From: Eduard Zingerman <eddyz87@xxxxxxxxx>
Verify that infinite loop detection logic separates states with
identical register states but different imprecise scalars spilled to
stack.
Signed-off-by: Eduard Zingerman <eddyz87@xxxxxxxxx>
---
.../selftests/bpf/progs/verifier_loops1.c | 24 +++++++++++++++++++
1 file changed, 24 insertions(+)
diff --git a/tools/testing/selftests/bpf/progs/verifier_loops1.c b/tools/testing/selftests/bpf/progs/verifier_loops1.c
index 71735dbf33d4..e07b43b78fd2 100644
--- a/tools/testing/selftests/bpf/progs/verifier_loops1.c
+++ b/tools/testing/selftests/bpf/progs/verifier_loops1.c
@@ -259,4 +259,28 @@ l0_%=: r2 += r1; \
" ::: __clobber_all);
}
+SEC("xdp")
+__success
+__naked void not_an_inifinite_loop(void)
+{
+ asm volatile (" \
+ call %[bpf_get_prandom_u32]; \
+ r0 &= 0xff; \
+ *(u64 *)(r10 - 8) = r0; \
+ r0 = 0; \
+loop_%=: \
+ r0 = *(u64 *)(r10 - 8); \
+ if r0 > 10 goto exit_%=; \
+ r0 += 1; \
+ *(u64 *)(r10 - 8) = r0; \
+ r0 = 0; \
+ goto loop_%=; \
+exit_%=: \
+ r0 = 0; \
+ exit; \
+" :
+ : __imm(bpf_get_prandom_u32)
+ : __clobber_all);
+}
+
char _license[] SEC("license") = "GPL";
--
2.42.1
