[PATCH bpf-next v3 4/4] selftests/bpf: new cases handled by 32->64 range refinements

Eduard Zingerman
2026-04-24T22:53:04Z

1. 32-bit range starts before 64-bit range's low bits in each block,
causing intersection to skip entire blocks.
2. 32-bit range crosses the U32_MAX/0 boundary, represented as s32
range crossing sign boundary.

Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
---
.../testing/selftests/bpf/progs/verifier_bounds.c | 80 ++++++++++++++++++++++
1 file changed, 80 insertions(+)

diff --git a/tools/testing/selftests/bpf/progs/verifier_bounds.c b/tools/testing/selftests/bpf/progs/verifier_bounds.c
index f0b3fbbbb627..5dd243e653c9 100644
--- a/tools/testing/selftests/bpf/progs/verifier_bounds.c
+++ b/tools/testing/selftests/bpf/progs/verifier_bounds.c
@@ -2187,4 +2187,84 @@ __naked void tnums_equal_impossible_constant(void *ctx)
: __clobber_all);
}

+/*
+ * 32-bit range starts before 64-bit range low bits in each 2^32 block.
+ *
+ * N*2^32 (N+1)*2^32 (N+2)*2^32 (N+3)*2^32
+ * ||----|=====|--|----------||----|=====|-------------||--|-|=====|-------------||
+ * |< b >| | |< b >| | |< b >|
+ * | | | |
+ * |<---------------+- a -+---------------->|
+ * | |
+ * |< t >| refined r0 range
+ *
+ * a = u64 [0x1'00000008, 0x3'00000001]
+ * b = u32 [2, 5]
+ * t = u64 [0x2'00000002, 0x2'00000005]
+ */
+SEC("socket")
+__success
+__flag(BPF_F_TEST_REG_INVARIANTS)
+__naked void deduce64_from_32_before_block_start(void)
+{
+ asm volatile (" \
+ call %[bpf_get_prandom_u32]; \
+ r1 = 0x100000008 ll; \
+ if r0 < r1 goto 2f; \
+ r1 = 0x300000001 ll; \
+ if r0 > r1 goto 2f; /* u64: [0x1'00000008, 0x3'00000001] */ \
+ if w0 < 2 goto 2f; \
+ if w0 > 5 goto 2f; /* u32: [2, 5] */ \
+ r2 = 0x200000002 ll; \
+ r3 = 0x200000005 ll; \
+ if r0 >= r2 goto 1f; /* should be always true */ \
+ r10 = 0; /* dead code */ \
+1: if r0 <= r3 goto 2f; /* should be always true */ \
+ r10 = 0; /* dead code */ \
+2: exit; \
+ "
+ :: __imm(bpf_get_prandom_u32)
+ : __clobber_all);
+}
+
+/*
+ * 32-bit range crossing U32_MAX / 0 boundary.
+ *
+ * N*2^32 (N+1)*2^32 (N+2)*2^32 (N+3)*2^32
+ * ||===|---------|------|===||===|----------------|===||===|---------|------|===||
+ * |b >| | |< b||b >| |< b||b >| | |< b|
+ * | | | |
+ * |<-----+----------------- a --------------+-------->|
+ * | |
+ * |<---------------- t ------------->| refined r0 range
+ *
+ * a = u64 [0x1'00000006, 0x2'FFFFFFEF]
+ * b = s32 [-16, 5] (u32 wrapping [0xFFFFFFF0, 0x00000005])
+ * t = u64 [0x1'FFFFFFF0, 0x2'00000005]
+ */
+SEC("socket")
+__success
+__flag(BPF_F_TEST_REG_INVARIANTS)
+__naked void deduce64_from_32_wrapping_32bit(void)
+{
+ asm volatile (" \
+ call %[bpf_get_prandom_u32]; \
+ r1 = 0x100000006 ll; \
+ if r0 < r1 goto 2f; \
+ r1 = 0x2ffffffef ll; \
+ if r0 > r1 goto 2f; /* u64: [0x1'00000006, 0x2'FFFFFFEF] */ \
+ if w0 s< -16 goto 2f; \
+ if w0 s> 5 goto 2f; /* s32: [-16, 5] */ \
+ r1 = 0x1fffffff0 ll; \
+ r2 = 0x200000005 ll; \
+ if r0 >= r1 goto 1f; /* should be always true */ \
+ r10 = 0; /* dead code */ \
+1: if r0 <= r2 goto 2f; /* should be always true */ \
+ r10 = 0; /* dead code */ \
+2: exit; \
+ "
+ :: __imm(bpf_get_prandom_u32)
+ : __clobber_all);
+}
+
char _license[] SEC("license") = "GPL";

--
2.53.0