diff --git a/tools/testing/selftests/bpf/progs/iters.c b/tools/testing/selftests/bpf/progs/iters.c index 62d7df9e80be..c6699159dacd 100644 --- a/tools/testing/selftests/bpf/progs/iters.c +++ b/tools/testing/selftests/bpf/progs/iters.c @@ -2149,4 +2149,43 @@ __naked int stack_misc_vs_scalar_in_a_loop(void) ); } +__used +static int loop_cb5(int i, __u64 *ctx) +{ + /* unsafe on a second iteration */ + small_arr[*ctx] = i; + *ctx = 100500; + return 0; +} + +SEC("raw_tp") +__flag(BPF_F_TEST_STATE_FREQ) +__failure __msg("memory access is {{.*}} and is outside of the object of size 64") +__naked void loop_counter_precision_2nd_iter(void) +{ + asm volatile ( + "call %[bpf_get_prandom_u32];" + "*(u64 *)(r10 - 8) = 0;" + "r1 = 2;" + "if r0 == 42 goto +1;" + "r1 = 1;" + "r2 = loop_cb5 ll;" + "r3 = r10;" + "r3 += -8;" + "r4 = 0;" + /* + * Explore with nr_loops=1 on a first path and nr_loops=2 on a second path. + * Buggy verifier did not propagate r1 precision properly, + * and thus checkpoints created for nr_loops=1 case matched nr_loops=2 case. + */ + "call %[bpf_loop];" + "r0 = 0;" + "exit;" + : + : __imm(bpf_loop), + __imm(bpf_get_prandom_u32) + : __clobber_all + ); +} + char _license[] SEC("license") = "GPL";