv[1], "-d") == 0)
 		debug_flag = true;
 

tools/testing/selftests/bpf/test_verifier.c

@@ -24,7 +24,6 @@
 #include <limits.h>
 
 #include <sys/capability.h>
-#include <sys/resource.h>
 
 #include <linux/unistd.h>
 #include <linux/filter.h>
@@ -41,7 +40,7 @@
 #  define CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS 1
 # endif
 #endif
-
+#include "bpf_rlimit.h"
 #include "../../../include/linux/filter.h"
 
 #ifndef ARRAY_SIZE
@@ -2589,6 +2588,62 @@ static struct bpf_test tests[] = {
 		.result_unpriv = REJECT,
 		.result = ACCEPT,
 	},
+	{
+		"runtime/jit: tail_call within bounds, prog once",
+		.insns = {
+			BPF_MOV64_IMM(BPF_REG_3, 0),
+			BPF_LD_MAP_FD(BPF_REG_2, 0),
+			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+				     BPF_FUNC_tail_call),
+			BPF_MOV64_IMM(BPF_REG_0, 1),
+			BPF_EXIT_INSN(),
+		},
+		.fixup_prog = { 1 },
+		.result = ACCEPT,
+		.retval = 42,
+	},
+	{
+		"runtime/jit: tail_call within bounds, prog loop",
+		.insns = {
+			BPF_MOV64_IMM(BPF_REG_3, 1),
+			BPF_LD_MAP_FD(BPF_REG_2, 0),
+			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+				     BPF_FUNC_tail_call),
+			BPF_MOV64_IMM(BPF_REG_0, 1),
+			BPF_EXIT_INSN(),
+		},
+		.fixup_prog = { 1 },
+		.result = ACCEPT,
+		.retval = 41,
+	},
+	{
+		"runtime/jit: tail_call within bounds, no prog",
+		.insns = {
+			BPF_MOV64_IMM(BPF_REG_3, 2),
+			BPF_LD_MAP_FD(BPF_REG_2, 0),
+			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+				     BPF_FUNC_tail_call),
+			BPF_MOV64_IMM(BPF_REG_0, 1),
+			BPF_EXIT_INSN(),
+		},
+		.fixup_prog = { 1 },
+		.result = ACCEPT,
+		.retval = 1,
+	},
+	{
+		"runtime/jit: tail_call out of bounds",
+		.insns = {
+			BPF_MOV64_IMM(BPF_REG_3, 256),
+			BPF_LD_MAP_FD(BPF_REG_2, 0),
+			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+				     BPF_FUNC_tail_call),
+			BPF_MOV64_IMM(BPF_REG_0, 2),
+			BPF_EXIT_INSN(),
+		},
+		.fixup_prog = { 1 },
+		.result = ACCEPT,
+		.retval = 2,
+	},
 	{
 		"runtime/jit: pass negative index to tail_call",
 		.insns = {
@@ -2596,11 +2651,12 @@ static struct bpf_test tests[] = {
 			BPF_LD_MAP_FD(BPF_REG_2, 0),
 			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
 				     BPF_FUNC_tail_call),
-			BPF_MOV64_IMM(BPF_REG_0, 0),
+			BPF_MOV64_IMM(BPF_REG_0, 2),
 			BPF_EXIT_INSN(),
 		},
 		.fixup_prog = { 1 },
 		.result = ACCEPT,
+		.retval = 2,
 	},
 	{
 		"runtime/jit: pass > 32bit index to tail_call",
@@ -2609,11 +2665,12 @@ static struct bpf_test tests[] = {
 			BPF_LD_MAP_FD(BPF_REG_2, 0),
 			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
 				     BPF_FUNC_tail_call),
-			BPF_MOV64_IMM(BPF_REG_0, 0),
+			BPF_MOV64_IMM(BPF_REG_0, 2),
 			BPF_EXIT_INSN(),
 		},
 		.fixup_prog = { 2 },
 		.result = ACCEPT,
+		.retval = 42,
 	},
 	{
 		"stack pointer arithmetic",
@@ -11279,16 +11336,61 @@ static int create_map(uint32_t size_value, uint32_t max_elem)
 	return fd;
 }
 
+static int create_prog_dummy1(void)
+{
+	struct bpf_insn prog[] = {
+		BPF_MOV64_IMM(BPF_REG_0, 42),
+		BPF_EXIT_INSN(),
+	};
+
+	return bpf_load_program(BPF_PROG_TYPE_SOCKET_FILTER, prog,
+				ARRAY_SIZE(prog), "GPL", 0, NULL, 0);
+}
+
+static int create_prog_dummy2(int mfd, int idx)
+{
+	struct bpf_insn prog[] = {
+		BPF_MOV64_IMM(BPF_REG_3, idx),
+		BPF_LD_MAP_FD(BPF_REG_2, mfd),
+		BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+			     BPF_FUNC_tail_call),
+		BPF_MOV64_IMM(BPF_REG_0, 41),
+		BPF_EXIT_INSN(),
+	};
+
+	return bpf_load_program(BPF_PROG_TYPE_SOCKET_FILTER, prog,
+				ARRAY_SIZE(prog), "GPL", 0, NULL, 0);
+}
+
 static int create_prog_array(void)
 {
-	int fd;
+	int p1key = 0, p2key = 1;
+	int mfd, p1fd, p2fd;
 
-	fd = bpf_create_map(BPF_MAP_TYPE_PROG_ARRAY, sizeof(int),
-			    sizeof(int), 4, 0);
-	if (fd < 0)
+	mfd = bpf_create_map(BPF_MAP_TYPE_PROG_ARRAY, sizeof(int),
+			     sizeof(int), 4, 0);
+	if (mfd < 0) {
 		printf("Failed to create prog array '%s'!\n", strerror(errno));
+		return -1;
+	}
 
-	return fd;
+	p1fd = create_prog_dummy1();
+	p2fd = create_prog_dummy2(mfd, p2key);
+	if (p1fd < 0 || p2fd < 0)
+		goto out;
+	if (bpf_map_update_elem(mfd, &p1key, &p1fd, BPF_ANY) < 0)
+		goto out;
+	if (bpf_map_update_elem(mfd, &p2key, &p2fd, BPF_ANY) < 0)
+		goto out;
+	close(p2fd);
+	close(p1fd);
+
+	return mfd;
+out:
+	close(p2fd);
+	close(p1fd);
+	close(mfd);
+	return -1;
 }
 
 static int create_map_in_map(void)
@@ -11543,8 +11645,6 @@ static int do_test(bool unpriv, unsigned int from, unsigned int to)
 
 int main(int argc, char **argv)
 {
-	struct rlimit rinf = { RLIM_INFINITY, RLIM_INFINITY };
-	struct rlimit rlim = { 1 << 20, 1 << 20 };
 	unsigned int from = 0, to = ARRAY_SIZE(tests);
 	bool unpriv = !is_admin();
 
@@ -11572,6 +11672,5 @@ int main(int argc, char **argv)
 		return EXIT_FAILURE;
 	}
 
-	setrlimit(RLIMIT_MEMLOCK, unpriv ? &rlim : &rinf);
 	return do_test(unpriv, from, to);
 }

tools/testing/selftests/bpf/test_verifier_log.c

@@ -4,7 +4,6 @@
 #include <string.h>
 #include <unistd.h>
 #include <sys/time.h>
-#include <sys/resource.h>
 
 #include <linux/bpf.h>
 #include <linux/filter.h>
@@ -12,6 +11,8 @@
 
 #include <bpf/bpf.h>
 
+#include "bpf_rlimit.h"
+
 #define LOG_SIZE (1 << 20)
 
 #define err(str...)	printf("ERROR: " str)
@@ -133,16 +134,11 @@ static void test_log_bad(char *log, size_t log_len, int log_level)
 
 int main(int argc, char **argv)
 {
-	struct rlimit limit  = { RLIM_INFINITY, RLIM_INFINITY };
 	char full_log[LOG_SIZE];
 	char log[LOG_SIZE];
 	size_t want_len;
 	int i;
 
-	/* allow unlimited locked memory to have more consistent error code */
-	if (setrlimit(RLIMIT_MEMLOCK, &limit) < 0)
-		perror("Unable to lift memlock rlimit");
-
 	memset(log, 1, LOG_SIZE);
 
 	/* Test incorrect attr */