Merge tag 'bpf-next-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Pull bpf updates from Alexei Starovoitov:
 "For this merge window we're splitting BPF pull request into three for
  higher visibility: main changes, res_spin_lock, try_alloc_pages.

  These are the main BPF changes:

   - Add DFA-based live registers analysis to improve verification of
     programs with loops (Eduard Zingerman)

   - Introduce load_acquire and store_release BPF instructions and add
     x86, arm64 JIT support (Peilin Ye)

   - Fix loop detection logic in the verifier (Eduard Zingerman)

   - Drop unnecesary lock in bpf_map_inc_not_zero() (Eric Dumazet)

   - Add kfunc for populating cpumask bits (Emil Tsalapatis)

   - Convert various shell based tests to selftests/bpf/test_progs
     format (Bastien Curutchet)

   - Allow passing referenced kptrs into struct_ops callbacks (Amery
     Hung)

   - Add a flag to LSM bpf hook to facilitate bpf program signing
     (Blaise Boscaccy)

   - Track arena arguments in kfuncs (Ihor Solodrai)

   - Add copy_remote_vm_str() helper for reading strings from remote VM
     and bpf_copy_from_user_task_str() kfunc (Jordan Rome)

   - Add support for timed may_goto instruction (Kumar Kartikeya
     Dwivedi)

   - Allow bpf_get_netns_cookie() int cgroup_skb programs (Mahe Tardy)

   - Reduce bpf_cgrp_storage_busy false positives when accessing cgroup
     local storage (Martin KaFai Lau)

   - Introduce bpf_dynptr_copy() kfunc (Mykyta Yatsenko)

   - Allow retrieving BTF data with BTF token (Mykyta Yatsenko)

   - Add BPF kfuncs to set and get xattrs with 'security.bpf.' prefix
     (Song Liu)

   - Reject attaching programs to noreturn functions (Yafang Shao)

   - Introduce pre-order traversal of cgroup bpf programs (Yonghong
     Song)"

* tag 'bpf-next-6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (186 commits)
  selftests/bpf: Add selftests for load-acquire/store-release when register number is invalid
  bpf: Fix out-of-bounds read in check_atomic_load/store()
  libbpf: Add namespace for errstr making it libbpf_errstr
  bpf: Add struct_ops context information to struct bpf_prog_aux
  selftests/bpf: Sanitize pointer prior fclose()
  selftests/bpf: Migrate test_xdp_vlan.sh into test_progs
  selftests/bpf: test_xdp_vlan: Rename BPF sections
  bpf: clarify a misleading verifier error message
  selftests/bpf: Add selftest for attaching fexit to __noreturn functions
  bpf: Reject attaching fexit/fmod_ret to __noreturn functions
  bpf: Only fails the busy counter check in bpf_cgrp_storage_get if it creates storage
  bpf: Make perf_event_read_output accessible in all program types.
  bpftool: Using the right format specifiers
  bpftool: Add -Wformat-signedness flag to detect format errors
  selftests/bpf: Test freplace from user namespace
  libbpf: Pass BPF token from find_prog_btf_id to BPF_BTF_GET_FD_BY_ID
  bpf: Return prog btf_id without capable check
  bpf: BPF token support for BPF_BTF_GET_FD_BY_ID
  bpf, x86: Fix objtool warning for timed may_goto
  bpf: Check map->record at the beginning of check_and_free_fields()
  ...

1 files changed, 25 insertions, 8 deletions

diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index 46e5db65dbc8..84f58f3d028a 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -369,7 +369,7 @@ static struct bpf_prog *prog_list_prog(struct bpf_prog_list *pl)
 /* count number of elements in the list.
  * it's slow but the list cannot be long
  */
-static u32 prog_list_length(struct hlist_head *head)
+static u32 prog_list_length(struct hlist_head *head, int *preorder_cnt)
 {
 	struct bpf_prog_list *pl;
 	u32 cnt = 0;
@@ -377,6 +377,8 @@ static u32 prog_list_length(struct hlist_head *head)
 	hlist_for_each_entry(pl, head, node) {
 		if (!prog_list_prog(pl))
 			continue;
+		if (preorder_cnt && (pl->flags & BPF_F_PREORDER))
+			(*preorder_cnt)++;
 		cnt++;
 	}
 	return cnt;
@@ -400,7 +402,7 @@ static bool hierarchy_allows_attach(struct cgroup *cgrp,
 
 		if (flags & BPF_F_ALLOW_MULTI)
 			return true;
-		cnt = prog_list_length(&p->bpf.progs[atype]);
+		cnt = prog_list_length(&p->bpf.progs[atype], NULL);
 		WARN_ON_ONCE(cnt > 1);
 		if (cnt == 1)
 			return !!(flags & BPF_F_ALLOW_OVERRIDE);
@@ -423,12 +425,12 @@ static int compute_effective_progs(struct cgroup *cgrp,
 	struct bpf_prog_array *progs;
 	struct bpf_prog_list *pl;
 	struct cgroup *p = cgrp;
-	int cnt = 0;
+	int i, j, cnt = 0, preorder_cnt = 0, fstart, bstart, init_bstart;
 
 	/* count number of effective programs by walking parents */
 	do {
 		if (cnt == 0 || (p->bpf.flags[atype] & BPF_F_ALLOW_MULTI))
-			cnt += prog_list_length(&p->bpf.progs[atype]);
+			cnt += prog_list_length(&p->bpf.progs[atype], &preorder_cnt);
 		p = cgroup_parent(p);
 	} while (p);
 
@@ -439,20 +441,34 @@ static int compute_effective_progs(struct cgroup *cgrp,
 	/* populate the array with effective progs */
 	cnt = 0;
 	p = cgrp;
+	fstart = preorder_cnt;
+	bstart = preorder_cnt - 1;
 	do {
 		if (cnt > 0 && !(p->bpf.flags[atype] & BPF_F_ALLOW_MULTI))
 			continue;
 
+		init_bstart = bstart;
 		hlist_for_each_entry(pl, &p->bpf.progs[atype], node) {
 			if (!prog_list_prog(pl))
 				continue;
 
-			item = &progs->items[cnt];
+			if (pl->flags & BPF_F_PREORDER) {
+				item = &progs->items[bstart];
+				bstart--;
+			} else {
+				item = &progs->items[fstart];
+				fstart++;
+			}
 			item->prog = prog_list_prog(pl);
 			bpf_cgroup_storages_assign(item->cgroup_storage,
 						   pl->storage);
 			cnt++;
 		}
+
+		/* reverse pre-ordering progs at this cgroup level */
+		for (i = bstart + 1, j = init_bstart; i < j; i++, j--)
+			swap(progs->items[i], progs->items[j]);
+
 	} while ((p = cgroup_parent(p)));
 
 	*array = progs;
@@ -663,7 +679,7 @@ static int __cgroup_bpf_attach(struct cgroup *cgrp,
 		 */
 		return -EPERM;
 
-	if (prog_list_length(progs) >= BPF_CGROUP_MAX_PROGS)
+	if (prog_list_length(progs, NULL) >= BPF_CGROUP_MAX_PROGS)
 		return -E2BIG;
 
 	pl = find_attach_entry(progs, prog, link, replace_prog,
@@ -698,6 +714,7 @@ static int __cgroup_bpf_attach(struct cgroup *cgrp,
 
 	pl->prog = prog;
 	pl->link = link;
+	pl->flags = flags;
 	bpf_cgroup_storages_assign(pl->storage, storage);
 	cgrp->bpf.flags[atype] = saved_flags;
 
@@ -1073,7 +1090,7 @@ static int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr,
 							      lockdep_is_held(&cgroup_mutex));
 			total_cnt += bpf_prog_array_length(effective);
 		} else {
-			total_cnt += prog_list_length(&cgrp->bpf.progs[atype]);
+			total_cnt += prog_list_length(&cgrp->bpf.progs[atype], NULL);
 		}
 	}
 
@@ -1105,7 +1122,7 @@ static int __cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr,
 			u32 id;
 
 			progs = &cgrp->bpf.progs[atype];
-			cnt = min_t(int, prog_list_length(progs), total_cnt);
+			cnt = min_t(int, prog_list_length(progs, NULL), total_cnt);
 			i = 0;
 			hlist_for_each_entry(pl, progs, node) {
 				prog = prog_list_prog(pl);