From: Kaitao Cheng <[email protected]> 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 <[email protected]> --- tools/testing/selftests/bpf/prog_tests/kfunc_call.c | 2 ++ tools/testing/selftests/bpf/progs/kfunc_call_fail.c | 12 ++++++++++++ tools/testing/selftests/bpf/progs/kfunc_call_test.c | 12 ++++++++++++ tools/testing/selftests/bpf/test_kmods/bpf_testmod.c | 2 +- 4 files changed, 27 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/bpf/prog_tests/kfunc_call.c b/tools/testing/selftests/bpf/prog_tests/kfunc_call.c index 7af5560f2a08..2b39cc1b09f9 100644 --- a/tools/testing/selftests/bpf/prog_tests/kfunc_call.c +++ b/tools/testing/selftests/bpf/prog_tests/kfunc_call.c @@ -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), diff --git a/tools/testing/selftests/bpf/progs/kfunc_call_fail.c b/tools/testing/selftests/bpf/progs/kfunc_call_fail.c index 64b6a0b0ab1c..7e93f7fb1329 100644 --- a/tools/testing/selftests/bpf/progs/kfunc_call_fail.c +++ b/tools/testing/selftests/bpf/progs/kfunc_call_fail.c @@ -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; diff --git a/tools/testing/selftests/bpf/progs/kfunc_call_test.c b/tools/testing/selftests/bpf/progs/kfunc_call_test.c index 5edc51564f71..8e6560c31e78 100644 --- a/tools/testing/selftests/bpf/progs/kfunc_call_test.c +++ b/tools/testing/selftests/bpf/progs/kfunc_call_test.c @@ -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) { diff --git a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c index eb0f9b5e18d8..0585794606ed 100644 --- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c +++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c @@ -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) -- 2.50.1 (Apple Git-155)
