fbc5bc4c8e
Add a selftest for the fix provided in the previous commit. Without the fix, the selftest passes the verifier while it should fail. The special logic for detecting graph root or node for reg->off and bypassing reg->off == 0 guarantee for release helpers/kfuncs has been dropped. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/r/20230822175140.1317749-3-memxor@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
85 lines
1.8 KiB
C
85 lines
1.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
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#include <vmlinux.h>
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#include <bpf/bpf_helpers.h>
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#include <bpf/bpf_tracing.h>
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#include <bpf/bpf_core_read.h>
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#include "../bpf_experimental.h"
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#include "bpf_misc.h"
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struct node_data {
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long key;
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long data;
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struct bpf_rb_node node;
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};
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struct map_value {
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struct node_data __kptr *node;
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};
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struct node_data2 {
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long key[4];
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};
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/* This is necessary so that LLVM generates BTF for node_data struct
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* If it's not included, a fwd reference for node_data will be generated but
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* no struct. Example BTF of "node" field in map_value when not included:
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*
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* [10] PTR '(anon)' type_id=35
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* [34] FWD 'node_data' fwd_kind=struct
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* [35] TYPE_TAG 'kptr_ref' type_id=34
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*/
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struct node_data *just_here_because_btf_bug;
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struct {
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__uint(type, BPF_MAP_TYPE_ARRAY);
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__type(key, int);
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__type(value, struct map_value);
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__uint(max_entries, 2);
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} some_nodes SEC(".maps");
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SEC("tc")
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__failure __msg("invalid kptr access, R2 type=ptr_node_data2 expected=ptr_node_data")
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long stash_rb_nodes(void *ctx)
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{
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struct map_value *mapval;
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struct node_data2 *res;
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int idx = 0;
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mapval = bpf_map_lookup_elem(&some_nodes, &idx);
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if (!mapval)
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return 1;
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res = bpf_obj_new(typeof(*res));
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if (!res)
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return 1;
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res->key[0] = 40;
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res = bpf_kptr_xchg(&mapval->node, res);
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if (res)
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bpf_obj_drop(res);
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return 0;
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}
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SEC("tc")
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__failure __msg("R1 must have zero offset when passed to release func")
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long drop_rb_node_off(void *ctx)
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{
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struct map_value *mapval;
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struct node_data *res;
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int idx = 0;
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mapval = bpf_map_lookup_elem(&some_nodes, &idx);
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if (!mapval)
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return 1;
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res = bpf_obj_new(typeof(*res));
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if (!res)
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return 1;
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/* Try releasing with graph node offset */
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bpf_obj_drop(&res->node);
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return 0;
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}
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char _license[] SEC("license") = "GPL";
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