diff options
| author | Kaitao Cheng <chengkaitao@kylinos.cn> | 2026-02-14 20:40:41 +0800 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2026-02-23 17:37:06 -0800 |
| commit | fb1590448ff7e79e304f9bbe662fc20334038b50 (patch) | |
| tree | cee1470c81ad00f40719b351f9c84696d4eace17 /kernel | |
| parent | 580fa3430b5d164fe8841e99825601d7a85af0d3 (diff) | |
bpf: allow using bpf_kptr_xchg even if the MEM_RCU flag is set
For the following scenario:
struct tree_node {
struct bpf_refcount ref;
struct bpf_rb_node node;
struct node_data __kptr * node_data;
u64 key;
};
This means node_data would have the type PTR_TO_BTF_ID | MEM_ALLOC |
NON_OWN_REF | MEM_RCU.
When traversing an rbtree using bpf_rbtree_left/right, if we need to
use bpf_kptr_xchg to read the __kptr pointer, we still need to follow
the remove-read-add sequence.
This patch allows us to use bpf_kptr_xchg to directly read the __kptr
pointer without any prior operations.
Signed-off-by: Kaitao Cheng <chengkaitao@kylinos.cn>
Signed-off-by: Feng Yang <yangfeng@kylinos.cn>
Link: https://lore.kernel.org/r/20260214124042.62229-5-pilgrimtao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/verifier.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 7426dba5e5d1..1153a828ce8d 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -9311,6 +9311,7 @@ static const struct bpf_reg_types kptr_xchg_dest_types = { PTR_TO_MAP_VALUE, PTR_TO_BTF_ID | MEM_ALLOC, PTR_TO_BTF_ID | MEM_ALLOC | NON_OWN_REF, + PTR_TO_BTF_ID | MEM_ALLOC | NON_OWN_REF | MEM_RCU, } }; static const struct bpf_reg_types dynptr_types = { @@ -9475,6 +9476,7 @@ found: case PTR_TO_BTF_ID | MEM_ALLOC: case PTR_TO_BTF_ID | MEM_PERCPU | MEM_ALLOC: case PTR_TO_BTF_ID | MEM_ALLOC | NON_OWN_REF: + case PTR_TO_BTF_ID | MEM_ALLOC | NON_OWN_REF | MEM_RCU: if (meta->func_id != BPF_FUNC_spin_lock && meta->func_id != BPF_FUNC_spin_unlock && meta->func_id != BPF_FUNC_kptr_xchg) { verifier_bug(env, "unimplemented handling of MEM_ALLOC"); |