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2024-03-25selftests/bpf: Fix flaky test btf_map_in_map/lookup_updateYonghong Song
Recently, I frequently hit the following test failure: [root@arch-fb-vm1 bpf]# ./test_progs -n 33/1 test_lookup_update:PASS:skel_open 0 nsec [...] test_lookup_update:PASS:sync_rcu 0 nsec test_lookup_update:FAIL:map1_leak inner_map1 leaked! #33/1 btf_map_in_map/lookup_update:FAIL #33 btf_map_in_map:FAIL In the test, after map is closed and then after two rcu grace periods, it is assumed that map_id is not available to user space. But the above assumption cannot be guaranteed. After zero or one or two rcu grace periods in different siturations, the actual freeing-map-work is put into a workqueue. Later on, when the work is dequeued, the map will be actually freed. See bpf_map_put() in kernel/bpf/syscall.c. By using workqueue, there is no ganrantee that map will be actually freed after a couple of rcu grace periods. This patch removed such map leak detection and then the test can pass consistently. Signed-off-by: Yonghong Song <yonghong.song@linux.dev> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20240322061353.632136-1-yonghong.song@linux.dev
2023-02-16selftests/bpf: Use bpf_{btf,link,map,prog}_get_info_by_fd()Ilya Leoshkevich
Use the new type-safe wrappers around bpf_obj_get_info_by_fd(). Fix a prog/map mixup in prog_holds_map(). Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20230214231221.249277-6-iii@linux.ibm.com
2021-01-12selftests/bpf: Sync RCU before unloading bpf_testmodAndrii Nakryiko
If some of the subtests use module BTFs through ksyms, they will cause bpf_prog to take a refcount on bpf_testmod module, which will prevent it from successfully unloading. Module's refcnt is decremented when bpf_prog is freed, which generally happens in RCU callback. So we need to trigger syncronize_rcu() in the kernel, which can be achieved nicely with membarrier(MEMBARRIER_CMD_SHARED) or membarrier(MEMBARRIER_CMD_GLOBAL) syscall. So do that in kernel_sync_rcu() and make it available to other test inside the test_progs. This synchronize_rcu() is called before attempting to unload bpf_testmod. Fixes: 9f7fa225894c ("selftests/bpf: Add bpf_testmod kernel module for testing") Suggested-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Acked-by: Hao Luo <haoluo@google.com> Link: https://lore.kernel.org/bpf/20210112075520.4103414-5-andrii@kernel.org
2020-10-11bpf, selftests: Add test for different array inner map sizeDaniel Borkmann
Extend the "diff_size" subtest to also include a non-inlined array map variant where dynamic inner #elems are possible. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20201010234006.7075-5-daniel@iogearbox.net
2020-08-28bpf: selftests: Add test for different inner map sizeMartin KaFai Lau
This patch tests the inner map size can be different for reuseport_sockarray but has to be the same for arraymap. A new subtest "diff_size" is added for this. The existing test is moved to a subtest "lookup_update". Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20200828011819.1970825-1-kafai@fb.com
2020-07-30selftests/bpf: Extend map-in-map selftest to detect memory leaksAndrii Nakryiko
Add test validating that all inner maps are released properly after skeleton is destroyed. To ensure determinism, trigger kernel-side synchronize_rcu() before checking map existence by their IDs. Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Song Liu <songliubraving@fb.com> Link: https://lore.kernel.org/bpf/20200729040913.2815687-2-andriin@fb.com
2020-04-28libbpf: Add BTF-defined map-in-map supportAndrii Nakryiko
As discussed at LPC 2019 ([0]), this patch brings (a quite belated) support for declarative BTF-defined map-in-map support in libbpf. It allows to define ARRAY_OF_MAPS and HASH_OF_MAPS BPF maps without any user-space initialization code involved. Additionally, it allows to initialize outer map's slots with references to respective inner maps at load time, also completely declaratively. Despite a weak type system of C, the way BTF-defined map-in-map definition works, it's actually quite hard to accidentally initialize outer map with incompatible inner maps. This being C, of course, it's still possible, but even that would be caught at load time and error returned with helpful debug log pointing exactly to the slot that failed to be initialized. As an example, here's a rather advanced HASH_OF_MAPS declaration and initialization example, filling slots #0 and #4 with two inner maps: #include <bpf/bpf_helpers.h> struct inner_map { __uint(type, BPF_MAP_TYPE_ARRAY); __uint(max_entries, 1); __type(key, int); __type(value, int); } inner_map1 SEC(".maps"), inner_map2 SEC(".maps"); struct outer_hash { __uint(type, BPF_MAP_TYPE_HASH_OF_MAPS); __uint(max_entries, 5); __uint(key_size, sizeof(int)); __array(values, struct inner_map); } outer_hash SEC(".maps") = { .values = { [0] = &inner_map2, [4] = &inner_map1, }, }; Here's the relevant part of libbpf debug log showing pretty clearly of what's going on with map-in-map initialization: libbpf: .maps relo #0: for 6 value 0 rel.r_offset 96 name 260 ('inner_map1') libbpf: .maps relo #0: map 'outer_arr' slot [0] points to map 'inner_map1' libbpf: .maps relo #1: for 7 value 32 rel.r_offset 112 name 249 ('inner_map2') libbpf: .maps relo #1: map 'outer_arr' slot [2] points to map 'inner_map2' libbpf: .maps relo #2: for 7 value 32 rel.r_offset 144 name 249 ('inner_map2') libbpf: .maps relo #2: map 'outer_hash' slot [0] points to map 'inner_map2' libbpf: .maps relo #3: for 6 value 0 rel.r_offset 176 name 260 ('inner_map1') libbpf: .maps relo #3: map 'outer_hash' slot [4] points to map 'inner_map1' libbpf: map 'inner_map1': created successfully, fd=4 libbpf: map 'inner_map2': created successfully, fd=5 libbpf: map 'outer_hash': created successfully, fd=7 libbpf: map 'outer_hash': slot [0] set to map 'inner_map2' fd=5 libbpf: map 'outer_hash': slot [4] set to map 'inner_map1' fd=4 Notice from the log above that fd=6 (not logged explicitly) is used for inner "prototype" map, necessary for creation of outer map. It is destroyed immediately after outer map is created. See also included selftest with some extra comments explaining extra details of usage. Additionally, similar initialization syntax and libbpf functionality can be used to do initialization of BPF_PROG_ARRAY with references to BPF sub-programs. This can be done in follow up patches, if there will be a demand for this. [0] https://linuxplumbersconf.org/event/4/contributions/448/ Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Toke Høiland-Jørgensen <toke@redhat.com> Link: https://lore.kernel.org/bpf/20200429002739.48006-4-andriin@fb.com