bpf: Fix error checks against bpf_get_btf_vmlinux().

In bpf_struct_ops_map_alloc, it needs to check for NULL in the returned
pointer of bpf_get_btf_vmlinux() when CONFIG_DEBUG_INFO_BTF is not set.
ENOTSUPP is used to preserve the same behavior before the
struct_ops kmod support.

In the function check_struct_ops_btf_id(), instead of redoing the
bpf_get_btf_vmlinux() that has already been done in syscall.c, the fix
here is to check for prog->aux->attach_btf_id.
BPF_PROG_TYPE_STRUCT_OPS must require attach_btf_id and syscall.c
guarantees a valid attach_btf as long as attach_btf_id is set.
When attach_btf_id is not set, this patch returns -ENOTSUPP
because it is what the selftest in test_libbpf_probe_prog_types()
and libbpf_probes.c are expecting for feature probing purpose.

Changes from v1:

 - Remove an unnecessary NULL check in check_struct_ops_btf_id()

Reported-by: [email protected]
Closes: https://lore.kernel.org/bpf/[email protected]/
Reported-by: [email protected]
Closes: https://lore.kernel.org/bpf/[email protected]/
Fixes: fcc2c1fb0651 ("bpf: pass attached BTF to the bpf_struct_ops subsystem")
Signed-off-by: Kui-Feng Lee <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Martin KaFai Lau <[email protected]>

0 files changed, 0 insertions, 0 deletions