Re: [PATCH bpf-next 3/5] selftests/bpf: don't mask result of bpf_csum_diff() in test_verifier

From: Helge Deller
Date: Mon Oct 21 2024 - 09:02:06 EST


On 10/21/24 14:21, Puranjay Mohan wrote:
The bpf_csum_diff() helper has been fixed to return a 16-bit value for
all archs, so now we don't need to mask the result.

...
--- a/tools/testing/selftests/bpf/progs/verifier_array_access.c
+++ b/tools/testing/selftests/bpf/progs/verifier_array_access.c
@@ -368,8 +368,7 @@ __naked void a_read_only_array_2_1(void)
r4 = 0; \
r5 = 0; \
call %[bpf_csum_diff]; \
-l0_%=: r0 &= 0xffff; \
- exit; \
+l0_%=: exit; \

Instead of dropping the masking, would it make sense to
check here if (r0 >> 16) == 0 ?

Helge