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| author | Yonghong Song <yonghong.song@linux.dev> | 2024-11-12 17:39:33 +0100 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2024-11-13 01:26:25 +0100 |
| commit | 5bd36da1e37e7a78e8b38efd287de6e1394b7d6e (patch) | |
| tree | 44a082b24b2c227d10d755f17d5e44d7504a5491 /include | |
| parent | selftests/bpf: Add tracing prog private stack tests (diff) | |
| download | linux-5bd36da1e37e7a78e8b38efd287de6e1394b7d6e.tar.xz linux-5bd36da1e37e7a78e8b38efd287de6e1394b7d6e.zip | |
bpf: Support private stack for struct_ops progs
For struct_ops progs, whether a particular prog uses private stack
depends on prog->aux->priv_stack_requested setting before actual
insn-level verification for that prog. One particular implementation
is to piggyback on struct_ops->check_member(). The next patch has
an example for this. The struct_ops->check_member() sets
prog->aux->priv_stack_requested to be true which enables private stack
usage.
The struct_ops prog follows the same rule as kprobe/tracing progs after
function bpf_enable_priv_stack(). For example, even a struct_ops prog
requests private stack, it could still use normal kernel stack if
the stack size is small (< 64 bytes).
Similar to tracing progs, nested same cpu same prog run will be skipped.
A field (recursion_detected()) is added to bpf_prog_aux structure.
If bpf_prog->aux->recursion_detected is implemented by the struct_ops
subsystem and nested same cpu/prog happens, the function will be
triggered to report an error, collect related info, etc.
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20241112163933.2224962-1-yonghong.song@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/bpf.h | 2 | ||||
| -rw-r--r-- | include/linux/bpf_verifier.h | 1 |
2 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index d32cc373dfd1..10945c8858ce 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1525,9 +1525,11 @@ struct bpf_prog_aux { bool exception_boundary; bool is_extended; /* true if extended by freplace program */ bool jits_use_priv_stack; + bool priv_stack_requested; u64 prog_array_member_cnt; /* counts how many times as member of prog_array */ struct mutex ext_mutex; /* mutex for is_extended and prog_array_member_cnt */ struct bpf_arena *arena; + void (*recursion_detected)(struct bpf_prog *prog); /* callback if recursion is detected */ /* BTF_KIND_FUNC_PROTO for valid attach_btf_id */ const struct btf_type *attach_func_proto; /* function name for valid attach_btf_id */ diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h index d62bb2ca1828..6b7c91629176 100644 --- a/include/linux/bpf_verifier.h +++ b/include/linux/bpf_verifier.h @@ -879,6 +879,7 @@ static inline bool bpf_prog_check_recur(const struct bpf_prog *prog) case BPF_PROG_TYPE_TRACING: return prog->expected_attach_type != BPF_TRACE_ITER; case BPF_PROG_TYPE_STRUCT_OPS: + return prog->aux->jits_use_priv_stack; case BPF_PROG_TYPE_LSM: return false; default: |