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

Daniel Borkmann says:

====================
pull-request: bpf-next 2022-03-04

We've added 32 non-merge commits during the last 14 day(s) which contain
a total of 59 files changed, 1038 insertions(+), 473 deletions(-).

The main changes are:

1) Optimize BPF stackmap's build_id retrieval by caching last valid build_id,
   as consecutive stack frames are likely to be in the same VMA and therefore
   have the same build id, from Hao Luo.

2) Several improvements to arm64 BPF JIT, that is, support for JITing
   the atomic[64]_fetch_add, atomic[64]_[fetch_]{and,or,xor} and lastly
   atomic[64]_{xchg|cmpxchg}. Also fix the BTF line info dump for JITed
   programs, from Hou Tao.

3) Optimize generic BPF map batch deletion by only enforcing synchronize_rcu()
   barrier once upon return to user space, from Eric Dumazet.

4) For kernel build parse DWARF and generate BTF through pahole with enabled
   multithreading, from Kui-Feng Lee.

5) BPF verifier usability improvements by making log info more concise and
   replacing inv with scalar type name, from Mykola Lysenko.

6) Two follow-up fixes for BPF prog JIT pack allocator, from Song Liu.

7) Add a new Kconfig to allow for loading kernel modules with non-matching
   BTF type info; their BTF info is then removed on load, from Connor O'Brien.

8) Remove reallocarray() usage from bpftool and switch to libbpf_reallocarray()
   in order to fix compilation errors for older glibc, from Mauricio Vásquez.

9) Fix libbpf to error on conflicting name in BTF when type declaration
   appears before the definition, from Xu Kuohai.

10) Fix issue in BPF preload for in-kernel light skeleton where loaded BPF
    program fds prevent init process from setting up fd 0-2, from Yucong Sun.

11) Fix libbpf reuse of pinned perf RB map when max_entries is auto-determined
    by libbpf, from Stijn Tintel.

12) Several cleanups for libbpf and a fix to enforce perf RB map #pages to be
    non-zero, from Yuntao Wang.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (32 commits)
  bpf: Small BPF verifier log improvements
  libbpf: Add a check to ensure that page_cnt is non-zero
  bpf, x86: Set header->size properly before freeing it
  x86: Disable HAVE_ARCH_HUGE_VMALLOC on 32-bit x86
  bpf, test_run: Fix overflow in XDP frags bpf_test_finish
  selftests/bpf: Update btf_dump case for conflicting names
  libbpf: Skip forward declaration when counting duplicated type names
  bpf: Add some description about BPF_JIT_ALWAYS_ON in Kconfig
  bpf, docs: Add a missing colon in verifier.rst
  bpf: Cache the last valid build_id
  libbpf: Fix BPF_MAP_TYPE_PERF_EVENT_ARRAY auto-pinning
  bpf, selftests: Use raw_tp program for atomic test
  bpf, arm64: Support more atomic operations
  bpftool: Remove redundant slashes
  bpf: Add config to allow loading modules with BTF mismatches
  bpf, arm64: Feed byte-offset into bpf line info
  bpf, arm64: Call build_prologue() first in first JIT pass
  bpf: Fix issue with bpf preload module taking over stdout/stdin of kernel.
  bpftool: Bpf skeletons assert type sizes
  bpf: Cleanup comments
  ...
====================

Link: https://lore.kernel.org/r/20220304164313.31675-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 30 insertions, 26 deletions

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index ad43b6ce825e..81bf01d67671 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -1374,22 +1374,20 @@ static bool bpf_map_type__is_map_in_map(enum bpf_map_type type)
 
 static int find_elf_sec_sz(const struct bpf_object *obj, const char *name, __u32 *size)
 {
-	int ret = -ENOENT;
 	Elf_Data *data;
 	Elf_Scn *scn;
 
-	*size = 0;
 	if (!name)
 		return -EINVAL;
 
 	scn = elf_sec_by_name(obj, name);
 	data = elf_sec_data(obj, scn);
 	if (data) {
-		ret = 0; /* found it */
 		*size = data->d_size;
+		return 0; /* found it */
 	}
 
-	return *size ? 0 : ret;
+	return -ENOENT;
 }
 
 static int find_elf_var_offset(const struct bpf_object *obj, const char *name, __u32 *off)
@@ -2795,7 +2793,7 @@ static int btf_fixup_datasec(struct bpf_object *obj, struct btf *btf,
 		goto sort_vars;
 
 	ret = find_elf_sec_sz(obj, name, &size);
-	if (ret || !size || (t->size && t->size != size)) {
+	if (ret || !size) {
 		pr_debug("Invalid size for section %s: %u bytes\n", name, size);
 		return -ENOENT;
 	}
@@ -4861,7 +4859,6 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, b
 	LIBBPF_OPTS(bpf_map_create_opts, create_attr);
 	struct bpf_map_def *def = &map->def;
 	const char *map_name = NULL;
-	__u32 max_entries;
 	int err = 0;
 
 	if (kernel_supports(obj, FEAT_PROG_NAME))
@@ -4871,21 +4868,6 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, b
 	create_attr.numa_node = map->numa_node;
 	create_attr.map_extra = map->map_extra;
 
-	if (def->type == BPF_MAP_TYPE_PERF_EVENT_ARRAY && !def->max_entries) {
-		int nr_cpus;
-
-		nr_cpus = libbpf_num_possible_cpus();
-		if (nr_cpus < 0) {
-			pr_warn("map '%s': failed to determine number of system CPUs: %d\n",
-				map->name, nr_cpus);
-			return nr_cpus;
-		}
-		pr_debug("map '%s': setting size to %d\n", map->name, nr_cpus);
-		max_entries = nr_cpus;
-	} else {
-		max_entries = def->max_entries;
-	}
-
 	if (bpf_map__is_struct_ops(map))
 		create_attr.btf_vmlinux_value_type_id = map->btf_vmlinux_value_type_id;
 
@@ -4935,7 +4917,7 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, b
 
 	if (obj->gen_loader) {
 		bpf_gen__map_create(obj->gen_loader, def->type, map_name,
-				    def->key_size, def->value_size, max_entries,
+				    def->key_size, def->value_size, def->max_entries,
 				    &create_attr, is_inner ? -1 : map - obj->maps);
 		/* Pretend to have valid FD to pass various fd >= 0 checks.
 		 * This fd == 0 will not be used with any syscall and will be reset to -1 eventually.
@@ -4944,7 +4926,7 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, b
 	} else {
 		map->fd = bpf_map_create(def->type, map_name,
 					 def->key_size, def->value_size,
-					 max_entries, &create_attr);
+					 def->max_entries, &create_attr);
 	}
 	if (map->fd < 0 && (create_attr.btf_key_type_id ||
 			    create_attr.btf_value_type_id)) {
@@ -4961,7 +4943,7 @@ static int bpf_object__create_map(struct bpf_object *obj, struct bpf_map *map, b
 		map->btf_value_type_id = 0;
 		map->fd = bpf_map_create(def->type, map_name,
 					 def->key_size, def->value_size,
-					 max_entries, &create_attr);
+					 def->max_entries, &create_attr);
 	}
 
 	err = map->fd < 0 ? -errno : 0;
@@ -5065,6 +5047,24 @@ static int bpf_object_init_prog_arrays(struct bpf_object *obj)
 	return 0;
 }
 
+static int map_set_def_max_entries(struct bpf_map *map)
+{
+	if (map->def.type == BPF_MAP_TYPE_PERF_EVENT_ARRAY && !map->def.max_entries) {
+		int nr_cpus;
+
+		nr_cpus = libbpf_num_possible_cpus();
+		if (nr_cpus < 0) {
+			pr_warn("map '%s': failed to determine number of system CPUs: %d\n",
+				map->name, nr_cpus);
+			return nr_cpus;
+		}
+		pr_debug("map '%s': setting size to %d\n", map->name, nr_cpus);
+		map->def.max_entries = nr_cpus;
+	}
+
+	return 0;
+}
+
 static int
 bpf_object__create_maps(struct bpf_object *obj)
 {
@@ -5097,6 +5097,10 @@ bpf_object__create_maps(struct bpf_object *obj)
 			continue;
 		}
 
+		err = map_set_def_max_entries(map);
+		if (err)
+			goto err_out;
+
 		retried = false;
 retry:
 		if (map->pin_path) {
@@ -10947,7 +10951,7 @@ struct perf_buffer *perf_buffer__new_raw_v0_6_0(int map_fd, size_t page_cnt,
 {
 	struct perf_buffer_params p = {};
 
-	if (page_cnt == 0 || !attr)
+	if (!attr)
 		return libbpf_err_ptr(-EINVAL);
 
 	if (!OPTS_VALID(opts, perf_buffer_raw_opts))
@@ -10988,7 +10992,7 @@ static struct perf_buffer *__perf_buffer__new(int map_fd, size_t page_cnt,
 	__u32 map_info_len;
 	int err, i, j, n;
 
-	if (page_cnt & (page_cnt - 1)) {
+	if (page_cnt == 0 || (page_cnt & (page_cnt - 1))) {
 		pr_warn("page count should be power of two, but is %zu\n",
 			page_cnt);
 		return ERR_PTR(-EINVAL);