From f904c67876c42c14a108d7f80459ef59d900b8fc Mon Sep 17 00:00:00 2001 From: David Vernet Date: Fri, 2 Jun 2023 10:01:12 -0500 Subject: [PATCH] selftests/bpf: Add test for non-NULLable PTR_TO_BTF_IDs In a recent patch, we taught the verifier that trusted PTR_TO_BTF_ID can never be NULL. This prevents the verifier from incorrectly failing to load certain programs where it gets confused and thinks a reference isn't dropped because it incorrectly assumes that a branch exists in which a NULL PTR_TO_BTF_ID pointer is never released. This patch adds a testcase that verifies this cannot happen. Signed-off-by: David Vernet Acked-by: Stanislav Fomichev Link: https://lore.kernel.org/r/20230602150112.1494194-2-void@manifault.com Signed-off-by: Alexei Starovoitov --- .../selftests/bpf/prog_tests/cpumask.c | 1 + .../selftests/bpf/progs/cpumask_success.c | 24 +++++++++++++++++++ 2 files changed, 25 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/cpumask.c b/tools/testing/selftests/bpf/prog_tests/cpumask.c index cdf4acc18e4c..d89191440fb1 100644 --- a/tools/testing/selftests/bpf/prog_tests/cpumask.c +++ b/tools/testing/selftests/bpf/prog_tests/cpumask.c @@ -70,5 +70,6 @@ void test_cpumask(void) verify_success(cpumask_success_testcases[i]); } + RUN_TESTS(cpumask_success); RUN_TESTS(cpumask_failure); } diff --git a/tools/testing/selftests/bpf/progs/cpumask_success.c b/tools/testing/selftests/bpf/progs/cpumask_success.c index 2fcdd7f68ac7..602a88b03dbc 100644 --- a/tools/testing/selftests/bpf/progs/cpumask_success.c +++ b/tools/testing/selftests/bpf/progs/cpumask_success.c @@ -5,6 +5,7 @@ #include #include +#include "bpf_misc.h" #include "cpumask_common.h" char _license[] SEC("license") = "GPL"; @@ -426,3 +427,26 @@ int BPF_PROG(test_global_mask_rcu, struct task_struct *task, u64 clone_flags) return 0; } + +SEC("tp_btf/task_newtask") +__success +int BPF_PROG(test_refcount_null_tracking, struct task_struct *task, u64 clone_flags) +{ + struct bpf_cpumask *mask1, *mask2; + + mask1 = bpf_cpumask_create(); + mask2 = bpf_cpumask_create(); + + if (!mask1 || !mask2) + goto free_masks_return; + + bpf_cpumask_test_cpu(0, (const struct cpumask *)mask1); + bpf_cpumask_test_cpu(0, (const struct cpumask *)mask2); + +free_masks_return: + if (mask1) + bpf_cpumask_release(mask1); + if (mask2) + bpf_cpumask_release(mask2); + return 0; +}