kernel/linux.git/tools/testing/selftests/bpf/verifier/map_kptr.c, branch v6.7

selftests/bpf: Add F_NEEDS_EFFICIENT_UNALIGNED_ACCESS to some tests

2023-07-05T12:34:23+00:00

Some verifier tests were missing F_NEEDS_EFFICIENT_UNALIGNED_ACCESS, which made the test fail. Add the flag where needed. Signed-off-by: Björn Töpel Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20230705113926.751791-2-bjorn@kernel.org

bpf: Remove bpf_kfunc_call_test_kptr_get() test kfunc

2023-04-16T15:51:24+00:00

We've managed to improve the UX for kptrs significantly over the last 9 months. All of the prior main use cases, struct bpf_cpumask *, struct task_struct *, and struct cgroup *, have all been updated to be synchronized mainly using RCU. In other words, their KF_ACQUIRE kfunc calls are all KF_RCU, and the pointers themselves are MEM_RCU and can be accessed in an RCU read region in BPF. In a follow-on change, we'll be removing the KF_KPTR_GET kfunc flag. This patch prepares for that by removing the bpf_kfunc_call_test_kptr_get() kfunc, and all associated selftests. Signed-off-by: David Vernet Link: https://lore.kernel.org/r/20230416084928.326135-2-void@manifault.com Signed-off-by: Alexei Starovoitov

bpf: Introduce kptr_rcu.

2023-03-03T16:42:20+00:00

The life time of certain kernel structures like 'struct cgroup' is protected by RCU. Hence it's safe to dereference them directly from __kptr tagged pointers in bpf maps. The resulting pointer is MEM_RCU and can be passed to kfuncs that expect KF_RCU. Derefrence of other kptr-s returns PTR_UNTRUSTED. For example: struct map_value { struct cgroup __kptr *cgrp; }; SEC("tp_btf/cgroup_mkdir") int BPF_PROG(test_cgrp_get_ancestors, struct cgroup *cgrp_arg, const char *path) { struct cgroup *cg, *cg2; cg = bpf_cgroup_acquire(cgrp_arg); // cg is PTR_TRUSTED and ref_obj_id > 0 bpf_kptr_xchg(&v->cgrp, cg); cg2 = v->cgrp; // This is new feature introduced by this patch. // cg2 is PTR_MAYBE_NULL | MEM_RCU. // When cg2 != NULL, it's a valid cgroup, but its percpu_ref could be zero if (cg2) bpf_cgroup_ancestor(cg2, level); // safe to do. } Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann Acked-by: Tejun Heo Acked-by: David Vernet Link: https://lore.kernel.org/bpf/20230303041446.3630-4-alexei.starovoitov@gmail.com

bpf: Prepare prog_test_struct kfuncs for runtime tests

2022-05-11T23:57:27+00:00

In an effort to actually test the refcounting logic at runtime, add a refcount_t member to prog_test_ref_kfunc and use it in selftests to verify and test the whole logic more exhaustively. The kfunc calls for prog_test_member do not require runtime refcounting, as they are only used for verifier selftests, not during runtime execution. Hence, their implementation now has a WARN_ON_ONCE as it is not meant to be reachable code at runtime. It is strictly used in tests triggering failure cases in the verifier. bpf_kfunc_call_memb_release is called from map free path, since prog_test_member is embedded in map value for some verifier tests, so we skip WARN_ON_ONCE for it. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20220511194654.765705-3-memxor@gmail.com Signed-off-by: Alexei Starovoitov

selftests/bpf: Add verifier tests for kptr

2022-04-26T03:26:44+00:00

Reuse bpf_prog_test functions to test the support for PTR_TO_BTF_ID in BPF map case, including some tests that verify implementation sanity and corner cases. Signed-off-by: Kumar Kartikeya Dwivedi Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20220424214901.2743946-13-memxor@gmail.com