* [PATCH stable 6.6 2/2] selftests/bpf: Add test to ensure kprobe_multi is not sleepable
2026-06-24 7:28 [PATCH stable 6.6 1/2] bpf: Reject sleepable kprobe_multi programs at attach time Shung-Hsi Yu
@ 2026-06-24 7:29 ` Shung-Hsi Yu
2026-06-25 10:41 ` [PATCH stable 6.6 1/2] bpf: Reject sleepable kprobe_multi programs at attach time Sasha Levin
1 sibling, 0 replies; 3+ messages in thread
From: Shung-Hsi Yu @ 2026-06-24 7:29 UTC (permalink / raw)
To: stable
Cc: Shung-Hsi Yu, Varun R Mallya, Kumar Kartikeya Dwivedi, Leon Hwang,
Jiri Olsa, Alexei Starovoitov
From: Varun R Mallya <varunrmallya@gmail.com>
commit c7cab53f9d5273f0cf2a26bdf178c4e074bdfb50 upstream.
Add a selftest to ensure that kprobe_multi programs cannot be attached
using the BPF_F_SLEEPABLE flag. This test succeeds when the kernel
rejects attachment of kprobe_multi when the BPF_F_SLEEPABLE flag is set.
Suggested-by: Leon Hwang <leon.hwang@linux.dev>
Signed-off-by: Varun R Mallya <varunrmallya@gmail.com>
Link: https://lore.kernel.org/r/20260408190137.101418-3-varunrmallya@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
[shung-hsi.yu: borrowed 'saved_error' variable from commit 00cdcd2900bd
("selftests/bpf: Don't use libbpf_get_error() in kprobe_multi_test"). ]
Signed-off-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
---
.../bpf/prog_tests/kprobe_multi_test.c | 34 +++++++++++++++++++
.../bpf/progs/kprobe_multi_sleepable.c | 25 ++++++++++++++
2 files changed, 59 insertions(+)
create mode 100644 tools/testing/selftests/bpf/progs/kprobe_multi_sleepable.c
diff --git a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c
index 4041cfa670eb..d41e140c3150 100644
--- a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c
+++ b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c
@@ -4,6 +4,7 @@
#include "trace_helpers.h"
#include "kprobe_multi_empty.skel.h"
#include "kprobe_multi_override.skel.h"
+#include "kprobe_multi_sleepable.skel.h"
#include "bpf/libbpf_internal.h"
#include "bpf/hashmap.h"
@@ -214,7 +215,9 @@ static void test_attach_api_syms(void)
static void test_attach_api_fails(void)
{
LIBBPF_OPTS(bpf_kprobe_multi_opts, opts);
+ LIBBPF_OPTS(bpf_test_run_opts, topts);
struct kprobe_multi *skel = NULL;
+ struct kprobe_multi_sleepable *sl_skel = NULL;
struct bpf_link *link = NULL;
unsigned long long addrs[2];
const char *syms[2] = {
@@ -222,6 +225,7 @@ static void test_attach_api_fails(void)
"bpf_fentry_test2",
};
__u64 cookies[2];
+ int saved_error, err;
addrs[0] = ksym_get_addr("bpf_fentry_test1");
addrs[1] = ksym_get_addr("bpf_fentry_test2");
@@ -300,9 +304,39 @@ static void test_attach_api_fails(void)
if (!ASSERT_EQ(libbpf_get_error(link), -EINVAL, "fail_5_error"))
goto cleanup;
+ /* fail_9 - sleepable kprobe multi should not attach */
+ sl_skel = kprobe_multi_sleepable__open();
+ if (!ASSERT_OK_PTR(sl_skel, "sleep_skel_open"))
+ goto cleanup;
+
+ sl_skel->bss->user_ptr = sl_skel;
+
+ err = bpf_program__set_flags(sl_skel->progs.handle_kprobe_multi_sleepable,
+ BPF_F_SLEEPABLE);
+ if (!ASSERT_OK(err, "sleep_skel_set_flags"))
+ goto cleanup;
+
+ err = kprobe_multi_sleepable__load(sl_skel);
+ if (!ASSERT_OK(err, "sleep_skel_load"))
+ goto cleanup;
+
+ link = bpf_program__attach_kprobe_multi_opts(sl_skel->progs.handle_kprobe_multi_sleepable,
+ "bpf_fentry_test1", NULL);
+ saved_error = -errno;
+
+ if (!ASSERT_ERR_PTR(link, "fail_9"))
+ goto cleanup;
+
+ if (!ASSERT_EQ(saved_error, -EINVAL, "fail_9_error"))
+ goto cleanup;
+
+ err = bpf_prog_test_run_opts(bpf_program__fd(sl_skel->progs.fentry), &topts);
+ ASSERT_OK(err, "bpf_prog_test_run_opts");
+
cleanup:
bpf_link__destroy(link);
kprobe_multi__destroy(skel);
+ kprobe_multi_sleepable__destroy(sl_skel);
}
static size_t symbol_hash(long key, void *ctx __maybe_unused)
diff --git a/tools/testing/selftests/bpf/progs/kprobe_multi_sleepable.c b/tools/testing/selftests/bpf/progs/kprobe_multi_sleepable.c
new file mode 100644
index 000000000000..932e1d9c72e2
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/kprobe_multi_sleepable.c
@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+void *user_ptr = 0;
+
+SEC("kprobe.multi")
+int handle_kprobe_multi_sleepable(struct pt_regs *ctx)
+{
+ int a, err;
+
+ err = bpf_copy_from_user(&a, sizeof(a), user_ptr);
+ barrier_var(a);
+ return err;
+}
+
+SEC("fentry/bpf_fentry_test1")
+int BPF_PROG(fentry)
+{
+ return 0;
+}
+
+char _license[] SEC("license") = "GPL";
--
2.54.0
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