Commit 01685c5b authored by Yonghong Song's avatar Yonghong Song Committed by Alexei Starovoitov
Browse files

bpf: Introduce might_sleep field in bpf_func_proto 



Introduce bpf_func_proto->might_sleep to indicate a particular helper
might sleep. This will make later check whether a helper might be
sleepable or not easier.

Acked-by: default avatarMartin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: default avatarYonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/r/20221124053211.2373553-1-yhs@fb.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 5a0f663f

include/linux/bpf.h

+1 −0
Original line number Diff line number Diff line
@@ -682,6 +682,7 @@ struct bpf_func_proto { 
	u64 (*func)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);

	bool gpl_only;

	bool pkt_access;

	bool might_sleep;

	enum bpf_return_type ret_type;

	union {

		struct {

kernel/bpf/bpf_lsm.c

+4 −2
Original line number Diff line number Diff line
@@ -151,6 +151,7 @@ BTF_ID_LIST_SINGLE(bpf_ima_inode_hash_btf_ids, struct, inode) 
static const struct bpf_func_proto bpf_ima_inode_hash_proto = {

	.func		= bpf_ima_inode_hash,

	.gpl_only	= false,

	.might_sleep	= true,

	.ret_type	= RET_INTEGER,

	.arg1_type	= ARG_PTR_TO_BTF_ID,

	.arg1_btf_id	= &bpf_ima_inode_hash_btf_ids[0],
@@ -169,6 +170,7 @@ BTF_ID_LIST_SINGLE(bpf_ima_file_hash_btf_ids, struct, file) 
static const struct bpf_func_proto bpf_ima_file_hash_proto = {

	.func		= bpf_ima_file_hash,

	.gpl_only	= false,

	.might_sleep	= true,

	.ret_type	= RET_INTEGER,

	.arg1_type	= ARG_PTR_TO_BTF_ID,

	.arg1_btf_id	= &bpf_ima_file_hash_btf_ids[0],
@@ -221,9 +223,9 @@ bpf_lsm_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 
	case BPF_FUNC_bprm_opts_set:

		return &bpf_bprm_opts_set_proto;

	case BPF_FUNC_ima_inode_hash:

		return prog->aux->sleepable ? &bpf_ima_inode_hash_proto : NULL;

		return &bpf_ima_inode_hash_proto;

	case BPF_FUNC_ima_file_hash:

		return prog->aux->sleepable ? &bpf_ima_file_hash_proto : NULL;

		return &bpf_ima_file_hash_proto;

	case BPF_FUNC_get_attach_cookie:

		return bpf_prog_has_trampoline(prog) ? &bpf_get_attach_cookie_proto : NULL;

#ifdef CONFIG_NET

kernel/bpf/helpers.c

+2 −0
Original line number Diff line number Diff line
@@ -661,6 +661,7 @@ BPF_CALL_3(bpf_copy_from_user, void *, dst, u32, size, 
const struct bpf_func_proto bpf_copy_from_user_proto = {

	.func		= bpf_copy_from_user,

	.gpl_only	= false,

	.might_sleep	= true,

	.ret_type	= RET_INTEGER,

	.arg1_type	= ARG_PTR_TO_UNINIT_MEM,

	.arg2_type	= ARG_CONST_SIZE_OR_ZERO,
@@ -691,6 +692,7 @@ BPF_CALL_5(bpf_copy_from_user_task, void *, dst, u32, size, 
const struct bpf_func_proto bpf_copy_from_user_task_proto = {

	.func		= bpf_copy_from_user_task,

	.gpl_only	= true,

	.might_sleep	= true,

	.ret_type	= RET_INTEGER,

	.arg1_type	= ARG_PTR_TO_UNINIT_MEM,

	.arg2_type	= ARG_CONST_SIZE_OR_ZERO,

kernel/bpf/verifier.c

+5 −0
Original line number Diff line number Diff line
@@ -7516,6 +7516,11 @@ static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn 
		return -EINVAL;

	}



	if (!env->prog->aux->sleepable && fn->might_sleep) {

		verbose(env, "helper call might sleep in a non-sleepable prog\n");

		return -EINVAL;

	}



	/* With LD_ABS/IND some JITs save/restore skb from r1. */

	changes_data = bpf_helper_changes_pkt_data(fn->func);

	if (changes_data && fn->arg1_type != ARG_PTR_TO_CTX) {

kernel/trace/bpf_trace.c

+2 −2
Original line number Diff line number Diff line
@@ -1485,9 +1485,9 @@ bpf_tracing_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) 
	case BPF_FUNC_get_task_stack:

		return &bpf_get_task_stack_proto;

	case BPF_FUNC_copy_from_user:

		return prog->aux->sleepable ? &bpf_copy_from_user_proto : NULL;

		return &bpf_copy_from_user_proto;

	case BPF_FUNC_copy_from_user_task:

		return prog->aux->sleepable ? &bpf_copy_from_user_task_proto : NULL;

		return &bpf_copy_from_user_task_proto;

	case BPF_FUNC_snprintf_btf:

		return &bpf_snprintf_btf_proto;

	case BPF_FUNC_per_cpu_ptr: