Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Alexei Starovoitov says:

====================
pull-request: bpf-next 2020-07-13

The following pull-request contains BPF updates for your *net-next* tree.

We've added 36 non-merge commits during the last 7 day(s) which contain
a total of 62 files changed, 2242 insertions(+), 468 deletions(-).

The main changes are:

1) Avoid trace_printk warning banner by switching bpf_trace_printk to use
   its own tracing event, from Alan.

2) Better libbpf support on older kernels, from Andrii.

3) Additional AF_XDP stats, from Ciara.

4) build time resolution of BTF IDs, from Jiri.

5) BPF_CGROUP_INET_SOCK_RELEASE hook, from Stanislav.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/selftests/bpf/Makefile

@@ -111,6 +111,7 @@ SCRATCH_DIR := $(OUTPUT)/tools
 BUILD_DIR := $(SCRATCH_DIR)/build
 INCLUDE_DIR := $(SCRATCH_DIR)/include
 BPFOBJ := $(BUILD_DIR)/libbpf/libbpf.a
+RESOLVE_BTFIDS := $(BUILD_DIR)/resolve_btfids/resolve_btfids
 
 # Define simple and short `make test_progs`, `make test_sysctl`, etc targets
 # to build individual tests.
@@ -177,7 +178,7 @@ $(BPFOBJ): $(wildcard $(BPFDIR)/*.[ch] $(BPFDIR)/Makefile)		       \
 	$(Q)$(MAKE) $(submake_extras) -C $(BPFDIR) OUTPUT=$(BUILD_DIR)/libbpf/ \
 		    DESTDIR=$(SCRATCH_DIR) prefix= all install_headers
 
-$(BUILD_DIR)/libbpf $(BUILD_DIR)/bpftool $(INCLUDE_DIR):
+$(BUILD_DIR)/libbpf $(BUILD_DIR)/bpftool $(BUILD_DIR)/resolve_btfids $(INCLUDE_DIR):
 	$(call msg,MKDIR,,$@)
 	mkdir -p $@
 
@@ -190,6 +191,16 @@ else
 	cp "$(VMLINUX_H)" $@
 endif
 
+$(RESOLVE_BTFIDS): $(BPFOBJ) | $(BUILD_DIR)/resolve_btfids	\
+		       $(TOOLSDIR)/bpf/resolve_btfids/main.c	\
+		       $(TOOLSDIR)/lib/rbtree.c			\
+		       $(TOOLSDIR)/lib/zalloc.c			\
+		       $(TOOLSDIR)/lib/string.c			\
+		       $(TOOLSDIR)/lib/ctype.c			\
+		       $(TOOLSDIR)/lib/str_error_r.c
+	$(Q)$(MAKE) $(submake_extras) -C $(TOOLSDIR)/bpf/resolve_btfids	\
+		OUTPUT=$(BUILD_DIR)/resolve_btfids/ BPFOBJ=$(BPFOBJ)
+
 # Get Clang's default includes on this system, as opposed to those seen by
 # '-target bpf'. This fixes "missing" files on some architectures/distros,
 # such as asm/byteorder.h, asm/socket.h, asm/sockios.h, sys/cdefs.h etc.
@@ -352,9 +363,11 @@ endif
 
 $(OUTPUT)/$(TRUNNER_BINARY): $(TRUNNER_TEST_OBJS)			\
 			     $(TRUNNER_EXTRA_OBJS) $$(BPFOBJ)		\
+			     $(RESOLVE_BTFIDS)				\
 			     | $(TRUNNER_BINARY)-extras
 	$$(call msg,BINARY,,$$@)
 	$$(CC) $$(CFLAGS) $$(filter %.a %.o,$$^) $$(LDLIBS) -o $$@
+	$(RESOLVE_BTFIDS) --no-fail --btf btf_data.o $$@
 
 endef
 

tools/testing/selftests/bpf/bpf_legacy.h

@@ -2,20 +2,6 @@
 #ifndef __BPF_LEGACY__
 #define __BPF_LEGACY__
 
-/*
- * legacy bpf_map_def with extra fields supported only by bpf_load(), do not
- * use outside of samples/bpf
- */
-struct bpf_map_def_legacy {
-	unsigned int type;
-	unsigned int key_size;
-	unsigned int value_size;
-	unsigned int max_entries;
-	unsigned int map_flags;
-	unsigned int inner_map_idx;
-	unsigned int numa_node;
-};
-
 #define BPF_ANNOTATE_KV_PAIR(name, type_key, type_val)		\
 	struct ____btf_map_##name {				\
 		type_key key;					\

tools/testing/selftests/bpf/prog_tests/core_retro.c

@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2020 Facebook
+#define _GNU_SOURCE
+#include <test_progs.h>
+#include "test_core_retro.skel.h"
+
+void test_core_retro(void)
+{
+	int err, zero = 0, res, duration = 0;
+	struct test_core_retro *skel;
+
+	/* load program */
+	skel = test_core_retro__open_and_load();
+	if (CHECK(!skel, "skel_load", "skeleton open/load failed\n"))
+		goto out_close;
+
+	/* attach probe */
+	err = test_core_retro__attach(skel);
+	if (CHECK(err, "attach_kprobe", "err %d\n", err))
+		goto out_close;
+
+	/* trigger */
+	usleep(1);
+
+	err = bpf_map_lookup_elem(bpf_map__fd(skel->maps.results), &zero, &res);
+	if (CHECK(err, "map_lookup", "failed to lookup result: %d\n", errno))
+		goto out_close;
+
+	CHECK(res != getpid(), "pid_check", "got %d != exp %d\n", res, getpid());
+
+out_close:
+	test_core_retro__destroy(skel);
+}

tools/testing/selftests/bpf/prog_tests/perf_buffer.c

@@ -4,6 +4,7 @@
 #include <sched.h>
 #include <sys/socket.h>
 #include <test_progs.h>
+#include "test_perf_buffer.skel.h"
 #include "bpf/libbpf_internal.h"
 
 /* AddressSanitizer sometimes crashes due to data dereference below, due to
@@ -25,16 +26,11 @@ static void on_sample(void *ctx, int cpu, void *data, __u32 size)
 
 void test_perf_buffer(void)
 {
-	int err, prog_fd, on_len, nr_on_cpus = 0,  nr_cpus, i, duration = 0;
-	const char *prog_name = "kprobe/sys_nanosleep";
-	const char *file = "./test_perf_buffer.o";
+	int err, on_len, nr_on_cpus = 0,  nr_cpus, i, duration = 0;
 	struct perf_buffer_opts pb_opts = {};
-	struct bpf_map *perf_buf_map;
+	struct test_perf_buffer *skel;
 	cpu_set_t cpu_set, cpu_seen;
-	struct bpf_program *prog;
-	struct bpf_object *obj;
 	struct perf_buffer *pb;
-	struct bpf_link *link;
 	bool *online;
 
 	nr_cpus = libbpf_num_possible_cpus();
@@ -51,33 +47,21 @@ void test_perf_buffer(void)
 			nr_on_cpus++;
 
 	/* load program */
-	err = bpf_prog_load(file, BPF_PROG_TYPE_KPROBE, &obj, &prog_fd);
-	if (CHECK(err, "obj_load", "err %d errno %d\n", err, errno)) {
-		obj = NULL;
-		goto out_close;
-	}
-
-	prog = bpf_object__find_program_by_title(obj, prog_name);
-	if (CHECK(!prog, "find_probe", "prog '%s' not found\n", prog_name))
+	skel = test_perf_buffer__open_and_load();
+	if (CHECK(!skel, "skel_load", "skeleton open/load failed\n"))
 		goto out_close;
 
-	/* load map */
-	perf_buf_map = bpf_object__find_map_by_name(obj, "perf_buf_map");
-	if (CHECK(!perf_buf_map, "find_perf_buf_map", "not found\n"))
-		goto out_close;
-
-	/* attach kprobe */
-	link = bpf_program__attach_kprobe(prog, false /* retprobe */,
-					  SYS_NANOSLEEP_KPROBE_NAME);
-	if (CHECK(IS_ERR(link), "attach_kprobe", "err %ld\n", PTR_ERR(link)))
+	/* attach probe */
+	err = test_perf_buffer__attach(skel);
+	if (CHECK(err, "attach_kprobe", "err %d\n", err))
 		goto out_close;
 
 	/* set up perf buffer */
 	pb_opts.sample_cb = on_sample;
 	pb_opts.ctx = &cpu_seen;
-	pb = perf_buffer__new(bpf_map__fd(perf_buf_map), 1, &pb_opts);
+	pb = perf_buffer__new(bpf_map__fd(skel->maps.perf_buf_map), 1, &pb_opts);
 	if (CHECK(IS_ERR(pb), "perf_buf__new", "err %ld\n", PTR_ERR(pb)))
-		goto out_detach;
+		goto out_close;
 
 	/* trigger kprobe on every CPU */
 	CPU_ZERO(&cpu_seen);
@@ -94,7 +78,7 @@ void test_perf_buffer(void)
 					     &cpu_set);
 		if (err && CHECK(err, "set_affinity", "cpu #%d, err %d\n",
 				 i, err))
-			goto out_detach;
+			goto out_close;
 
 		usleep(1);
 	}
@@ -110,9 +94,7 @@ void test_perf_buffer(void)
 
 out_free_pb:
 	perf_buffer__free(pb);
-out_detach:
-	bpf_link__destroy(link);
 out_close:
-	bpf_object__close(obj);
+	test_perf_buffer__destroy(skel);
 	free(online);
 }

tools/testing/selftests/bpf/prog_tests/resolve_btfids.c

@@ -0,0 +1,111 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/err.h>
+#include <string.h>
+#include <bpf/btf.h>
+#include <bpf/libbpf.h>
+#include <linux/btf.h>
+#include <linux/kernel.h>
+#include <linux/btf_ids.h>
+#include "test_progs.h"
+
+static int duration;
+
+struct symbol {
+	const char	*name;
+	int		 type;
+	int		 id;
+};
+
+struct symbol test_symbols[] = {
+	{ "unused",  BTF_KIND_UNKN,     0 },
+	{ "S",       BTF_KIND_TYPEDEF, -1 },
+	{ "T",       BTF_KIND_TYPEDEF, -1 },
+	{ "U",       BTF_KIND_TYPEDEF, -1 },
+	{ "S",       BTF_KIND_STRUCT,  -1 },
+	{ "U",       BTF_KIND_UNION,   -1 },
+	{ "func",    BTF_KIND_FUNC,    -1 },
+};
+
+BTF_ID_LIST(test_list)
+BTF_ID_UNUSED
+BTF_ID(typedef, S)
+BTF_ID(typedef, T)
+BTF_ID(typedef, U)
+BTF_ID(struct,  S)
+BTF_ID(union,   U)
+BTF_ID(func,    func)
+
+static int
+__resolve_symbol(struct btf *btf, int type_id)
+{
+	const struct btf_type *type;
+	const char *str;
+	unsigned int i;
+
+	type = btf__type_by_id(btf, type_id);
+	if (!type) {
+		PRINT_FAIL("Failed to get type for ID %d\n", type_id);
+		return -1;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(test_symbols); i++) {
+		if (test_symbols[i].id != -1)
+			continue;
+
+		if (BTF_INFO_KIND(type->info) != test_symbols[i].type)
+			continue;
+
+		str = btf__name_by_offset(btf, type->name_off);
+		if (!str) {
+			PRINT_FAIL("Failed to get name for BTF ID %d\n", type_id);
+			return -1;
+		}
+
+		if (!strcmp(str, test_symbols[i].name))
+			test_symbols[i].id = type_id;
+	}
+
+	return 0;
+}
+
+static int resolve_symbols(void)
+{
+	struct btf *btf;
+	int type_id;
+	__u32 nr;
+
+	btf = btf__parse_elf("btf_data.o", NULL);
+	if (CHECK(libbpf_get_error(btf), "resolve",
+		  "Failed to load BTF from btf_data.o\n"))
+		return -1;
+
+	nr = btf__get_nr_types(btf);
+
+	for (type_id = 1; type_id <= nr; type_id++) {
+		if (__resolve_symbol(btf, type_id))
+			break;
+	}
+
+	btf__free(btf);
+	return 0;
+}
+
+int test_resolve_btfids(void)
+{
+	unsigned int i;
+	int ret = 0;
+
+	if (resolve_symbols())
+		return -1;
+
+	/* Check BTF_ID_LIST(test_list) IDs */
+	for (i = 0; i < ARRAY_SIZE(test_symbols) && !ret; i++) {
+		ret = CHECK(test_list[i] != test_symbols[i].id,
+			    "id_check",
+			    "wrong ID for %s (%d != %d)\n", test_symbols[i].name,
+			    test_list[i], test_symbols[i].id);
+	}
+
+	return ret;
+}

tools/testing/selftests/bpf/prog_tests/skeleton.c

@@ -41,7 +41,7 @@ void test_skeleton(void)
 	CHECK(bss->in4 != 0, "in4", "got %lld != exp %lld\n", bss->in4, 0LL);
 	CHECK(bss->out4 != 0, "out4", "got %lld != exp %lld\n", bss->out4, 0LL);
 
-	CHECK(rodata->in6 != 0, "in6", "got %d != exp %d\n", rodata->in6, 0);
+	CHECK(rodata->in.in6 != 0, "in6", "got %d != exp %d\n", rodata->in.in6, 0);
 	CHECK(bss->out6 != 0, "out6", "got %d != exp %d\n", bss->out6, 0);
 
 	/* validate we can pre-setup global variables, even in .bss */
@@ -49,7 +49,7 @@ void test_skeleton(void)
 	data->in2 = 11;
 	bss->in3 = 12;
 	bss->in4 = 13;
-	rodata->in6 = 14;
+	rodata->in.in6 = 14;
 
 	err = test_skeleton__load(skel);
 	if (CHECK(err, "skel_load", "failed to load skeleton: %d\n", err))
@@ -60,7 +60,7 @@ void test_skeleton(void)
 	CHECK(data->in2 != 11, "in2", "got %lld != exp %lld\n", data->in2, 11LL);
 	CHECK(bss->in3 != 12, "in3", "got %d != exp %d\n", bss->in3, 12);
 	CHECK(bss->in4 != 13, "in4", "got %lld != exp %lld\n", bss->in4, 13LL);
-	CHECK(rodata->in6 != 14, "in6", "got %d != exp %d\n", rodata->in6, 14);
+	CHECK(rodata->in.in6 != 14, "in6", "got %d != exp %d\n", rodata->in.in6, 14);
 
 	/* now set new values and attach to get them into outX variables */
 	data->in1 = 1;

tools/testing/selftests/bpf/prog_tests/trace_printk.c

@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2020, Oracle and/or its affiliates. */
+
+#include <test_progs.h>
+
+#include "trace_printk.skel.h"
+
+#define TRACEBUF	"/sys/kernel/debug/tracing/trace_pipe"
+#define SEARCHMSG	"testing,testing"
+
+void test_trace_printk(void)
+{
+	int err, iter = 0, duration = 0, found = 0;
+	struct trace_printk__bss *bss;
+	struct trace_printk *skel;
+	char *buf = NULL;
+	FILE *fp = NULL;
+	size_t buflen;
+
+	skel = trace_printk__open();
+	if (CHECK(!skel, "skel_open", "failed to open skeleton\n"))
+		return;
+
+	err = trace_printk__load(skel);
+	if (CHECK(err, "skel_load", "failed to load skeleton: %d\n", err))
+		goto cleanup;
+
+	bss = skel->bss;
+
+	err = trace_printk__attach(skel);
+	if (CHECK(err, "skel_attach", "skeleton attach failed: %d\n", err))
+		goto cleanup;
+
+	fp = fopen(TRACEBUF, "r");
+	if (CHECK(fp == NULL, "could not open trace buffer",
+		  "error %d opening %s", errno, TRACEBUF))
+		goto cleanup;
+
+	/* We do not want to wait forever if this test fails... */
+	fcntl(fileno(fp), F_SETFL, O_NONBLOCK);
+
+	/* wait for tracepoint to trigger */
+	usleep(1);
+	trace_printk__detach(skel);
+
+	if (CHECK(bss->trace_printk_ran == 0,
+		  "bpf_trace_printk never ran",
+		  "ran == %d", bss->trace_printk_ran))
+		goto cleanup;
+
+	if (CHECK(bss->trace_printk_ret <= 0,
+		  "bpf_trace_printk returned <= 0 value",
+		  "got %d", bss->trace_printk_ret))
+		goto cleanup;
+
+	/* verify our search string is in the trace buffer */
+	while (getline(&buf, &buflen, fp) >= 0 || errno == EAGAIN) {
+		if (strstr(buf, SEARCHMSG) != NULL)
+			found++;
+		if (found == bss->trace_printk_ran)
+			break;
+		if (++iter > 1000)
+			break;
+	}
+
+	if (CHECK(!found, "message from bpf_trace_printk not found",
+		  "no instance of %s in %s", SEARCHMSG, TRACEBUF))
+		goto cleanup;
+
+cleanup:
+	trace_printk__destroy(skel);
+	free(buf);
+	if (fp)
+		fclose(fp);
+}

tools/testing/selftests/bpf/prog_tests/udp_limit.c

@@ -0,0 +1,75 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <test_progs.h>
+#include "udp_limit.skel.h"
+
+#include <sys/types.h>
+#include <sys/socket.h>
+
+static int duration;
+
+void test_udp_limit(void)
+{
+	struct udp_limit *skel;
+	int fd1 = -1, fd2 = -1;
+	int cgroup_fd;
+
+	cgroup_fd = test__join_cgroup("/udp_limit");
+	if (CHECK(cgroup_fd < 0, "cg-join", "errno %d", errno))
+		return;
+
+	skel = udp_limit__open_and_load();
+	if (CHECK(!skel, "skel-load", "errno %d", errno))
+		goto close_cgroup_fd;
+
+	skel->links.sock = bpf_program__attach_cgroup(skel->progs.sock, cgroup_fd);
+	skel->links.sock_release = bpf_program__attach_cgroup(skel->progs.sock_release, cgroup_fd);
+	if (CHECK(IS_ERR(skel->links.sock) || IS_ERR(skel->links.sock_release),
+		  "cg-attach", "sock %ld sock_release %ld",
+		  PTR_ERR(skel->links.sock),
+		  PTR_ERR(skel->links.sock_release)))
+		goto close_skeleton;
+
+	/* BPF program enforces a single UDP socket per cgroup,
+	 * verify that.
+	 */
+	fd1 = socket(AF_INET, SOCK_DGRAM, 0);
+	if (CHECK(fd1 < 0, "fd1", "errno %d", errno))
+		goto close_skeleton;
+
+	fd2 = socket(AF_INET, SOCK_DGRAM, 0);
+	if (CHECK(fd2 >= 0, "fd2", "errno %d", errno))
+		goto close_skeleton;
+
+	/* We can reopen again after close. */
+	close(fd1);
+	fd1 = -1;
+
+	fd1 = socket(AF_INET, SOCK_DGRAM, 0);
+	if (CHECK(fd1 < 0, "fd1-again", "errno %d", errno))
+		goto close_skeleton;
+
+	/* Make sure the program was invoked the expected
+	 * number of times:
+	 * - open fd1           - BPF_CGROUP_INET_SOCK_CREATE
+	 * - attempt to openfd2 - BPF_CGROUP_INET_SOCK_CREATE
+	 * - close fd1          - BPF_CGROUP_INET_SOCK_RELEASE
+	 * - open fd1 again     - BPF_CGROUP_INET_SOCK_CREATE
+	 */
+	if (CHECK(skel->bss->invocations != 4, "bss-invocations",
+		  "invocations=%d", skel->bss->invocations))
+		goto close_skeleton;
+
+	/* We should still have a single socket in use */
+	if (CHECK(skel->bss->in_use != 1, "bss-in_use",
+		  "in_use=%d", skel->bss->in_use))
+		goto close_skeleton;
+
+close_skeleton:
+	if (fd1 >= 0)
+		close(fd1);
+	if (fd2 >= 0)
+		close(fd2);
+	udp_limit__destroy(skel);
+close_cgroup_fd:
+	close(cgroup_fd);
+}

tools/testing/selftests/bpf/progs/btf_data.c

@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+
+struct S {
+	int	a;
+	int	b;
+	int	c;
+};
+
+union U {
+	int	a;
+	int	b;
+	int	c;
+};
+
+struct S1 {
+	int	a;
+	int	b;
+	int	c;
+};
+
+union U1 {
+	int	a;
+	int	b;
+	int	c;
+};
+
+typedef int T;
+typedef int S;
+typedef int U;
+typedef int T1;
+typedef int S1;
+typedef int U1;
+
+struct root_struct {
+	S		m_1;
+	T		m_2;
+	U		m_3;
+	S1		m_4;
+	T1		m_5;
+	U1		m_6;
+	struct S	m_7;
+	struct S1	m_8;
+	union  U	m_9;
+	union  U1	m_10;
+};
+
+int func(struct root_struct *root)
+{
+	return 0;
+}

tools/testing/selftests/bpf/progs/test_core_retro.c

@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2020 Facebook
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_core_read.h>
+
+struct task_struct {
+	int tgid;
+} __attribute__((preserve_access_index));
+
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__uint(max_entries, 1);
+	__type(key, int);
+	__type(value, int);
+} results SEC(".maps");
+
+SEC("tp/raw_syscalls/sys_enter")
+int handle_sys_enter(void *ctx)
+{
+	struct task_struct *task = (void *)bpf_get_current_task();
+	int tgid = BPF_CORE_READ(task, tgid);
+	int zero = 0;
+
+	bpf_map_update_elem(&results, &zero, &tgid, 0);
+
+	return 0;
+}
+
+char _license[] SEC("license") = "GPL";

tools/testing/selftests/bpf/progs/test_perf_buffer.c

@@ -12,8 +12,8 @@ struct {
 	__uint(value_size, sizeof(int));
 } perf_buf_map SEC(".maps");
 
-SEC("kprobe/sys_nanosleep")
-int BPF_KPROBE(handle_sys_nanosleep_entry)
+SEC("tp/raw_syscalls/sys_enter")
+int handle_sys_enter(void *ctx)
 {
 	int cpu = bpf_get_smp_processor_id();
 

tools/testing/selftests/bpf/progs/test_skeleton.c

@@ -20,7 +20,9 @@ long long in4 __attribute__((aligned(64))) = 0;
 struct s in5 = {};
 
 /* .rodata section */
-const volatile int in6 = 0;
+const volatile struct {
+	const int in6;
+} in = {};
 
 /* .data section */
 int out1 = -1;
@@ -46,7 +48,7 @@ int handler(const void *ctx)
 	out3 = in3;
 	out4 = in4;
 	out5 = in5;
-	out6 = in6;
+	out6 = in.in6;
 
 	bpf_syscall = CONFIG_BPF_SYSCALL;
 	kern_ver = LINUX_KERNEL_VERSION;

tools/testing/selftests/bpf/progs/trace_printk.c

@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2020, Oracle and/or its affiliates.
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+char _license[] SEC("license") = "GPL";
+
+int trace_printk_ret = 0;
+int trace_printk_ran = 0;
+
+SEC("tp/raw_syscalls/sys_enter")
+int sys_enter(void *ctx)
+{
+	static const char fmt[] = "testing,testing %d\n";
+
+	trace_printk_ret = bpf_trace_printk(fmt, sizeof(fmt),
+					    ++trace_printk_ran);
+	return 0;
+}

tools/testing/selftests/bpf/progs/udp_limit.c

@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <sys/socket.h>
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+int invocations = 0, in_use = 0;
+
+SEC("cgroup/sock_create")
+int sock(struct bpf_sock *ctx)
+{
+	__u32 key;
+
+	if (ctx->type != SOCK_DGRAM)
+		return 1;
+
+	__sync_fetch_and_add(&invocations, 1);
+
+	if (in_use > 0) {
+		/* BPF_CGROUP_INET_SOCK_RELEASE is _not_ called
+		 * when we return an error from the BPF
+		 * program!
+		 */
+		return 0;
+	}
+
+	__sync_fetch_and_add(&in_use, 1);
+	return 1;
+}
+
+SEC("cgroup/sock_release")
+int sock_release(struct bpf_sock *ctx)
+{
+	__u32 key;
+
+	if (ctx->type != SOCK_DGRAM)
+		return 1;
+
+	__sync_fetch_and_add(&invocations, 1);
+	__sync_fetch_and_add(&in_use, -1);
+	return 1;
+}

tools/testing/selftests/bpf/test_progs.c

@@ -12,6 +12,9 @@
 #include <string.h>
 #include <execinfo.h> /* backtrace */
 
+#define EXIT_NO_TEST		2
+#define EXIT_ERR_SETUP_INFRA	3
+
 /* defined in test_progs.h */
 struct test_env env = {};
 
@@ -111,13 +114,13 @@ static void reset_affinity() {
 	if (err < 0) {
 		stdio_restore();
 		fprintf(stderr, "Failed to reset process affinity: %d!\n", err);
-		exit(-1);
+		exit(EXIT_ERR_SETUP_INFRA);
 	}
 	err = pthread_setaffinity_np(pthread_self(), sizeof(cpuset), &cpuset);
 	if (err < 0) {
 		stdio_restore();
 		fprintf(stderr, "Failed to reset thread affinity: %d!\n", err);
-		exit(-1);
+		exit(EXIT_ERR_SETUP_INFRA);
 	}
 }
 
@@ -126,7 +129,7 @@ static void save_netns(void)
 	env.saved_netns_fd = open("/proc/self/ns/net", O_RDONLY);
 	if (env.saved_netns_fd == -1) {
 		perror("open(/proc/self/ns/net)");
-		exit(-1);
+		exit(EXIT_ERR_SETUP_INFRA);
 	}
 }
 
@@ -135,7 +138,7 @@ static void restore_netns(void)
 	if (setns(env.saved_netns_fd, CLONE_NEWNET) == -1) {
 		stdio_restore();
 		perror("setns(CLONE_NEWNS)");
-		exit(-1);
+		exit(EXIT_ERR_SETUP_INFRA);
 	}
 }
 
@@ -740,7 +743,7 @@ out:
 	close(env.saved_netns_fd);
 
 	if (env.succ_cnt + env.fail_cnt + env.skip_cnt == 0)
-		return EXIT_FAILURE;
+		return EXIT_NO_TEST;
 
 	return env.fail_cnt ? EXIT_FAILURE : EXIT_SUCCESS;
 }