Commit 19bd300e authored by Mykyta Yatsenko's avatar Mykyta Yatsenko Committed by Andrii Nakryiko
Browse files

bpf: Add verifier support for bpf_timer argument in kfuncs 



Extend the verifier to recognize struct bpf_timer as a valid kfunc
argument type. Previously, bpf_timer was only supported in BPF helpers.

This prepares for adding timer-related kfuncs in subsequent patches.

Signed-off-by: default avatarMykyta Yatsenko <yatsenko@meta.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Acked-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20260201025403.66625-3-alexei.starovoitov@gmail.com
parent 1bfbc267

kernel/bpf/verifier.c

+37 −18
Original line number Diff line number Diff line
@@ -8675,13 +8675,25 @@ static int check_map_field_pointer(struct bpf_verifier_env *env, u32 regno, 
}









static int process_timer_func(struct bpf_verifier_env *env, int regno,









			      struct bpf_call_arg_meta *meta)









			      struct bpf_map_desc *map)









{









	if (IS_ENABLED(CONFIG_PREEMPT_RT)) {









		verbose(env, "bpf_timer cannot be used for PREEMPT_RT.\n");









		return -EOPNOTSUPP;









	}









	return check_map_field_pointer(env, regno, BPF_TIMER, &meta->map);









	return check_map_field_pointer(env, regno, BPF_TIMER, map);









}

















static int process_timer_helper(struct bpf_verifier_env *env, int regno,









				struct bpf_call_arg_meta *meta)









{









	return process_timer_func(env, regno, &meta->map);









}

















static int process_timer_kfunc(struct bpf_verifier_env *env, int regno,









			       struct bpf_kfunc_call_arg_meta *meta)









{









	return process_timer_func(env, regno, &meta->map);









}

















static int process_kptr_func(struct bpf_verifier_env *env, int regno,








@@ -9973,7 +9985,7 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg,







		}









		break;









	case ARG_PTR_TO_TIMER:









		err = process_timer_func(env, regno, meta);









		err = process_timer_helper(env, regno, meta);









		if (err)









			return err;









		break;








@@ -12238,7 +12250,8 @@ enum {







	KF_ARG_WORKQUEUE_ID,









	KF_ARG_RES_SPIN_LOCK_ID,









	KF_ARG_TASK_WORK_ID,









	KF_ARG_PROG_AUX_ID









	KF_ARG_PROG_AUX_ID,









	KF_ARG_TIMER_ID









};

















BTF_ID_LIST(kf_arg_btf_ids)








@@ -12251,6 +12264,7 @@ BTF_ID(struct, bpf_wq)







BTF_ID(struct, bpf_res_spin_lock)









BTF_ID(struct, bpf_task_work)









BTF_ID(struct, bpf_prog_aux)









BTF_ID(struct, bpf_timer)

















static bool __is_kfunc_ptr_arg_type(const struct btf *btf,









				    const struct btf_param *arg, int type)








@@ -12294,6 +12308,11 @@ static bool is_kfunc_arg_rbtree_node(const struct btf *btf, const struct btf_par







	return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_RB_NODE_ID);









}

















static bool is_kfunc_arg_timer(const struct btf *btf, const struct btf_param *arg)









{









	return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_TIMER_ID);









}

















static bool is_kfunc_arg_wq(const struct btf *btf, const struct btf_param *arg)









{









	return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_WORKQUEUE_ID);








@@ -12393,6 +12412,7 @@ enum kfunc_ptr_arg_type {







	KF_ARG_PTR_TO_NULL,









	KF_ARG_PTR_TO_CONST_STR,









	KF_ARG_PTR_TO_MAP,









	KF_ARG_PTR_TO_TIMER,









	KF_ARG_PTR_TO_WORKQUEUE,









	KF_ARG_PTR_TO_IRQ_FLAG,









	KF_ARG_PTR_TO_RES_SPIN_LOCK,








@@ -12646,6 +12666,9 @@ get_kfunc_ptr_arg_type(struct bpf_verifier_env *env,







	if (is_kfunc_arg_wq(meta->btf, &args[argno]))









		return KF_ARG_PTR_TO_WORKQUEUE;

















	if (is_kfunc_arg_timer(meta->btf, &args[argno]))









		return KF_ARG_PTR_TO_TIMER;

















	if (is_kfunc_arg_task_work(meta->btf, &args[argno]))









		return KF_ARG_PTR_TO_TASK_WORK;
















@@ -13439,6 +13462,7 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_







		case KF_ARG_PTR_TO_REFCOUNTED_KPTR:









		case KF_ARG_PTR_TO_CONST_STR:









		case KF_ARG_PTR_TO_WORKQUEUE:









		case KF_ARG_PTR_TO_TIMER:









		case KF_ARG_PTR_TO_TASK_WORK:









		case KF_ARG_PTR_TO_IRQ_FLAG:









		case KF_ARG_PTR_TO_RES_SPIN_LOCK:








@@ -13738,6 +13762,15 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_







			if (ret < 0)









				return ret;









			break;









		case KF_ARG_PTR_TO_TIMER:









			if (reg->type != PTR_TO_MAP_VALUE) {









				verbose(env, "arg#%d doesn't point to a map value\n", i);









				return -EINVAL;









			}









			ret = process_timer_kfunc(env, regno, meta);









			if (ret < 0)









				return ret;









			break;









		case KF_ARG_PTR_TO_TASK_WORK:









			if (reg->type != PTR_TO_MAP_VALUE) {









				verbose(env, "arg#%d doesn't point to a map value\n", i);








@@ -21429,20 +21462,6 @@ static int check_map_prog_compatibility(struct bpf_verifier_env *env,







		}









	}

















	if (btf_record_has_field(map->record, BPF_TIMER)) {









		if (is_tracing_prog_type(prog_type)) {









			verbose(env, "tracing progs cannot use bpf_timer yet\n");









			return -EINVAL;









		}









	}

















	if (btf_record_has_field(map->record, BPF_WORKQUEUE)) {









		if (is_tracing_prog_type(prog_type)) {









			verbose(env, "tracing progs cannot use bpf_wq yet\n");









			return -EINVAL;









		}









	}

















	if ((bpf_prog_is_offloaded(prog->aux) || bpf_map_is_offloaded(map)) &&









	    !bpf_offload_prog_map_match(prog, map)) {









		verbose(env, "offload device mismatch between prog and map\n");