mirrors/linux
2
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2026-08-31 03:35:32 -04:00
Code Issues Packages Projects Releases Wiki Activity

selftests/bpf: Test module kfunc calls under spin lock

Browse Source 
The verifier uses kfunc registration flags to decide whether a kfunc may
be called while a BPF program holds a bpf_spin_lock.

Mark bpf_testmod_test_mod_kfunc() as KF_SPINLOCK_SAFE and verify that it
can be called while holding a bpf_spin_lock. Also attempt to call the
unmarked bpf_kfunc_trigger_ctx_check() under the lock and verify that the
program is rejected.

Signed-off-by: Kaitao Cheng <chengkaitao@kylinos.cn>
Acked-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/bpf/20260805153340.34776-4-kaitao.cheng@linux.dev
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
This commit is contained in:
Kaitao Cheng
2026-08-05 23:33:40 +08:00
committed by Kumar Kartikeya Dwivedi
parent 7619a0ee93
commit bca83aa31f
4 changed files with 27 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
tools/testing/selftests/bpf/prog_tests/kfunc_call.c
View File

@@ -71,8 +71,10 @@ static struct kfunc_test_params kfunc_tests[] = {
TC_FAIL(kfunc_call_test_get_mem_fail_not_const, 0, "is not a const"),
TC_FAIL(kfunc_call_test_mem_acquire_fail, 0, "acquire kernel function does not return PTR_TO_BTF_ID"),
TC_FAIL(kfunc_call_test_pointer_arg_type_mismatch, 0, "R1 expected pointer to ctx, but got scalar"),
TC_FAIL(kfunc_call_test_spin_lock_unsafe, 0, "function calls are not allowed while holding a lock"),
/* success cases */
TC_TEST(kfunc_call_test_spin_lock_safe, 0),
TC_TEST(kfunc_call_test1, 12),
TC_TEST(kfunc_call_test2, 3),
TC_TEST(kfunc_call_test4, -1234),

12
tools/testing/selftests/bpf/progs/kfunc_call_fail.c
View File

@@ -4,6 +4,18 @@
#include <bpf/bpf_helpers.h>
#include "../test_kmods/bpf_testmod_kfunc.h"
static struct bpf_spin_lock kfunc_call_lock SEC(".data.A");
SEC("?tc")
int kfunc_call_test_spin_lock_unsafe(struct __sk_buff *skb)
{
bpf_spin_lock(&kfunc_call_lock);
bpf_kfunc_trigger_ctx_check();
bpf_spin_unlock(&kfunc_call_lock);
return 0;
}
struct syscall_test_args {
__u8 data[16];
size_t size;

12
tools/testing/selftests/bpf/progs/kfunc_call_test.c
View File

@@ -5,6 +5,18 @@
#include "bpf_misc.h"
#include "../test_kmods/bpf_testmod_kfunc.h"
static struct bpf_spin_lock kfunc_call_lock SEC(".data.A");
SEC("tc")
int kfunc_call_test_spin_lock_safe(struct __sk_buff *skb)
{
bpf_spin_lock(&kfunc_call_lock);
bpf_testmod_test_mod_kfunc(42);
bpf_spin_unlock(&kfunc_call_lock);
return 0;
}
SEC("tc")
int kfunc_call_test5(struct __sk_buff *skb)
{

2
tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
View File

@@ -1384,7 +1384,7 @@ __bpf_kfunc void bpf_kfunc_trigger_ctx_check(void)
}
BTF_KFUNCS_START(bpf_testmod_check_kfunc_ids)
BTF_ID_FLAGS(func, bpf_testmod_test_mod_kfunc)
BTF_ID_FLAGS(func, bpf_testmod_test_mod_kfunc, KF_SPINLOCK_SAFE)
BTF_ID_FLAGS(func, bpf_kfunc_call_test1)
BTF_ID_FLAGS(func, bpf_kfunc_call_test2)
BTF_ID_FLAGS(func, bpf_kfunc_call_test3)