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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: Mykyta Yatsenko <yatsenko@meta.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20260201025403.66625-3-alexei.starovoitov@gmail.com
master
Mykyta Yatsenko 2026-01-31 18:53:56 -08:00 committed by Andrii Nakryiko
parent 1bfbc267ec
commit 19bd300e22
1 changed files with 37 additions and 18 deletions
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55
kernel/bpf/verifier.c
View File

@ -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 @@ skip_type_check:
}
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");