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

Alexei Starovoitov says:

====================
pull-request: bpf 2020-11-06

1) Pre-allocated per-cpu hashmap needs to zero-fill reused element, from David.

2) Tighten bpf_lsm function check, from KP.

3) Fix bpftool attaching to flow dissector, from Lorenz.

4) Use -fno-gcse for the whole kernel/bpf/core.c instead of function attribute, from Ard.

* git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  bpf: Update verification logic for LSM programs
  bpf: Zero-fill re-used per-cpu map element
  bpf: BPF_PRELOAD depends on BPF_SYSCALL
  tools/bpftool: Fix attaching flow dissector
  libbpf: Fix possible use after free in xsk_socket__delete
  libbpf: Fix null dereference in xsk_socket__delete
  libbpf, hashmap: Fix undefined behavior in hash_bits
  bpf: Don't rely on GCC __attribute__((optimize)) to disable GCSE
  tools, bpftool: Remove two unused variables.
  tools, bpftool: Avoid array index warnings.
  xsk: Fix possible memory leak at socket close
  bpf: Add struct bpf_redir_neigh forward declaration to BPF helper defs
  samples/bpf: Set rlimit for memlock to infinity in all samples
  bpf: Fix -Wshadow warnings
  selftest/bpf: Fix profiler test using CO-RE relocation for enums
====================

Link: https://lore.kernel.org/r/20201106221759.24143-1-alexei.starovoitov@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

8 files changed, 279 insertions, 16 deletions

diff --git a/tools/bpf/bpftool/feature.c b/tools/bpf/bpftool/feature.c
index a43a6f10b564..359960a8f1de 100644
--- a/tools/bpf/bpftool/feature.c
+++ b/tools/bpf/bpftool/feature.c
@@ -843,9 +843,14 @@ static int handle_perms(void)
 		else
 			p_err("missing %s%s%s%s%s%s%s%srequired for full feature probing; run as root or use 'unprivileged'",
 			      capability_msg(bpf_caps, 0),
+#ifdef CAP_BPF
 			      capability_msg(bpf_caps, 1),
 			      capability_msg(bpf_caps, 2),
-			      capability_msg(bpf_caps, 3));
+			      capability_msg(bpf_caps, 3)
+#else
+				"", "", "", "", "", ""
+#endif /* CAP_BPF */
+				);
 		goto exit_free;
 	}
 
diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index d942c1e3372c..acdb2c245f0a 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -940,7 +940,7 @@ static int parse_attach_detach_args(int argc, char **argv, int *progfd,
 	}
 
 	if (*attach_type == BPF_FLOW_DISSECTOR) {
-		*mapfd = -1;
+		*mapfd = 0;
 		return 0;
 	}
 
diff --git a/tools/bpf/bpftool/skeleton/profiler.bpf.c b/tools/bpf/bpftool/skeleton/profiler.bpf.c
index 4e3512f700c0..ce5b65e07ab1 100644
--- a/tools/bpf/bpftool/skeleton/profiler.bpf.c
+++ b/tools/bpf/bpftool/skeleton/profiler.bpf.c
@@ -70,7 +70,7 @@ int BPF_PROG(fentry_XXX)
 static inline void
 fexit_update_maps(u32 id, struct bpf_perf_event_value *after)
 {
-	struct bpf_perf_event_value *before, diff, *accum;
+	struct bpf_perf_event_value *before, diff;
 
 	before = bpf_map_lookup_elem(&fentry_readings, &id);
 	/* only account samples with a valid fentry_reading */
@@ -95,7 +95,7 @@ int BPF_PROG(fexit_XXX)
 {
 	struct bpf_perf_event_value readings[MAX_NUM_MATRICS];
 	u32 cpu = bpf_get_smp_processor_id();
-	u32 i, one = 1, zero = 0;
+	u32 i, zero = 0;
 	int err;
 	u64 *count;
 
diff --git a/tools/lib/bpf/hashmap.h b/tools/lib/bpf/hashmap.h
index d9b385fe808c..10a4c4cd13cf 100644
--- a/tools/lib/bpf/hashmap.h
+++ b/tools/lib/bpf/hashmap.h
@@ -15,6 +15,9 @@
 static inline size_t hash_bits(size_t h, int bits)
 {
 	/* shuffle bits and return requested number of upper bits */
+	if (bits == 0)
+		return 0;
+
 #if (__SIZEOF_SIZE_T__ == __SIZEOF_LONG_LONG__)
 	/* LP64 case */
 	return (h * 11400714819323198485llu) >> (__SIZEOF_LONG_LONG__ * 8 - bits);
@@ -174,17 +177,17 @@ bool hashmap__find(const struct hashmap *map, const void *key, void **value);
  * @key: key to iterate entries for
  */
 #define hashmap__for_each_key_entry(map, cur, _key)			    \
-	for (cur = ({ size_t bkt = hash_bits(map->hash_fn((_key), map->ctx),\
-					     map->cap_bits);		    \
-		     map->buckets ? map->buckets[bkt] : NULL; });	    \
+	for (cur = map->buckets						    \
+		     ? map->buckets[hash_bits(map->hash_fn((_key), map->ctx), map->cap_bits)] \
+		     : NULL;						    \
 	     cur;							    \
 	     cur = cur->next)						    \
 		if (map->equal_fn(cur->key, (_key), map->ctx))
 
 #define hashmap__for_each_key_entry_safe(map, cur, tmp, _key)		    \
-	for (cur = ({ size_t bkt = hash_bits(map->hash_fn((_key), map->ctx),\
-					     map->cap_bits);		    \
-		     cur = map->buckets ? map->buckets[bkt] : NULL; });	    \
+	for (cur = map->buckets						    \
+		     ? map->buckets[hash_bits(map->hash_fn((_key), map->ctx), map->cap_bits)] \
+		     : NULL;						    \
 	     cur && ({ tmp = cur->next; true; });			    \
 	     cur = tmp)							    \
 		if (map->equal_fn(cur->key, (_key), map->ctx))
diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c
index e3c98c007825..9bc537d0b92d 100644
--- a/tools/lib/bpf/xsk.c
+++ b/tools/lib/bpf/xsk.c
@@ -891,13 +891,16 @@ int xsk_umem__delete(struct xsk_umem *umem)
 void xsk_socket__delete(struct xsk_socket *xsk)
 {
 	size_t desc_sz = sizeof(struct xdp_desc);
-	struct xsk_ctx *ctx = xsk->ctx;
 	struct xdp_mmap_offsets off;
+	struct xsk_umem *umem;
+	struct xsk_ctx *ctx;
 	int err;
 
 	if (!xsk)
 		return;
 
+	ctx = xsk->ctx;
+	umem = ctx->umem;
 	if (ctx->prog_fd != -1) {
 		xsk_delete_bpf_maps(xsk);
 		close(ctx->prog_fd);
@@ -917,11 +920,11 @@ void xsk_socket__delete(struct xsk_socket *xsk)
 
 	xsk_put_ctx(ctx);
 
-	ctx->umem->refcount--;
+	umem->refcount--;
 	/* Do not close an fd that also has an associated umem connected
 	 * to it.
 	 */
-	if (xsk->fd != ctx->umem->fd)
+	if (xsk->fd != umem->fd)
 		close(xsk->fd);
 	free(xsk);
 }
diff --git a/tools/testing/selftests/bpf/prog_tests/map_init.c b/tools/testing/selftests/bpf/prog_tests/map_init.c
new file mode 100644
index 000000000000..14a31109dd0e
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/map_init.c
@@ -0,0 +1,214 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2020 Tessares SA <http://www.tessares.net> */
+
+#include <test_progs.h>
+#include "test_map_init.skel.h"
+
+#define TEST_VALUE 0x1234
+#define FILL_VALUE 0xdeadbeef
+
+static int nr_cpus;
+static int duration;
+
+typedef unsigned long long map_key_t;
+typedef unsigned long long map_value_t;
+typedef struct {
+	map_value_t v; /* padding */
+} __bpf_percpu_val_align pcpu_map_value_t;
+
+
+static int map_populate(int map_fd, int num)
+{
+	pcpu_map_value_t value[nr_cpus];
+	int i, err;
+	map_key_t key;
+
+	for (i = 0; i < nr_cpus; i++)
+		bpf_percpu(value, i) = FILL_VALUE;
+
+	for (key = 1; key <= num; key++) {
+		err = bpf_map_update_elem(map_fd, &key, value, BPF_NOEXIST);
+		if (!ASSERT_OK(err, "bpf_map_update_elem"))
+			return -1;
+	}
+
+	return 0;
+}
+
+static struct test_map_init *setup(enum bpf_map_type map_type, int map_sz,
+			    int *map_fd, int populate)
+{
+	struct test_map_init *skel;
+	int err;
+
+	skel = test_map_init__open();
+	if (!ASSERT_OK_PTR(skel, "skel_open"))
+		return NULL;
+
+	err = bpf_map__set_type(skel->maps.hashmap1, map_type);
+	if (!ASSERT_OK(err, "bpf_map__set_type"))
+		goto error;
+
+	err = bpf_map__set_max_entries(skel->maps.hashmap1, map_sz);
+	if (!ASSERT_OK(err, "bpf_map__set_max_entries"))
+		goto error;
+
+	err = test_map_init__load(skel);
+	if (!ASSERT_OK(err, "skel_load"))
+		goto error;
+
+	*map_fd = bpf_map__fd(skel->maps.hashmap1);
+	if (CHECK(*map_fd < 0, "bpf_map__fd", "failed\n"))
+		goto error;
+
+	err = map_populate(*map_fd, populate);
+	if (!ASSERT_OK(err, "map_populate"))
+		goto error_map;
+
+	return skel;
+
+error_map:
+	close(*map_fd);
+error:
+	test_map_init__destroy(skel);
+	return NULL;
+}
+
+/* executes bpf program that updates map with key, value */
+static int prog_run_insert_elem(struct test_map_init *skel, map_key_t key,
+				map_value_t value)
+{
+	struct test_map_init__bss *bss;
+
+	bss = skel->bss;
+
+	bss->inKey = key;
+	bss->inValue = value;
+	bss->inPid = getpid();
+
+	if (!ASSERT_OK(test_map_init__attach(skel), "skel_attach"))
+		return -1;
+
+	/* Let tracepoint trigger */
+	syscall(__NR_getpgid);
+
+	test_map_init__detach(skel);
+
+	return 0;
+}
+
+static int check_values_one_cpu(pcpu_map_value_t *value, map_value_t expected)
+{
+	int i, nzCnt = 0;
+	map_value_t val;
+
+	for (i = 0; i < nr_cpus; i++) {
+		val = bpf_percpu(value, i);
+		if (val) {
+			if (CHECK(val != expected, "map value",
+				  "unexpected for cpu %d: 0x%llx\n", i, val))
+				return -1;
+			nzCnt++;
+		}
+	}
+
+	if (CHECK(nzCnt != 1, "map value", "set for %d CPUs instead of 1!\n",
+		  nzCnt))
+		return -1;
+
+	return 0;
+}
+
+/* Add key=1 elem with values set for all CPUs
+ * Delete elem key=1
+ * Run bpf prog that inserts new key=1 elem with value=0x1234
+ *   (bpf prog can only set value for current CPU)
+ * Lookup Key=1 and check value is as expected for all CPUs:
+ *   value set by bpf prog for one CPU, 0 for all others
+ */
+static void test_pcpu_map_init(void)
+{
+	pcpu_map_value_t value[nr_cpus];
+	struct test_map_init *skel;
+	int map_fd, err;
+	map_key_t key;
+
+	/* max 1 elem in map so insertion is forced to reuse freed entry */
+	skel = setup(BPF_MAP_TYPE_PERCPU_HASH, 1, &map_fd, 1);
+	if (!ASSERT_OK_PTR(skel, "prog_setup"))
+		return;
+
+	/* delete element so the entry can be re-used*/
+	key = 1;
+	err = bpf_map_delete_elem(map_fd, &key);
+	if (!ASSERT_OK(err, "bpf_map_delete_elem"))
+		goto cleanup;
+
+	/* run bpf prog that inserts new elem, re-using the slot just freed */
+	err = prog_run_insert_elem(skel, key, TEST_VALUE);
+	if (!ASSERT_OK(err, "prog_run_insert_elem"))
+		goto cleanup;
+
+	/* check that key=1 was re-created by bpf prog */
+	err = bpf_map_lookup_elem(map_fd, &key, value);
+	if (!ASSERT_OK(err, "bpf_map_lookup_elem"))
+		goto cleanup;
+
+	/* and has expected values */
+	check_values_one_cpu(value, TEST_VALUE);
+
+cleanup:
+	test_map_init__destroy(skel);
+}
+
+/* Add key=1 and key=2 elems with values set for all CPUs
+ * Run bpf prog that inserts new key=3 elem
+ *   (only for current cpu; other cpus should have initial value = 0)
+ * Lookup Key=1 and check value is as expected for all CPUs
+ */
+static void test_pcpu_lru_map_init(void)
+{
+	pcpu_map_value_t value[nr_cpus];
+	struct test_map_init *skel;
+	int map_fd, err;
+	map_key_t key;
+
+	/* Set up LRU map with 2 elements, values filled for all CPUs.
+	 * With these 2 elements, the LRU map is full
+	 */
+	skel = setup(BPF_MAP_TYPE_LRU_PERCPU_HASH, 2, &map_fd, 2);
+	if (!ASSERT_OK_PTR(skel, "prog_setup"))
+		return;
+
+	/* run bpf prog that inserts new key=3 element, re-using LRU slot */
+	key = 3;
+	err = prog_run_insert_elem(skel, key, TEST_VALUE);
+	if (!ASSERT_OK(err, "prog_run_insert_elem"))
+		goto cleanup;
+
+	/* check that key=3 replaced one of earlier elements */
+	err = bpf_map_lookup_elem(map_fd, &key, value);
+	if (!ASSERT_OK(err, "bpf_map_lookup_elem"))
+		goto cleanup;
+
+	/* and has expected values */
+	check_values_one_cpu(value, TEST_VALUE);
+
+cleanup:
+	test_map_init__destroy(skel);
+}
+
+void test_map_init(void)
+{
+	nr_cpus = bpf_num_possible_cpus();
+	if (nr_cpus <= 1) {
+		printf("%s:SKIP: >1 cpu needed for this test\n", __func__);
+		test__skip();
+		return;
+	}
+
+	if (test__start_subtest("pcpu_map_init"))
+		test_pcpu_map_init();
+	if (test__start_subtest("pcpu_lru_map_init"))
+		test_pcpu_lru_map_init();
+}
diff --git a/tools/testing/selftests/bpf/progs/profiler.inc.h b/tools/testing/selftests/bpf/progs/profiler.inc.h
index 00578311a423..30982a7e4d0f 100644
--- a/tools/testing/selftests/bpf/progs/profiler.inc.h
+++ b/tools/testing/selftests/bpf/progs/profiler.inc.h
@@ -243,7 +243,10 @@ static ino_t get_inode_from_kernfs(struct kernfs_node* node)
 	}
 }
 
-int pids_cgrp_id = 1;
+extern bool CONFIG_CGROUP_PIDS __kconfig __weak;
+enum cgroup_subsys_id___local {
+	pids_cgrp_id___local = 123, /* value doesn't matter */
+};
 
 static INLINE void* populate_cgroup_info(struct cgroup_data_t* cgroup_data,
 					 struct task_struct* task,
@@ -253,7 +256,9 @@ static INLINE void* populate_cgroup_info(struct cgroup_data_t* cgroup_data,
 		BPF_CORE_READ(task, nsproxy, cgroup_ns, root_cset, dfl_cgrp, kn);
 	struct kernfs_node* proc_kernfs = BPF_CORE_READ(task, cgroups, dfl_cgrp, kn);
 
-	if (ENABLE_CGROUP_V1_RESOLVER) {
+	if (ENABLE_CGROUP_V1_RESOLVER && CONFIG_CGROUP_PIDS) {
+		int cgrp_id = bpf_core_enum_value(enum cgroup_subsys_id___local,
+						  pids_cgrp_id___local);
 #ifdef UNROLL
 #pragma unroll
 #endif
@@ -262,7 +267,7 @@ static INLINE void* populate_cgroup_info(struct cgroup_data_t* cgroup_data,
 				BPF_CORE_READ(task, cgroups, subsys[i]);
 			if (subsys != NULL) {
 				int subsys_id = BPF_CORE_READ(subsys, ss, id);
-				if (subsys_id == pids_cgrp_id) {
+				if (subsys_id == cgrp_id) {
 					proc_kernfs = BPF_CORE_READ(subsys, cgroup, kn);
 					root_kernfs = BPF_CORE_READ(subsys, ss, root, kf_root, kn);
 					break;
diff --git a/tools/testing/selftests/bpf/progs/test_map_init.c b/tools/testing/selftests/bpf/progs/test_map_init.c
new file mode 100644
index 000000000000..c89d28ead673
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_map_init.c
@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2020 Tessares SA <http://www.tessares.net> */
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+
+__u64 inKey = 0;
+__u64 inValue = 0;
+__u32 inPid = 0;
+
+struct {
+	__uint(type, BPF_MAP_TYPE_PERCPU_HASH);
+	__uint(max_entries, 2);
+	__type(key, __u64);
+	__type(value, __u64);
+} hashmap1 SEC(".maps");
+
+
+SEC("tp/syscalls/sys_enter_getpgid")
+int sysenter_getpgid(const void *ctx)
+{
+	/* Just do it for once, when called from our own test prog. This
+	 * ensures the map value is only updated for a single CPU.
+	 */
+	int cur_pid = bpf_get_current_pid_tgid() >> 32;
+
+	if (cur_pid == inPid)
+		bpf_map_update_elem(&hashmap1, &inKey, &inValue, BPF_NOEXIST);
+
+	return 0;
+}
+
+char _license[] SEC("license") = "GPL";