kernel/linux.git/tools/lib/bpf/libbpf.c, branch v6.2.6

libbpf: Fix map creation flags sanitization

2023-03-10T08:28:05+00:00

[ Upstream commit 6920b08661e3ad829206078b5c9879b24aea8dfc ] As BPF_F_MMAPABLE flag is now conditionnaly set (by map_is_mmapable), it should not be toggled but disabled if not supported by kernel. Fixes: 4fcac46c7e10 ("libbpf: only add BPF_F_MMAPABLE flag for data maps with global vars") Signed-off-by: Ludovic L'Hours Acked-by: Jiri Olsa Link: https://lore.kernel.org/r/20230108182018.24433-1-ludovic.lhours@gmail.com Signed-off-by: Martin KaFai Lau Signed-off-by: Sasha Levin

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2022-11-29T21:04:52+00:00

tools/lib/bpf/ringbuf.c 927cbb478adf ("libbpf: Handle size overflow for ringbuf mmap") b486d19a0ab0 ("libbpf: checkpatch: Fixed code alignments in ringbuf.c") https://lore.kernel.org/all/20221121122707.44d1446a@canb.auug.org.au/ Signed-off-by: Jakub Kicinski

selftests/bpf: Workaround for llvm nop-4 bug

2022-11-22T21:34:08+00:00

Currently LLVM fails to recognize .data.* as data section and defaults to .text section. Later BPF backend tries to emit 4-byte NOP instruction which doesn't exist in BPF ISA and aborts. The fix for LLVM is pending: https://reviews.llvm.org/D138477 While waiting for the fix lets workaround the linked_list test case by using .bss.* prefix which is properly recognized by LLVM as BSS section. Fix libbpf to support .bss. prefix and adjust tests. Signed-off-by: Alexei Starovoitov

libbpf: Fixed various checkpatch issues in libbpf.c

2022-11-14T19:43:06+00:00

Fixed following checkpatch issues: WARNING: Block comments use a trailing */ on a separate line + * other BPF program's BTF object */ WARNING: Possible repeated word: 'be' + * name. This is important to be be able to find corresponding BTF ERROR: switch and case should be at the same indent + switch (ext->kcfg.sz) { + case 1: *(__u8 *)ext_val = value; break; + case 2: *(__u16 *)ext_val = value; break; + case 4: *(__u32 *)ext_val = value; break; + case 8: *(__u64 *)ext_val = value; break; + default: ERROR: trailing statements should be on next line + case 1: *(__u8 *)ext_val = value; break; ERROR: trailing statements should be on next line + case 2: *(__u16 *)ext_val = value; break; ERROR: trailing statements should be on next line + case 4: *(__u32 *)ext_val = value; break; ERROR: trailing statements should be on next line + case 8: *(__u64 *)ext_val = value; break; ERROR: code indent should use tabs where possible + }$ WARNING: please, no spaces at the start of a line + }$ WARNING: Block comments use a trailing */ on a separate line + * for faster search */ ERROR: code indent should use tabs where possible +^I^I^I^I^I^I &ext->kcfg.is_signed);$ WARNING: braces {} are not necessary for single statement blocks + if (err) { + return err; + } ERROR: code indent should use tabs where possible +^I^I^I^I sizeof(*obj->btf_modules), obj->btf_module_cnt + 1);$ Signed-off-by: Kang Minchul Signed-off-by: Andrii Nakryiko Acked-by: Stanislav Fomichev Link: https://lore.kernel.org/bpf/20221113190648.38556-3-tegongkang@gmail.com

libbpf: Use correct return pointer in attach_raw_tp

2022-11-14T19:36:55+00:00

We need to pass '*link' to final libbpf_get_error, because that one holds the return value, not 'link'. Fixes: 4fa5bcfe07f7 ("libbpf: Allow BPF program auto-attach handlers to bail out") Signed-off-by: Jiri Olsa Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20221114145257.882322-1-jolsa@kernel.org

libbpf: Hashmap interface update to allow both long and void* keys/values

2022-11-10T04:45:14+00:00

An update for libbpf's hashmap interface from void* -> void* to a polymorphic one, allowing both long and void* keys and values. This simplifies many use cases in libbpf as hashmaps there are mostly integer to integer. Perf copies hashmap implementation from libbpf and has to be updated as well. Changes to libbpf, selftests/bpf and perf are packed as a single commit to avoid compilation issues with any future bisect. Polymorphic interface is acheived by hiding hashmap interface functions behind auxiliary macros that take care of necessary type casts, for example: #define hashmap_cast_ptr(p) \ ({ \ _Static_assert((p) == NULL || sizeof(*(p)) == sizeof(long),\ #p " pointee should be a long-sized integer or a pointer"); \ (long *)(p); \ }) bool hashmap_find(const struct hashmap *map, long key, long *value); #define hashmap__find(map, key, value) \ hashmap_find((map), (long)(key), hashmap_cast_ptr(value)) - hashmap__find macro casts key and value parameters to long and long* respectively - hashmap_cast_ptr ensures that value pointer points to a memory of appropriate size. This hack was suggested by Andrii Nakryiko in [1]. This is a follow up for [2]. [1] https://lore.kernel.org/bpf/CAEf4BzZ8KFneEJxFAaNCCFPGqp20hSpS2aCj76uRk3-qZUH5xg@mail.gmail.com/ [2] https://lore.kernel.org/bpf/af1facf9-7bc8-8a3d-0db4-7b3f333589a2@meta.com/T/#m65b28f1d6d969fcd318b556db6a3ad499a42607d Signed-off-by: Eduard Zingerman Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20221109142611.879983-2-eddyz87@gmail.com

libbpf: Support new cgroup local storage

2022-10-26T06:19:19+00:00

Add support for new cgroup local storage. Acked-by: David Vernet Acked-by: Andrii Nakryiko Signed-off-by: Yonghong Song Link: https://lore.kernel.org/r/20221026042856.673989-1-yhs@fb.com Signed-off-by: Alexei Starovoitov

libbpf: only add BPF_F_MMAPABLE flag for data maps with global vars

2022-10-19T23:40:45+00:00

Teach libbpf to not add BPF_F_MMAPABLE flag unnecessarily for ARRAY maps that are backing data sections, if such data sections don't expose any variables to user-space. Exposed variables are those that have STB_GLOBAL or STB_WEAK ELF binding and correspond to BTF VAR's BTF_VAR_GLOBAL_ALLOCATED linkage. The overall idea is that if some data section doesn't have any variable that is exposed through BPF skeleton, then there is no reason to make such BPF array mmapable. Making BPF array mmapable is not a free no-op action, because BPF verifier doesn't allow users to put special objects (such as BPF spin locks, RB tree nodes, linked list nodes, kptrs, etc; anything that has a sensitive internal state that should not be modified arbitrarily from user space) into mmapable arrays, as there is no way to prevent user space from corrupting such sensitive state through direct memory access through memory-mapped region. By making sure that libbpf doesn't add BPF_F_MMAPABLE flag to BPF array maps corresponding to data sections that only have static variables (which are not supposed to be visible to user space according to libbpf and BPF skeleton rules), users now can have spinlocks, kptrs, etc in either default .bss/.data sections or custom .data.* sections (assuming there are no global variables in such sections). The only possible hiccup with this approach is the need to use global variables during BPF static linking, even if it's not intended to be shared with user space through BPF skeleton. To allow such scenarios, extend libbpf's STV_HIDDEN ELF visibility attribute handling to variables. Libbpf is already treating global hidden BPF subprograms as static subprograms and adjusts BTF accordingly to make BPF verifier verify such subprograms as static subprograms with preserving entire BPF verifier state between subprog calls. This patch teaches libbpf to treat global hidden variables as static ones and adjust BTF information accordingly as well. This allows to share variables between multiple object files during static linking, but still keep them internal to BPF program and not get them exposed through BPF skeleton. Note, that if the user has some advanced scenario where they absolutely need BPF_F_MMAPABLE flag on .data/.bss/.rodata BPF array map despite only having static variables, they still can achieve this by forcing it through explicit bpf_map__set_map_flags() API. Acked-by: Stanislav Fomichev Signed-off-by: Andrii Nakryiko Acked-by: Dave Marchevsky Link: https://lore.kernel.org/r/20221019002816.359650-3-andrii@kernel.org Signed-off-by: Alexei Starovoitov

libbpf: clean up and refactor BTF fixup step

2022-10-19T23:40:45+00:00

Refactor libbpf's BTF fixup step during BPF object open phase. The only functional change is that we now ignore BTF_VAR_GLOBAL_EXTERN variables during fix up, not just BTF_VAR_STATIC ones, which shouldn't cause any change in behavior as there shouldn't be any extern variable in data sections for valid BPF object anyways. Otherwise it's just collapsing two functions that have no reason to be separate, and switching find_elf_var_offset() helper to return entire symbol pointer, not just its offset. This will be used by next patch to get ELF symbol visibility. While refactoring, also "normalize" debug messages inside btf_fixup_datasec() to follow general libbpf style and print out data section name consistently, where it's available. Acked-by: Stanislav Fomichev Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20221019002816.359650-2-andrii@kernel.org Signed-off-by: Alexei Starovoitov

libbpf: Fix null-pointer dereference in find_prog_by_sec_insn()

2022-10-13T17:53:34+00:00

When there are no program sections, obj->programs is left unallocated, and find_prog_by_sec_insn()'s search lands on &obj->programs[0] == NULL, and will cause null-pointer dereference in the following access to prog->sec_idx. Guard the search with obj->nr_programs similar to what's being done in __bpf_program__iter() to prevent null-pointer access from happening. Fixes: db2b8b06423c ("libbpf: Support CO-RE relocations for multi-prog sections") Signed-off-by: Shung-Hsi Yu Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20221012022353.7350-4-shung-hsi.yu@suse.com