diff mbox series

[v4,bpf-next,1/6] bpf: Allow kfuncs return 'void *'

Message ID 20240307031228.42896-2-alexei.starovoitov@gmail.com (mailing list archive)
State Accepted
Commit 88d1d4a7eebea2836859246d91fe9d141789dfc3
Delegated to: BPF
Headers show
Series bpf: arena prerequisites | expand

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netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 952 this patch: 952
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netdev/cc_maintainers warning 8 maintainers not CCed: song@kernel.org john.fastabend@gmail.com haoluo@google.com yonghong.song@linux.dev sdf@google.com martin.lau@linux.dev kpsingh@kernel.org jolsa@kernel.org
netdev/build_clang success Errors and warnings before: 957 this patch: 957
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netdev/checkpatch warning WARNING: line length of 88 exceeds 80 columns
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Commit Message

Alexei Starovoitov March 7, 2024, 3:12 a.m. UTC 
From: Alexei Starovoitov <ast@kernel.org>

Recognize return of 'void *' from kfunc as returning unknown scalar.

Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
 kernel/bpf/verifier.c | 3 +++
 1 file changed, 3 insertions(+)
diff mbox series

Patch

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index ee86e4d7d5fc..9c2a36b1373b 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -12364,6 +12364,9 @@  static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
 					meta.func_name);
 				return -EFAULT;
 			}
+		} else if (btf_type_is_void(ptr_type)) {
+			/* kfunc returning 'void *' is equivalent to returning scalar */
+			mark_reg_unknown(env, regs, BPF_REG_0);
 		} else if (!__btf_type_is_struct(ptr_type)) {
 			if (!meta.r0_size) {
 				__u32 sz;