> On Feb 28, 2023, at 3:08 PM, Martin KaFai Lau <martin.lau@xxxxxxxxx> wrote: > > On 2/23/23 1:53 PM, Aditi Ghag wrote: >> The test cases for TCP and UDP iterators mirror the intended usages of the >> helper. >> The destroy helpers set `ECONNABORTED` error code that we can validate in the >> test code with client sockets. But UDP sockets have an overriding error code >> from the disconnect called during abort, so the error code the validation is >> only done for TCP sockets. >> The `struct sock` is redefined as vmlinux.h forward declares the struct, and the >> loader fails to load the program as it finds the BTF FWD type for the struct >> incompatible with the BTF STRUCT type. >> Here are the snippets of the verifier error, and corresponding BTF output: >> ``` >> verifier error: extern (func ksym) ...: func_proto ... incompatible with kernel >> BTF for selftest prog binary: >> [104] FWD 'sock' fwd_kind=struct >> [70] PTR '(anon)' type_id=104 >> [84] FUNC_PROTO '(anon)' ret_type_id=2 vlen=1 >> '(anon)' type_id=70 >> [85] FUNC 'bpf_sock_destroy' type_id=84 linkage=extern >> -- >> [96] DATASEC '.ksyms' size=0 vlen=1 >> type_id=85 offset=0 size=0 (FUNC 'bpf_sock_destroy') >> BTF for selftest vmlinux: >> [74923] FUNC 'bpf_sock_destroy' type_id=48965 linkage=static >> [48965] FUNC_PROTO '(anon)' ret_type_id=9 vlen=1 >> 'sk' type_id=1340 >> [1340] PTR '(anon)' type_id=2363 >> [2363] STRUCT 'sock' size=1280 vlen=93 >> ``` > >> +int bpf_sock_destroy(struct sock_common *sk) __ksym; > > This does not match the bpf prog's BTF dump above which has pointer [70] pointing to FWD 'sock' [104] as the argument. It should be at least FWD 'sock_common' if not STRUCT 'sock_common'. I tried to change the func signature to 'struct sock *sk' but cannot reproduce the issue in my environment also. > > Could you confirm the BTF paste and 'incompatible with kernel" error in the commit message do match the bpf_sock_destroy declaration? If not, can you re-paste the BTF output and libbpf error message that matches the bpf_sock_destroy signature. I don't think you'll be able to reproduce the issue with `sock_common`, as `struct sock_common` isn't forward declared in vmlinux.h. But I find it odd that you weren't able to reproduce it with `struct sock`. Just to confirm, did you remove the minimal `struct sock` definition from the program? Per the commit description, I added that because libbpf was throwing this error - `libbpf: extern (func ksym) 'bpf_sock_destroy': func_proto [83] incompatible with kernel [75285]` Sending the BTF snippet again (full BTF - https://pastebin.com/etkFyuJk) ``` 85] FUNC 'bpf_sock_destroy' type_id=84 linkage=extern type_id=85 offset=0 size=0 (FUNC 'bpf_sock_destroy') [84] FUNC_PROTO '(anon)' ret_type_id=2 vlen=1 '(anon)' type_id=70 [70] PTR '(anon)' type_id=104 [104] FWD 'sock' fwd_kind=struct ``` Compare this to the BTF snippet once I undef and define the struct in the test prog: ``` [87] FUNC 'bpf_sock_destroy' type_id=84 linkage=extern type_id=87 offset=0 size=0 (FUNC 'bpf_sock_destroy') [84] FUNC_PROTO '(anon)' ret_type_id=2 vlen=1 '(anon)' type_id=85 [85] PTR '(anon)' type_id=86 [86] STRUCT 'sock' size=136 vlen=1 '__sk_common' type_id=34 bits_offset=0 ``` (Anyway looks like I needed to define the struct in the test prog only when bpf_sock_destory had `struct sock` as the argument.)
