From: Jiri Olsa <jolsa@kernel.org>
To: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>
Cc: bpf@vger.kernel.org, linux-mm@kvack.org,
Andrii Nakryiko <andrii@kernel.org>,
Eduard Zingerman <eddyz87@gmail.com>,
Kumar Kartikeya Dwivedi <memxor@gmail.com>,
Lorenzo Stoakes <ljs@kernel.org>,
John Fastabend <john.fastabend@gmail.com>,
Federico Di Pierro <nierro92@gmail.com>
Subject: [PATCH bpf-next 4/8] selftests/bpf: Test __srcptr kfunc arguments
Date: Thu, 29 Oct 2026 22:25:47 +0100 [thread overview]
Message-ID: <20261029212551.56964-5-jolsa@kernel.org> (raw)
In-Reply-To: <20261029212551.56964-1-jolsa@kernel.org>
Verify that __srcptr kfunc arguments accept read-only global data,
writable stack data, and a pointer to a read-only struct of scalars.
Also verify that read-only data is rejected when passed to a kfunc
argument that requires writable memory.
Assisted-by: Codex:GPT-6
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
.../testing/selftests/bpf/prog_tests/kfunc_call.c | 2 ++
.../testing/selftests/bpf/progs/kfunc_call_fail.c | 10 ++++++++++
.../testing/selftests/bpf/progs/kfunc_call_test.c | 14 ++++++++++++++
.../testing/selftests/bpf/test_kmods/bpf_testmod.c | 10 ++++++++++
.../selftests/bpf/test_kmods/bpf_testmod_kfunc.h | 2 ++
5 files changed, 38 insertions(+)
diff --git a/tools/testing/selftests/bpf/prog_tests/kfunc_call.c b/tools/testing/selftests/bpf/prog_tests/kfunc_call.c
index 0063e60d6f2f..9b832c5961f5 100644
--- a/tools/testing/selftests/bpf/prog_tests/kfunc_call.c
+++ b/tools/testing/selftests/bpf/prog_tests/kfunc_call.c
@@ -63,6 +63,7 @@ static struct kfunc_test_params kfunc_tests[] = {
*/
SYSCALL_NULL_CTX_FAIL(kfunc_syscall_test_fail, -EINVAL, "processed 4 insns"),
SYSCALL_NULL_CTX_FAIL(kfunc_syscall_test_null_fail, -EINVAL, "processed 4 insns"),
+ TC_FAIL(kfunc_call_test_mem_len_fail_readonly, 0, "write into map forbidden"),
TC_FAIL(kfunc_call_test_get_mem_fail_rdonly, 0, "R0 cannot write into rdonly_mem"),
TC_FAIL(kfunc_call_test_get_mem_fail_use_after_free, 0, "invalid mem access 'scalar'"),
TC_FAIL(kfunc_call_test_get_mem_fail_oob, 0, "min value is outside of the allowed memory range"),
@@ -82,6 +83,7 @@ static struct kfunc_test_params kfunc_tests[] = {
TC_TEST(kfunc_call_test5_asm, 0),
TC_TEST(kfunc_call_test_ref_btf_id, 0),
TC_TEST(kfunc_call_test_get_mem, 42),
+ TC_TEST(kfunc_call_test_srcptr, 0),
SYSCALL_TEST(kfunc_syscall_test, 0),
SYSCALL_NULL_CTX_TEST(kfunc_syscall_test_null, 0),
TC_TEST(kfunc_call_test_static_unused_arg, 0),
diff --git a/tools/testing/selftests/bpf/progs/kfunc_call_fail.c b/tools/testing/selftests/bpf/progs/kfunc_call_fail.c
index 7e93f7fb1329..1ab85faaf8db 100644
--- a/tools/testing/selftests/bpf/progs/kfunc_call_fail.c
+++ b/tools/testing/selftests/bpf/progs/kfunc_call_fail.c
@@ -4,6 +4,8 @@
#include <bpf/bpf_helpers.h>
#include "../test_kmods/bpf_testmod_kfunc.h"
+static const char mem_len_rodata[] = "read-only data";
+
static struct bpf_spin_lock kfunc_call_lock SEC(".data.A");
SEC("?tc")
@@ -47,6 +49,14 @@ int kfunc_syscall_test_null_fail(struct syscall_test_args *args)
return 0;
}
+SEC("?tc")
+int kfunc_call_test_mem_len_fail_readonly(struct __sk_buff *skb)
+{
+ bpf_kfunc_call_test_mem_len_pass1((void *)mem_len_rodata,
+ sizeof(mem_len_rodata));
+ return 0;
+}
+
SEC("?tc")
int kfunc_call_test_get_mem_fail_rdonly(struct __sk_buff *skb)
{
diff --git a/tools/testing/selftests/bpf/progs/kfunc_call_test.c b/tools/testing/selftests/bpf/progs/kfunc_call_test.c
index 8e6560c31e78..fc862fce3f2f 100644
--- a/tools/testing/selftests/bpf/progs/kfunc_call_test.c
+++ b/tools/testing/selftests/bpf/progs/kfunc_call_test.c
@@ -5,6 +5,9 @@
#include "bpf_misc.h"
#include "../test_kmods/bpf_testmod_kfunc.h"
+static const char srcptr_rodata[] = "read-only source";
+static const struct prog_test_pass1 srcptr_struct_rodata = { .x0 = 1 };
+
static struct bpf_spin_lock kfunc_call_lock SEC(".data.A");
SEC("tc")
@@ -208,6 +211,17 @@ int kfunc_call_test_pass(struct __sk_buff *skb)
return 0;
}
+SEC("tc")
+int kfunc_call_test_srcptr(struct __sk_buff *skb)
+{
+ char stack_data[] = "read-write source";
+
+ bpf_kfunc_call_test_srcptr(srcptr_rodata, sizeof(srcptr_rodata));
+ bpf_kfunc_call_test_srcptr(stack_data, sizeof(stack_data));
+ bpf_kfunc_call_test_srcptr_struct(&srcptr_struct_rodata);
+ return 0;
+}
+
struct syscall_test_args {
__u8 data[16];
size_t size;
diff --git a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
index 6380f52f4dd2..87967c7236a7 100644
--- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
+++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
@@ -1024,6 +1024,8 @@ BTF_ID_FLAGS(func, bpf_kfunc_arena_args5_test)
BTF_ID_FLAGS(func, bpf_kfunc_arena_stack_arg_test)
BTF_ID_FLAGS(func, bpf_kfunc_arena_mixed_test)
BTF_ID_FLAGS(func, bpf_kfunc_call_test_mem_len_pass1)
+BTF_ID_FLAGS(func, bpf_kfunc_call_test_srcptr)
+BTF_ID_FLAGS(func, bpf_kfunc_call_test_srcptr_struct)
BTF_ID_FLAGS(func, bpf_kfunc_dynptr_test)
BTF_ID_FLAGS(func, bpf_kfunc_nested_acquire_nonzero_offset_test, KF_ACQUIRE)
BTF_ID_FLAGS(func, bpf_kfunc_nested_acquire_zero_offset_test, KF_ACQUIRE)
@@ -1527,6 +1529,14 @@ __bpf_kfunc void bpf_kfunc_call_test_mem_len_pass1(void *mem, int mem__sz)
{
}
+__bpf_kfunc void bpf_kfunc_call_test_srcptr(const void *src__srcptr, int src__sz)
+{
+}
+
+__bpf_kfunc void bpf_kfunc_call_test_srcptr_struct(const struct prog_test_pass1 *p__srcptr)
+{
+}
+
__bpf_kfunc void bpf_kfunc_call_test_mem_len_fail1(void *mem, int len)
{
}
diff --git a/tools/testing/selftests/bpf/test_kmods/bpf_testmod_kfunc.h b/tools/testing/selftests/bpf/test_kmods/bpf_testmod_kfunc.h
index 3b810f1e438f..6de080682618 100644
--- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod_kfunc.h
+++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod_kfunc.h
@@ -198,6 +198,8 @@ void bpf_kfunc_call_test_release(struct prog_test_ref_kfunc *p) __ksym;
void bpf_kfunc_call_test_ref(struct prog_test_ref_kfunc *p) __ksym;
void bpf_kfunc_call_test_mem_len_pass1(void *mem, int len) __ksym;
+void bpf_kfunc_call_test_srcptr(const void *src__srcptr, int src__sz) __ksym;
+void bpf_kfunc_call_test_srcptr_struct(const struct prog_test_pass1 *p__srcptr) __ksym;
__u64 bpf_kfunc_arena_arg_test(__u64 *val__arena) __ksym;
__u64 bpf_kfunc_arena_cap_test(__u64 *val__arena) __ksym;
__u64 bpf_kfunc_arena_cap_nullable_test(__u64 *val__arena__nullable) __ksym;
--
2.54.0
next prev parent reply other threads:[~2026-10-29 21:26 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-29 21:25 [PATCH bpf-next 0/8] bpf: Add user memory kfuncs Jiri Olsa
2026-10-29 21:25 ` [PATCH bpf-next 1/8] bpf: Add __srcptr kfunc argument suffix Jiri Olsa
2026-10-29 21:49 ` Andrii Nakryiko
2026-10-29 21:25 ` [PATCH bpf-next 2/8] bpf: Add user memory kfuncs Jiri Olsa
2026-10-29 22:00 ` Andrii Nakryiko
2026-10-29 22:12 ` bot+bpf-ci
2026-10-29 21:25 ` [PATCH bpf-next 3/8] selftests/bpf: Add get_procmap_info helper Jiri Olsa
2026-10-29 21:25 ` Jiri Olsa [this message]
2026-10-29 21:25 ` [PATCH bpf-next 5/8] selftests/bpf: Test user memory mmap kfuncs Jiri Olsa
2026-10-29 21:59 ` bot+bpf-ci
2026-10-29 21:25 ` [PATCH bpf-next 6/8] selftests/bpf: Test user memory page exec Jiri Olsa
2026-10-29 21:25 ` [PATCH bpf-next 7/8] selftests/bpf: Test bpf_copy_to_user kfunc Jiri Olsa
2026-10-29 21:25 ` [PATCH bpf-next 8/8] selftests/bpf: Test user memory kfunc errors Jiri Olsa
2026-10-29 21:59 ` bot+bpf-ci
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