linux/kernel/bpf
Martin KaFai Lau 2ddef1783c bpf: Allow refcounted bpf_rb_node used in bpf_rbtree_{remove,left,right}
The bpf_rbtree_{remove,left,right} requires the root's lock to be held.
They also check the node_internal->owner is still owned by that root
before proceeding, so it is safe to allow refcounted bpf_rb_node
pointer to be used in these kfuncs.

In a bpf fq implementation which is much closer to the kernel fq,
https://lore.kernel.org/bpf/20250418224652.105998-13-martin.lau@linux.dev/,
a networking flow (allocated by bpf_obj_new) can be added to two different
rbtrees. There are cases that the flow is searched from one rbtree,
held the refcount of the flow, and then removed from another rbtree:

struct fq_flow {
	struct bpf_rb_node	fq_node;
	struct bpf_rb_node	rate_node;
	struct bpf_refcount	refcount;
	unsigned long		sk_long;
};

int bpf_fq_enqueue(...)
{
	/* ... */

	bpf_spin_lock(&root->lock);
	while (can_loop) {
		/* ... */
		if (!p)
			break;
		gc_f = bpf_rb_entry(p, struct fq_flow, fq_node);
		if (gc_f->sk_long == sk_long) {
			f = bpf_refcount_acquire(gc_f);
			break;
		}
		/* ... */
	}
	bpf_spin_unlock(&root->lock);

	if (f) {
		bpf_spin_lock(&q->lock);
		bpf_rbtree_remove(&q->delayed, &f->rate_node);
		bpf_spin_unlock(&q->lock);
	}
}

bpf_rbtree_{left,right} do not need this change but are relaxed together
with bpf_rbtree_remove instead of adding extra verifier logic
to exclude these kfuncs.

To avoid bi-sect failure, this patch also changes the selftests together.

The "rbtree_api_remove_unadded_node" is not expecting verifier's error.
The test now expects bpf_rbtree_remove(&groot, &m->node) to return NULL.
The test uses __retval(0) to ensure this NULL return value.

Some of the "only take non-owning..." failure messages are changed also.

Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20250506015857.817950-5-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-05-06 10:21:05 -07:00
..
preload bpf: Add namespace to BPF internal symbols 2025-04-25 09:21:23 -07:00
arena.c bpf_try_alloc_pages 2025-03-30 13:45:28 -07:00
arraymap.c bpf: Remove migrate_{disable|enable} in ->map_for_each_callback 2025-01-08 18:06:35 -08:00
bloom_filter.c bpf: Check bloom filter map value size 2024-03-27 09:56:17 -07:00
bpf_cgrp_storage.c bpf: Only fails the busy counter check in bpf_cgrp_storage_get if it creates storage 2025-03-18 19:05:46 -07:00
bpf_inode_storage.c bpf: Disable migration when destroying inode storage 2025-01-08 18:06:36 -08:00
bpf_iter.c bpf: Make every prog keep a copy of ctx_arg_info 2025-02-17 18:47:27 -08:00
bpf_local_storage.c bpf: Remove migrate_{disable|enable} from bpf_selem_free() 2025-01-08 18:06:37 -08:00
bpf_lru_list.c
bpf_lru_list.h
bpf_lsm.c bpf: lsm: Add two more sleepable hooks 2025-02-13 19:35:31 -08:00
bpf_struct_ops.c bpf: Allow struct_ops prog to return referenced kptr 2025-02-17 18:47:27 -08:00
bpf_task_storage.c bpf: Remove migrate_{disable|enable} from bpf_task_storage_lock helpers 2025-01-08 18:06:36 -08:00
btf.c bpf: Replace offsetof() with struct_size() 2025-05-05 14:21:46 -07:00
btf_iter.c bpf: Remove custom build rule 2024-08-30 08:55:26 -07:00
btf_relocate.c bpf: Remove custom build rule 2024-08-30 08:55:26 -07:00
cgroup.c bpf: Allow pre-ordering for bpf cgroup progs 2025-03-15 11:48:25 -07:00
cgroup_iter.c
core.c bpf: Allow XDP dev-bound programs to perform XDP_REDIRECT into maps 2025-05-01 12:54:06 -07:00
cpumap.c bpf: cpumap: switch to napi_skb_cache_get_bulk() 2025-02-27 14:03:39 +01:00
cpumask.c bpf: fix missing kdoc string fields in cpumask.c 2025-03-15 11:48:57 -07:00
crypto.c bpf: crypto: make state and IV dynptr nullable 2024-06-13 16:33:04 -07:00
devmap.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2024-12-12 14:19:05 -08:00
disasm.c bpftool: Using the right format specifiers 2025-03-17 13:50:56 -07:00
disasm.h
dispatcher.c bpf: Add kernel symbol for struct_ops trampoline 2024-11-12 17:13:46 -08:00
hashtab.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf after rc4 2025-04-28 08:40:45 -07:00
helpers.c bpf: Add bpf_rbtree_{root,left,right} kfunc 2025-05-06 10:21:05 -07:00
inode.c Change inode_operations.mkdir to return struct dentry * 2025-02-27 20:00:17 +01:00
Kconfig bpf: remove CONFIG_BPF_JIT dependency on CONFIG_MODULES of 2024-05-14 00:36:29 -07:00
kmem_cache_iter.c bpf: Add open coded version of kmem_cache iterator 2024-11-01 11:08:32 -07:00
link_iter.c
local_storage.c bpf: Replace 8 seq_puts() calls by seq_putc() calls 2024-07-29 12:53:00 -07:00
log.c bpf: Introduce support for bpf_local_irq_{save,restore} 2024-12-04 08:38:29 -08:00
lpm_trie.c bpf: Convert lpm_trie.c to rqspinlock 2025-03-19 08:03:05 -07:00
Makefile rqspinlock: Add entry to Makefile, MAINTAINERS 2025-03-19 08:03:05 -07:00
map_in_map.c bpf: switch maps to CLASS(fd, ...) 2024-08-13 15:58:17 -07:00
map_in_map.h
map_iter.c bpf: treewide: Annotate BPF kfuncs in BTF 2024-01-31 20:40:56 -08:00
memalloc.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf 2024-11-13 12:52:51 -08:00
mmap_unlock_work.h
mprog.c
net_namespace.c
offload.c net: move misc netdev_lock flavors to a separate header 2025-03-08 09:06:50 -08:00
percpu_freelist.c bpf: Convert percpu_freelist.c to rqspinlock 2025-03-19 08:03:05 -07:00
percpu_freelist.h bpf: Convert percpu_freelist.c to rqspinlock 2025-03-19 08:03:05 -07:00
prog_iter.c
queue_stack_maps.c bpf: Convert queue_stack map to rqspinlock 2025-04-10 12:51:10 -07:00
range_tree.c bpf: Disable migration before calling ops->map_free() 2025-01-08 18:06:36 -08:00
range_tree.h bpf: Introduce range_tree data structure and use it in bpf arena 2024-11-13 13:52:45 -08:00
relo_core.c bpf: Remove custom build rule 2024-08-30 08:55:26 -07:00
reuseport_array.c bpf: Use sockfd_put() helper 2024-08-30 08:57:47 -07:00
ringbuf.c bpf: Convert ringbuf map to rqspinlock 2025-04-11 10:28:26 -07:00
rqspinlock.c bpf: Use architecture provided res_smp_cond_load_acquire 2025-04-10 12:47:07 -07:00
rqspinlock.h rqspinlock: Protect waiters in queue from stalls 2025-03-19 08:03:05 -07:00
stackmap.c bpf: wire up sleepable bpf_get_stack() and bpf_get_task_stack() helpers 2024-09-11 09:58:31 -07:00
syscall.c bpf: Replace offsetof() with struct_size() 2025-05-01 10:37:35 -07:00
sysfs_btf.c btf: Switch vmlinux BTF attribute to sysfs_bin_attr_simple_read() 2025-01-09 10:44:06 +01:00
task_iter.c vfs-6.13.file 2024-11-18 10:30:29 -08:00
tcx.c
tnum.c
token.c remove pointless includes of <linux/fdtable.h> 2024-10-07 13:34:41 -04:00
trampoline.c bpf: Add kernel symbol for struct_ops trampoline 2024-11-12 17:13:46 -08:00
verifier.c bpf: Allow refcounted bpf_rb_node used in bpf_rbtree_{remove,left,right} 2025-05-06 10:21:05 -07:00