From: Eduard Zingerman eddyz87@gmail.com
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@gmail.com --- .../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";