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Message-ID: <20260109184852.1089786-7-ihor.solodrai@linux.dev>
Date: Fri, 9 Jan 2026 10:48:48 -0800
From: Ihor Solodrai <ihor.solodrai@...ux.dev>
To: Alexei Starovoitov <ast@...nel.org>,
Andrii Nakryiko <andrii@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>,
Martin KaFai Lau <martin.lau@...ux.dev>,
Eduard Zingerman <eddyz87@...il.com>
Cc: Mykyta Yatsenko <yatsenko@...a.com>,
Tejun Heo <tj@...nel.org>,
Alan Maguire <alan.maguire@...cle.com>,
Benjamin Tissoires <bentiss@...nel.org>,
Jiri Kosina <jikos@...nel.org>,
bpf@...r.kernel.org,
linux-kernel@...r.kernel.org,
linux-input@...r.kernel.org,
sched-ext@...ts.linux.dev
Subject: [PATCH bpf-next v1 06/10] bpf: Add bpf_wq_set_callback kfunc with KF_IMPLICIT_ARGS
Implement bpf_wq_set_callback() with an implicit bpf_prog_aux
argument, and change bpf_wq_set_callback_impl() to call the new kfunc.
Update special kfunc checks in the verifier to accept both versions of
the function.
In the selftests, a bpf_wq_set_callback_impl() call is intentionally
introduced to confirm that both signatures are handled correctly.
Signed-off-by: Ihor Solodrai <ihor.solodrai@...ux.dev>
---
kernel/bpf/helpers.c | 18 +++++++++++++-----
kernel/bpf/verifier.c | 15 +++++++++------
tools/testing/selftests/bpf/bpf_experimental.h | 5 -----
tools/testing/selftests/bpf/progs/wq.c | 2 +-
.../testing/selftests/bpf/progs/wq_failures.c | 4 ++--
5 files changed, 25 insertions(+), 19 deletions(-)
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 9eaa4185e0a7..23aa785c0f99 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -3120,12 +3120,11 @@ __bpf_kfunc int bpf_wq_start(struct bpf_wq *wq, unsigned int flags)
return 0;
}
-__bpf_kfunc int bpf_wq_set_callback_impl(struct bpf_wq *wq,
- int (callback_fn)(void *map, int *key, void *value),
- unsigned int flags,
- void *aux__prog)
+__bpf_kfunc int bpf_wq_set_callback(struct bpf_wq *wq,
+ int (callback_fn)(void *map, int *key, void *value),
+ unsigned int flags,
+ struct bpf_prog_aux *aux)
{
- struct bpf_prog_aux *aux = (struct bpf_prog_aux *)aux__prog;
struct bpf_async_kern *async = (struct bpf_async_kern *)wq;
if (flags)
@@ -3134,6 +3133,14 @@ __bpf_kfunc int bpf_wq_set_callback_impl(struct bpf_wq *wq,
return __bpf_async_set_callback(async, callback_fn, aux, flags, BPF_ASYNC_TYPE_WQ);
}
+__bpf_kfunc int bpf_wq_set_callback_impl(struct bpf_wq *wq,
+ int (callback_fn)(void *map, int *key, void *value),
+ unsigned int flags,
+ void *aux__prog)
+{
+ return bpf_wq_set_callback(wq, callback_fn, flags, aux__prog);
+}
+
__bpf_kfunc void bpf_preempt_disable(void)
{
preempt_disable();
@@ -4488,6 +4495,7 @@ BTF_ID_FLAGS(func, bpf_dynptr_memset)
BTF_ID_FLAGS(func, bpf_modify_return_test_tp)
#endif
BTF_ID_FLAGS(func, bpf_wq_init)
+BTF_ID_FLAGS(func, bpf_wq_set_callback, KF_IMPLICIT_ARGS)
BTF_ID_FLAGS(func, bpf_wq_set_callback_impl)
BTF_ID_FLAGS(func, bpf_wq_start)
BTF_ID_FLAGS(func, bpf_preempt_disable)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 5541ab674e30..e5aeee554377 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -520,7 +520,7 @@ static bool is_async_callback_calling_kfunc(u32 btf_id);
static bool is_callback_calling_kfunc(u32 btf_id);
static bool is_bpf_throw_kfunc(struct bpf_insn *insn);
-static bool is_bpf_wq_set_callback_impl_kfunc(u32 btf_id);
+static bool is_bpf_wq_set_callback_kfunc(u32 btf_id);
static bool is_task_work_add_kfunc(u32 func_id);
static bool is_sync_callback_calling_function(enum bpf_func_id func_id)
@@ -562,7 +562,7 @@ static bool is_async_cb_sleepable(struct bpf_verifier_env *env, struct bpf_insn
/* bpf_wq and bpf_task_work callbacks are always sleepable. */
if (bpf_pseudo_kfunc_call(insn) && insn->off == 0 &&
- (is_bpf_wq_set_callback_impl_kfunc(insn->imm) || is_task_work_add_kfunc(insn->imm)))
+ (is_bpf_wq_set_callback_kfunc(insn->imm) || is_task_work_add_kfunc(insn->imm)))
return true;
verifier_bug(env, "unhandled async callback in is_async_cb_sleepable");
@@ -12470,6 +12470,7 @@ enum special_kfunc_type {
KF_bpf_arena_alloc_pages,
KF_bpf_arena_free_pages,
KF_bpf_arena_reserve_pages,
+ KF_bpf_wq_set_callback,
};
BTF_ID_LIST(special_kfunc_list)
@@ -12547,6 +12548,7 @@ BTF_ID(func, bpf_task_work_schedule_resume_impl)
BTF_ID(func, bpf_arena_alloc_pages)
BTF_ID(func, bpf_arena_free_pages)
BTF_ID(func, bpf_arena_reserve_pages)
+BTF_ID(func, bpf_wq_set_callback)
static bool is_task_work_add_kfunc(u32 func_id)
{
@@ -13002,7 +13004,7 @@ static bool is_sync_callback_calling_kfunc(u32 btf_id)
static bool is_async_callback_calling_kfunc(u32 btf_id)
{
- return btf_id == special_kfunc_list[KF_bpf_wq_set_callback_impl] ||
+ return is_bpf_wq_set_callback_kfunc(btf_id) ||
is_task_work_add_kfunc(btf_id);
}
@@ -13012,9 +13014,10 @@ static bool is_bpf_throw_kfunc(struct bpf_insn *insn)
insn->imm == special_kfunc_list[KF_bpf_throw];
}
-static bool is_bpf_wq_set_callback_impl_kfunc(u32 btf_id)
+static bool is_bpf_wq_set_callback_kfunc(u32 btf_id)
{
- return btf_id == special_kfunc_list[KF_bpf_wq_set_callback_impl];
+ return btf_id == special_kfunc_list[KF_bpf_wq_set_callback_impl] ||
+ btf_id == special_kfunc_list[KF_bpf_wq_set_callback];
}
static bool is_callback_calling_kfunc(u32 btf_id)
@@ -14093,7 +14096,7 @@ static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
meta.r0_rdonly = false;
}
- if (is_bpf_wq_set_callback_impl_kfunc(meta.func_id)) {
+ if (is_bpf_wq_set_callback_kfunc(meta.func_id)) {
err = push_callback_call(env, insn, insn_idx, meta.subprogno,
set_timer_callback_state);
if (err) {
diff --git a/tools/testing/selftests/bpf/bpf_experimental.h b/tools/testing/selftests/bpf/bpf_experimental.h
index 2cd9165c7348..68a49b1f77ae 100644
--- a/tools/testing/selftests/bpf/bpf_experimental.h
+++ b/tools/testing/selftests/bpf/bpf_experimental.h
@@ -580,11 +580,6 @@ extern void bpf_iter_css_destroy(struct bpf_iter_css *it) __weak __ksym;
extern int bpf_wq_init(struct bpf_wq *wq, void *p__map, unsigned int flags) __weak __ksym;
extern int bpf_wq_start(struct bpf_wq *wq, unsigned int flags) __weak __ksym;
-extern int bpf_wq_set_callback_impl(struct bpf_wq *wq,
- int (callback_fn)(void *map, int *key, void *value),
- unsigned int flags__k, void *aux__ign) __ksym;
-#define bpf_wq_set_callback(timer, cb, flags) \
- bpf_wq_set_callback_impl(timer, cb, flags, NULL)
struct bpf_iter_kmem_cache;
extern int bpf_iter_kmem_cache_new(struct bpf_iter_kmem_cache *it) __weak __ksym;
diff --git a/tools/testing/selftests/bpf/progs/wq.c b/tools/testing/selftests/bpf/progs/wq.c
index 25be2cd9d42c..f265242b954d 100644
--- a/tools/testing/selftests/bpf/progs/wq.c
+++ b/tools/testing/selftests/bpf/progs/wq.c
@@ -107,7 +107,7 @@ static int test_hmap_elem_callback(void *map, int *key,
if (bpf_wq_init(wq, map, 0) != 0)
return -3;
- if (bpf_wq_set_callback(wq, callback_fn, 0))
+ if (bpf_wq_set_callback_impl(wq, callback_fn, 0, NULL))
return -4;
if (bpf_wq_start(wq, 0))
diff --git a/tools/testing/selftests/bpf/progs/wq_failures.c b/tools/testing/selftests/bpf/progs/wq_failures.c
index d06f6d40594a..3767f5595bbc 100644
--- a/tools/testing/selftests/bpf/progs/wq_failures.c
+++ b/tools/testing/selftests/bpf/progs/wq_failures.c
@@ -97,7 +97,7 @@ __failure
/* check that the first argument of bpf_wq_set_callback()
* is a correct bpf_wq pointer.
*/
-__msg(": (85) call bpf_wq_set_callback_impl#") /* anchor message */
+__msg(": (85) call bpf_wq_set_callback#") /* anchor message */
__msg("arg#0 doesn't point to a map value")
long test_wrong_wq_pointer(void *ctx)
{
@@ -123,7 +123,7 @@ __failure
/* check that the first argument of bpf_wq_set_callback()
* is a correct bpf_wq pointer.
*/
-__msg(": (85) call bpf_wq_set_callback_impl#") /* anchor message */
+__msg(": (85) call bpf_wq_set_callback#") /* anchor message */
__msg("off 1 doesn't point to 'struct bpf_wq' that is at 0")
long test_wrong_wq_pointer_offset(void *ctx)
{
--
2.52.0
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