From 91957791663f49561848c40e982061799b8f86b0 Mon Sep 17 00:00:00 2001 From: Eduard Zingerman Date: Fri, 4 Sep 2026 17:05:59 -0700 Subject: selftests/bpf: precision of a NULL global subprogram BTF_ID argument Check that mark_chain_precision() is called for a NULL pointer passed as an __arg_trusted __arg_nullable argument of a global subprogram. Signed-off-by: Eduard Zingerman Link: https://lore.kernel.org/r/20260904-register-is-null-precise-fixes-v1-8-0f5a360ff15d@gmail.com Signed-off-by: Alexei Starovoitov --- .../selftests/bpf/progs/verifier_global_ptr_args.c | 24 ++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/tools/testing/selftests/bpf/progs/verifier_global_ptr_args.c b/tools/testing/selftests/bpf/progs/verifier_global_ptr_args.c index 0bdeb7bc4687..a3d2af8dc839 100644 --- a/tools/testing/selftests/bpf/progs/verifier_global_ptr_args.c +++ b/tools/testing/selftests/bpf/progs/verifier_global_ptr_args.c @@ -56,6 +56,30 @@ int trusted_task_arg_nullable(void *ctx) return res; } +/* + * Check that the verifier does not use checkpoints created + * on path with r1 == 0 to prune path with r1 != 0. + */ +SEC("?tp_btf/task_newtask") +__failure +__flag(BPF_F_TEST_STATE_FREQ) +__msg("R1 type=scalar expected=ptr_, trusted_ptr_, rcu_ptr_") +__naked int null_btf_id_arg_global_subprog(void) +{ + asm volatile ( + "call %[bpf_get_prandom_u32];" + "r1 = 42;" + "if r0 > 42 goto 1f;" + "r1 = 0;" + "1:" + "call subprog_trusted_task_nullable;" + "r0 = 0;" + "exit;" + : + : __imm(bpf_get_prandom_u32) + : __clobber_all); +} + __weak int subprog_trusted_task_nonnull(struct task_struct *task __arg_trusted) { return task->pid + task->tgid; -- cgit v1.2.3