Merge branch 'bpf-make-trusted-args-nullable'

Vadim Fedorenko says:

====================
bpf: make trusted args nullable

Current verifier checks for the arg to be nullable after checking for
certain pointer types. It prevents programs to pass NULL to kfunc args
even if they are marked as nullable. This patchset adjusts verifier and
changes bpf crypto kfuncs to allow null for IV parameter which is
optional for some ciphers. Benchmark shows ~4% improvements when there
is no need to initialise 0-sized dynptr.

v3:
- add special selftest for nullable parameters
v2:
- adjust kdoc accordingly
====================

Link: https://lore.kernel.org/r/20240613211817.1551967-1-vadfed@meta.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
index 0a09732cde4b..49f9a311e49b 100644
--- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
+++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
@@ -154,6 +154,11 @@ __bpf_kfunc void bpf_kfunc_common_test(void)
 {
 }
 
+__bpf_kfunc void bpf_kfunc_dynptr_test(struct bpf_dynptr *ptr,
+				       struct bpf_dynptr *ptr__nullable)
+{
+}
+
 struct bpf_testmod_btf_type_tag_1 {
 	int a;
 };
@@ -363,6 +368,7 @@ BTF_ID_FLAGS(func, bpf_iter_testmod_seq_new, KF_ITER_NEW)
 BTF_ID_FLAGS(func, bpf_iter_testmod_seq_next, KF_ITER_NEXT | KF_RET_NULL)
 BTF_ID_FLAGS(func, bpf_iter_testmod_seq_destroy, KF_ITER_DESTROY)
 BTF_ID_FLAGS(func, bpf_kfunc_common_test)
+BTF_ID_FLAGS(func, bpf_kfunc_dynptr_test)
 BTF_KFUNCS_END(bpf_testmod_common_kfunc_ids)
 
 static const struct btf_kfunc_id_set bpf_testmod_common_kfunc_set = {