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

Daniel Borkmann says:

====================
bpf-next 2022-07-22

We've added 73 non-merge commits during the last 12 day(s) which contain
a total of 88 files changed, 3458 insertions(+), 860 deletions(-).

The main changes are:

1) Implement BPF trampoline for arm64 JIT, from Xu Kuohai.

2) Add ksyscall/kretsyscall section support to libbpf to simplify tracing kernel
   syscalls through kprobe mechanism, from Andrii Nakryiko.

3) Allow for livepatch (KLP) and BPF trampolines to attach to the same kernel
   function, from Song Liu & Jiri Olsa.

4) Add new kfunc infrastructure for netfilter's CT e.g. to insert and change
   entries, from Kumar Kartikeya Dwivedi & Lorenzo Bianconi.

5) Add a ksym BPF iterator to allow for more flexible and efficient interactions
   with kernel symbols, from Alan Maguire.

6) Bug fixes in libbpf e.g. for uprobe binary path resolution, from Dan Carpenter.

7) Fix BPF subprog function names in stack traces, from Alexei Starovoitov.

8) libbpf support for writing custom perf event readers, from Jon Doron.

9) Switch to use SPDX tag for BPF helper man page, from Alejandro Colomar.

10) Fix xsk send-only sockets when in busy poll mode, from Maciej Fijalkowski.

11) Reparent BPF maps and their charging on memcg offlining, from Roman Gushchin.

12) Multiple follow-up fixes around BPF lsm cgroup infra, from Stanislav Fomichev.

13) Use bootstrap version of bpftool where possible to speed up builds, from Pu Lehui.

14) Cleanup BPF verifier's check_func_arg() handling, from Joanne Koong.

15) Make non-prealloced BPF map allocations low priority to play better with
    memcg limits, from Yafang Shao.

16) Fix BPF test runner to reject zero-length data for skbs, from Zhengchao Shao.

17) Various smaller cleanups and improvements all over the place.

* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (73 commits)
  bpf: Simplify bpf_prog_pack_[size|mask]
  bpf: Support bpf_trampoline on functions with IPMODIFY (e.g. livepatch)
  bpf, x64: Allow to use caller address from stack
  ftrace: Allow IPMODIFY and DIRECT ops on the same function
  ftrace: Add modify_ftrace_direct_multi_nolock
  bpf/selftests: Fix couldn't retrieve pinned program in xdp veth test
  bpf: Fix build error in case of !CONFIG_DEBUG_INFO_BTF
  selftests/bpf: Fix test_verifier failed test in unprivileged mode
  selftests/bpf: Add negative tests for new nf_conntrack kfuncs
  selftests/bpf: Add tests for new nf_conntrack kfuncs
  selftests/bpf: Add verifier tests for trusted kfunc args
  net: netfilter: Add kfuncs to set and change CT status
  net: netfilter: Add kfuncs to set and change CT timeout
  net: netfilter: Add kfuncs to allocate and insert CT
  net: netfilter: Deduplicate code in bpf_{xdp,skb}_ct_lookup
  bpf: Add documentation for kfuncs
  bpf: Add support for forcing kfunc args to be trusted
  bpf: Switch to new kfunc flags infrastructure
  tools/resolve_btfids: Add support for 8-byte BTF sets
  bpf: Introduce 8-byte BTF set
  ...
====================

Link: https://lore.kernel.org/r/20220722221218.29943-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 28 insertions, 8 deletions

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index ab688d85b2c6..83c7136c5788 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -419,35 +419,53 @@ void bpf_map_free_id(struct bpf_map *map, bool do_idr_lock)
 #ifdef CONFIG_MEMCG_KMEM
 static void bpf_map_save_memcg(struct bpf_map *map)
 {
-	map->memcg = get_mem_cgroup_from_mm(current->mm);
+	/* Currently if a map is created by a process belonging to the root
+	 * memory cgroup, get_obj_cgroup_from_current() will return NULL.
+	 * So we have to check map->objcg for being NULL each time it's
+	 * being used.
+	 */
+	map->objcg = get_obj_cgroup_from_current();
 }
 
 static void bpf_map_release_memcg(struct bpf_map *map)
 {
-	mem_cgroup_put(map->memcg);
+	if (map->objcg)
+		obj_cgroup_put(map->objcg);
+}
+
+static struct mem_cgroup *bpf_map_get_memcg(const struct bpf_map *map)
+{
+	if (map->objcg)
+		return get_mem_cgroup_from_objcg(map->objcg);
+
+	return root_mem_cgroup;
 }
 
 void *bpf_map_kmalloc_node(const struct bpf_map *map, size_t size, gfp_t flags,
 			   int node)
 {
-	struct mem_cgroup *old_memcg;
+	struct mem_cgroup *memcg, *old_memcg;
 	void *ptr;
 
-	old_memcg = set_active_memcg(map->memcg);
+	memcg = bpf_map_get_memcg(map);
+	old_memcg = set_active_memcg(memcg);
 	ptr = kmalloc_node(size, flags | __GFP_ACCOUNT, node);
 	set_active_memcg(old_memcg);
+	mem_cgroup_put(memcg);
 
 	return ptr;
 }
 
 void *bpf_map_kzalloc(const struct bpf_map *map, size_t size, gfp_t flags)
 {
-	struct mem_cgroup *old_memcg;
+	struct mem_cgroup *memcg, *old_memcg;
 	void *ptr;
 
-	old_memcg = set_active_memcg(map->memcg);
+	memcg = bpf_map_get_memcg(map);
+	old_memcg = set_active_memcg(memcg);
 	ptr = kzalloc(size, flags | __GFP_ACCOUNT);
 	set_active_memcg(old_memcg);
+	mem_cgroup_put(memcg);
 
 	return ptr;
 }
@@ -455,12 +473,14 @@ void *bpf_map_kzalloc(const struct bpf_map *map, size_t size, gfp_t flags)
 void __percpu *bpf_map_alloc_percpu(const struct bpf_map *map, size_t size,
 				    size_t align, gfp_t flags)
 {
-	struct mem_cgroup *old_memcg;
+	struct mem_cgroup *memcg, *old_memcg;
 	void __percpu *ptr;
 
-	old_memcg = set_active_memcg(map->memcg);
+	memcg = bpf_map_get_memcg(map);
+	old_memcg = set_active_memcg(memcg);
 	ptr = __alloc_percpu_gfp(size, align, flags | __GFP_ACCOUNT);
 	set_active_memcg(old_memcg);
+	mem_cgroup_put(memcg);
 
 	return ptr;
 }