[PATCH bpf-next v1 5/6] bpf: mark bpf_stream_vprink kfunc with KF_IMPLICIT_PROG_AUX_ARG

Ihor Solodrai
2025-09-24T21:17:52Z

Update bpf_stream_vprink macro in libbpf and fix call sites in
the relevant selftests.

Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
---
kernel/bpf/helpers.c | 2 +-
kernel/bpf/stream.c | 3 +--
tools/lib/bpf/bpf_helpers.h | 4 ++--
tools/testing/selftests/bpf/progs/stream_fail.c | 6 +++---
4 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 6b46acfec790..875195a0ea72 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -4378,7 +4378,7 @@ BTF_ID_FLAGS(func, bpf_strnstr);
#if defined(CONFIG_BPF_LSM) && defined(CONFIG_CGROUPS)
BTF_ID_FLAGS(func, bpf_cgroup_read_xattr, KF_RCU)
#endif
-BTF_ID_FLAGS(func, bpf_stream_vprintk, KF_TRUSTED_ARGS)
+BTF_ID_FLAGS(func, bpf_stream_vprintk, KF_TRUSTED_ARGS | KF_IMPLICIT_PROG_AUX_ARG)
BTF_ID_FLAGS(func, bpf_task_work_schedule_signal, KF_TRUSTED_ARGS)
BTF_ID_FLAGS(func, bpf_task_work_schedule_resume, KF_TRUSTED_ARGS)
BTF_ID_FLAGS(func, bpf_wq_set_callback, KF_IMPLICIT_PROG_AUX_ARG)
diff --git a/kernel/bpf/stream.c b/kernel/bpf/stream.c
index ab592db4a4bf..0c75d0a8cea2 100644
--- a/kernel/bpf/stream.c
+++ b/kernel/bpf/stream.c
@@ -355,13 +355,12 @@ __bpf_kfunc_start_defs();
* Avoid using enum bpf_stream_id so that kfunc users don't have to pull in the
* enum in headers.
*/
-__bpf_kfunc int bpf_stream_vprintk(int stream_id, const char *fmt__str, const void *args, u32 len__sz, void *aux__prog)
+__bpf_kfunc int bpf_stream_vprintk(int stream_id, const char *fmt__str, const void *args, u32 len__sz, struct bpf_prog_aux *aux)
{
struct bpf_bprintf_data data = {
.get_bin_args = true,
.get_buf = true,
};
- struct bpf_prog_aux *aux = aux__prog;
u32 fmt_size = strlen(fmt__str) + 1;
struct bpf_stream *stream;
u32 data_len = len__sz;
diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h
index 80c028540656..9a6d719315a3 100644
--- a/tools/lib/bpf/bpf_helpers.h
+++ b/tools/lib/bpf/bpf_helpers.h
@@ -316,7 +316,7 @@ enum libbpf_tristate {
})

extern int bpf_stream_vprintk(int stream_id, const char *fmt__str, const void *args,
- __u32 len__sz, void *aux__prog) __weak __ksym;
+ __u32 len__sz) __weak __ksym;

#define bpf_stream_printk(stream_id, fmt, args...) \
({ \
@@ -328,7 +328,7 @@ extern int bpf_stream_vprintk(int stream_id, const char *fmt__str, const void *a
___bpf_fill(___param, args); \
_Pragma("GCC diagnostic pop") \
\
- bpf_stream_vprintk(stream_id, ___fmt, ___param, sizeof(___param), NULL);\
+ bpf_stream_vprintk(stream_id, ___fmt, ___param, sizeof(___param));\
})

/* Use __bpf_printk when bpf_printk call has 3 or fewer fmt args
diff --git a/tools/testing/selftests/bpf/progs/stream_fail.c b/tools/testing/selftests/bpf/progs/stream_fail.c
index b4a0d0cc8ec8..8e8249f3521c 100644
--- a/tools/testing/selftests/bpf/progs/stream_fail.c
+++ b/tools/testing/selftests/bpf/progs/stream_fail.c
@@ -10,7 +10,7 @@ SEC("syscall")
__failure __msg("Possibly NULL pointer passed")
int stream_vprintk_null_arg(void *ctx)
{
- bpf_stream_vprintk(BPF_STDOUT, "", NULL, 0, NULL);
+ bpf_stream_vprintk(BPF_STDOUT, "", NULL, 0);
return 0;
}

@@ -18,7 +18,7 @@ SEC("syscall")
__failure __msg("R3 type=scalar expected=")
int stream_vprintk_scalar_arg(void *ctx)
{
- bpf_stream_vprintk(BPF_STDOUT, "", (void *)46, 0, NULL);
+ bpf_stream_vprintk(BPF_STDOUT, "", (void *)46, 0);
return 0;
}

@@ -26,7 +26,7 @@ SEC("syscall")
__failure __msg("arg#1 doesn't point to a const string")
int stream_vprintk_string_arg(void *ctx)
{
- bpf_stream_vprintk(BPF_STDOUT, ctx, NULL, 0, NULL);
+ bpf_stream_vprintk(BPF_STDOUT, ctx, NULL, 0);
return 0;
}

--
2.51.0