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bpf: Rename RET_PTR_TO_ALLOC_MEM

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Currently, the verifier has two return types, RET_PTR_TO_ALLOC_MEM, and
RET_PTR_TO_ALLOC_MEM_OR_NULL, however the former is confusingly named to
imply that it carries MEM_ALLOC, while only the latter does. This causes
confusion during code review leading to conclusions like that the return
value of RET_PTR_TO_DYNPTR_MEM_OR_NULL (which is RET_PTR_TO_ALLOC_MEM |
PTR_MAYBE_NULL) may be consumable by bpf_ringbuf_{submit,commit}.

Rename it to make it clear MEM_ALLOC needs to be tacked on top of
RET_PTR_TO_MEM.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221114191547.1694267-6-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Kumar Kartikeya Dwivedi 2022-11-15 00:45:26 +05:30 committed by Alexei Starovoitov
parent f0c5941ff5
commit 2de2669b4e
2 changed files with 4 additions and 4 deletions
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6
include/linux/bpf.h
View File

@ -607,7 +607,7 @@ enum bpf_return_type {
RET_PTR_TO_SOCKET, /* returns a pointer to a socket */
RET_PTR_TO_TCP_SOCK, /* returns a pointer to a tcp_sock */
RET_PTR_TO_SOCK_COMMON, /* returns a pointer to a sock_common */
RET_PTR_TO_ALLOC_MEM, /* returns a pointer to dynamically allocated memory */
RET_PTR_TO_MEM, /* returns a pointer to memory */
RET_PTR_TO_MEM_OR_BTF_ID, /* returns a pointer to a valid memory or a btf_id */
RET_PTR_TO_BTF_ID, /* returns a pointer to a btf_id */
__BPF_RET_TYPE_MAX,
@ -617,8 +617,8 @@ enum bpf_return_type {
RET_PTR_TO_SOCKET_OR_NULL = PTR_MAYBE_NULL | RET_PTR_TO_SOCKET,
RET_PTR_TO_TCP_SOCK_OR_NULL = PTR_MAYBE_NULL | RET_PTR_TO_TCP_SOCK,
RET_PTR_TO_SOCK_COMMON_OR_NULL = PTR_MAYBE_NULL | RET_PTR_TO_SOCK_COMMON,
RET_PTR_TO_ALLOC_MEM_OR_NULL = PTR_MAYBE_NULL | MEM_ALLOC | RET_PTR_TO_ALLOC_MEM,
RET_PTR_TO_DYNPTR_MEM_OR_NULL = PTR_MAYBE_NULL | RET_PTR_TO_ALLOC_MEM,
RET_PTR_TO_ALLOC_MEM_OR_NULL = PTR_MAYBE_NULL | MEM_ALLOC | RET_PTR_TO_MEM,
RET_PTR_TO_DYNPTR_MEM_OR_NULL = PTR_MAYBE_NULL | RET_PTR_TO_MEM,
RET_PTR_TO_BTF_ID_OR_NULL = PTR_MAYBE_NULL | RET_PTR_TO_BTF_ID,
/* This must be the last entry. Its purpose is to ensure the enum is

2
kernel/bpf/verifier.c
View File

@ -7630,7 +7630,7 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn
mark_reg_known_zero(env, regs, BPF_REG_0);
regs[BPF_REG_0].type = PTR_TO_TCP_SOCK | ret_flag;
break;
case RET_PTR_TO_ALLOC_MEM:
case RET_PTR_TO_MEM:
mark_reg_known_zero(env, regs, BPF_REG_0);
regs[BPF_REG_0].type = PTR_TO_MEM | ret_flag;
regs[BPF_REG_0].mem_size = meta.mem_size;