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2022-01-05libbpf: Support repeated legacy kprobes on same functionQiang Wang1-1/+4
If repeated legacy kprobes on same function in one process, libbpf will register using the same probe name and got -EBUSY error. So append index to the probe name format to fix this problem. Co-developed-by: Chengming Zhou <[email protected]> Signed-off-by: Qiang Wang <[email protected]> Signed-off-by: Chengming Zhou <[email protected]> Signed-off-by: Andrii Nakryiko <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2022-01-05libbpf: Use probe_name for legacy kprobeQiang Wang1-1/+1
Fix a bug in commit 46ed5fc33db9, which wrongly used the func_name instead of probe_name to register legacy kprobe. Fixes: 46ed5fc33db9 ("libbpf: Refactor and simplify legacy kprobe code") Co-developed-by: Chengming Zhou <[email protected]> Signed-off-by: Qiang Wang <[email protected]> Signed-off-by: Chengming Zhou <[email protected]> Signed-off-by: Andrii Nakryiko <[email protected]> Tested-by: Hengqi Chen <[email protected]> Reviewed-by: Hengqi Chen <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2022-01-05libbpf: Deprecate bpf_perf_event_read_simple() APIChristy Lee1-8/+14
With perf_buffer__poll() and perf_buffer__consume() APIs available, there is no reason to expose bpf_perf_event_read_simple() API to users. If users need custom perf buffer, they could re-implement the function. Mark bpf_perf_event_read_simple() and move the logic to a new static function so it can still be called by other functions in the same file. [0] Closes: https://github.com/libbpf/libbpf/issues/310 Signed-off-by: Christy Lee <[email protected]> Signed-off-by: Andrii Nakryiko <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-12-28libbpf: Improve LINUX_VERSION_CODE detectionAndrii Nakryiko1-1/+26
Ubuntu reports incorrect kernel version through uname(), which on older kernels leads to kprobe BPF programs failing to load due to the version check mismatch. Accommodate Ubuntu's quirks with LINUX_VERSION_CODE by using Ubuntu-specific /proc/version_code to fetch major/minor/patch versions to form LINUX_VERSION_CODE. While at it, consolide libbpf's kernel version detection code between libbpf.c and libbpf_probes.c. [0] Closes: https://github.com/libbpf/libbpf/issues/421 Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Acked-by: Yonghong Song <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-12-14libbpf: Avoid reading past ELF data section end when copying licenseAndrii Nakryiko1-1/+4
Fix possible read beyond ELF "license" data section if the license string is not properly zero-terminated. Use the fact that libbpf_strlcpy never accesses the (N-1)st byte of the source string because it's replaced with '\0' anyways. If this happens, it's a violation of contract between libbpf and a user, but not handling this more robustly upsets CIFuzz, so given the fix is trivial, let's fix the potential issue. Fixes: 9fc205b413b3 ("libbpf: Add sane strncpy alternative and use it internally") Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-12-14libbpf: Auto-bump RLIMIT_MEMLOCK if kernel needs it for BPFAndrii Nakryiko1-38/+9
The need to increase RLIMIT_MEMLOCK to do anything useful with BPF is one of the first extremely frustrating gotchas that all new BPF users go through and in some cases have to learn it a very hard way. Luckily, starting with upstream Linux kernel version 5.11, BPF subsystem dropped the dependency on memlock and uses memcg-based memory accounting instead. Unfortunately, detecting memcg-based BPF memory accounting is far from trivial (as can be evidenced by this patch), so in practice most BPF applications still do unconditional RLIMIT_MEMLOCK increase. As we move towards libbpf 1.0, it would be good to allow users to forget about RLIMIT_MEMLOCK vs memcg and let libbpf do the sensible adjustment automatically. This patch paves the way forward in this matter. Libbpf will do feature detection of memcg-based accounting, and if detected, will do nothing. But if the kernel is too old, just like BCC, libbpf will automatically increase RLIMIT_MEMLOCK on behalf of user application ([0]). As this is technically a breaking change, during the transition period applications have to opt into libbpf 1.0 mode by setting LIBBPF_STRICT_AUTO_RLIMIT_MEMLOCK bit when calling libbpf_set_strict_mode(). Libbpf allows to control the exact amount of set RLIMIT_MEMLOCK limit with libbpf_set_memlock_rlim_max() API. Passing 0 will make libbpf do nothing with RLIMIT_MEMLOCK. libbpf_set_memlock_rlim_max() has to be called before the first bpf_prog_load(), bpf_btf_load(), or bpf_object__load() call, otherwise it has no effect and will return -EBUSY. [0] Closes: https://github.com/libbpf/libbpf/issues/369 Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-12-14libbpf: Add sane strncpy alternative and use it internallyAndrii Nakryiko1-5/+3
strncpy() has a notoriously error-prone semantics which makes GCC complain about it a lot (and quite often completely completely falsely at that). Instead of pleasing GCC all the time (-Wno-stringop-truncation is unfortunately only supported by GCC, so it's a bit too messy to just enable it in Makefile), add libbpf-internal libbpf_strlcpy() helper which follows what FreeBSD's strlcpy() does and what most people would expect from strncpy(): copies up to N-1 first bytes from source string into destination string and ensures zero-termination afterwards. Replace all the relevant uses of strncpy/strncat/memcpy in libbpf with libbpf_strlcpy(). This also fixes the issue reported by Emmanuel Deloget in xsk.c where memcpy() could access source string beyond its end. Fixes: 2f6324a3937f8 (libbpf: Support shared umems between queues and devices) Reported-by: Emmanuel Deloget <[email protected]> Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-12-10Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextJakub Kicinski1-198/+451
Andrii Nakryiko says: ==================== bpf-next 2021-12-10 v2 We've added 115 non-merge commits during the last 26 day(s) which contain a total of 182 files changed, 5747 insertions(+), 2564 deletions(-). The main changes are: 1) Various samples fixes, from Alexander Lobakin. 2) BPF CO-RE support in kernel and light skeleton, from Alexei Starovoitov. 3) A batch of new unified APIs for libbpf, logging improvements, version querying, etc. Also a batch of old deprecations for old APIs and various bug fixes, in preparation for libbpf 1.0, from Andrii Nakryiko. 4) BPF documentation reorganization and improvements, from Christoph Hellwig and Dave Tucker. 5) Support for declarative initialization of BPF_MAP_TYPE_PROG_ARRAY in libbpf, from Hengqi Chen. 6) Verifier log fixes, from Hou Tao. 7) Runtime-bounded loops support with bpf_loop() helper, from Joanne Koong. 8) Extend branch record capturing to all platforms that support it, from Kajol Jain. 9) Light skeleton codegen improvements, from Kumar Kartikeya Dwivedi. 10) bpftool doc-generating script improvements, from Quentin Monnet. 11) Two libbpf v0.6 bug fixes, from Shuyi Cheng and Vincent Minet. 12) Deprecation warning fix for perf/bpf_counter, from Song Liu. 13) MAX_TAIL_CALL_CNT unification and MIPS build fix for libbpf, from Tiezhu Yang. 14) BTF_KING_TYPE_TAG follow-up fixes, from Yonghong Song. 15) Selftests fixes and improvements, from Ilya Leoshkevich, Jean-Philippe Brucker, Jiri Olsa, Maxim Mikityanskiy, Tirthendu Sarkar, Yucong Sun, and others. * https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (115 commits) libbpf: Add "bool skipped" to struct bpf_map libbpf: Fix typo in btf__dedup@LIBBPF_0.0.2 definition bpftool: Switch bpf_object__load_xattr() to bpf_object__load() selftests/bpf: Remove the only use of deprecated bpf_object__load_xattr() selftests/bpf: Add test for libbpf's custom log_buf behavior selftests/bpf: Replace all uses of bpf_load_btf() with bpf_btf_load() libbpf: Deprecate bpf_object__load_xattr() libbpf: Add per-program log buffer setter and getter libbpf: Preserve kernel error code and remove kprobe prog type guessing libbpf: Improve logging around BPF program loading libbpf: Allow passing user log setting through bpf_object_open_opts libbpf: Allow passing preallocated log_buf when loading BTF into kernel libbpf: Add OPTS-based bpf_btf_load() API libbpf: Fix bpf_prog_load() log_buf logic for log_level 0 samples/bpf: Remove unneeded variable bpf: Remove redundant assignment to pointer t selftests/bpf: Fix a compilation warning perf/bpf_counter: Use bpf_map_create instead of bpf_create_map samples: bpf: Fix 'unknown warning group' build warning on Clang samples: bpf: Fix xdp_sample_user.o linking with Clang ... ==================== Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Jakub Kicinski <[email protected]>
2021-12-10libbpf: Add "bool skipped" to struct bpf_mapShuyi Cheng1-3/+8
Fix error: "failed to pin map: Bad file descriptor, path: /sys/fs/bpf/_rodata_str1_1." In the old kernel, the global data map will not be created, see [0]. So we should skip the pinning of the global data map to avoid bpf_object__pin_maps returning error. Therefore, when the map is not created, we mark “map->skipped" as true and then check during relocation and during pinning. Fixes: 16e0c35c6f7a ("libbpf: Load global data maps lazily on legacy kernels") Signed-off-by: Shuyi Cheng <[email protected]> Signed-off-by: Andrii Nakryiko <[email protected]>
2021-12-10libbpf: Deprecate bpf_object__load_xattr()Andrii Nakryiko1-13/+10
Deprecate non-extensible bpf_object__load_xattr() in v0.8 ([0]). With log_level control through bpf_object_open_opts or bpf_program__set_log_level(), we are finally at the point where bpf_object__load_xattr() doesn't provide any functionality that can't be accessed through other (better) ways. The other feature, target_btf_path, is also controllable through bpf_object_open_opts. [0] Closes: https://github.com/libbpf/libbpf/issues/289 Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-12-10libbpf: Add per-program log buffer setter and getterAndrii Nakryiko1-17/+75
Allow to set user-provided log buffer on a per-program basis ([0]). This gives great deal of flexibility in terms of which programs are loaded with logging enabled and where corresponding logs go. Log buffer set with bpf_program__set_log_buf() overrides kernel_log_buf and kernel_log_size settings set at bpf_object open time through bpf_object_open_opts, if any. Adjust bpf_object_load_prog_instance() logic to not perform own log buf allocation and load retry if custom log buffer is provided by the user. [0] Closes: https://github.com/libbpf/libbpf/issues/418 Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-12-10libbpf: Preserve kernel error code and remove kprobe prog type guessingAndrii Nakryiko1-17/+2
Instead of rewriting error code returned by the kernel of prog load with libbpf-sepcific variants pass through the original error. There is now also no need to have a backup generic -LIBBPF_ERRNO__LOAD fallback error as bpf_prog_load() guarantees that errno will be properly set no matter what. Also drop a completely outdated and pretty useless BPF_PROG_TYPE_KPROBE guess logic. It's not necessary and neither it's helpful in modern BPF applications. Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-12-10libbpf: Improve logging around BPF program loadingAndrii Nakryiko1-19/+19
Add missing "prog '%s': " prefixes in few places and use consistently markers for beginning and end of program load logs. Here's an example of log output: libbpf: prog 'handler': BPF program load failed: Permission denied libbpf: -- BEGIN PROG LOAD LOG --- arg#0 reference type('UNKNOWN ') size cannot be determined: -22 ; out1 = in1; 0: (18) r1 = 0xffffc9000cdcc000 2: (61) r1 = *(u32 *)(r1 +0) ... 81: (63) *(u32 *)(r4 +0) = r5 R1_w=map_value(id=0,off=16,ks=4,vs=20,imm=0) R4=map_value(id=0,off=400,ks=4,vs=16,imm=0) invalid access to map value, value_size=16 off=400 size=4 R4 min value is outside of the allowed memory range processed 63 insns (limit 1000000) max_states_per_insn 0 total_states 0 peak_states 0 mark_read 0 -- END PROG LOAD LOG -- libbpf: failed to load program 'handler' libbpf: failed to load object 'test_skeleton' The entire verifier log, including BEGIN and END markers are now always youtput during a single print callback call. This should make it much easier to post-process or parse it, if necessary. It's not an explicit API guarantee, but it can be reasonably expected to stay like that. Also __bpf_object__open is renamed to bpf_object_open() as it's always an adventure to find the exact function that implements bpf_object's open phase, so drop the double underscored and use internal libbpf naming convention. Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-12-10libbpf: Allow passing user log setting through bpf_object_open_optsAndrii Nakryiko1-1/+23
Allow users to provide their own custom log_buf, log_size, and log_level at bpf_object level through bpf_object_open_opts. This log_buf will be used during BTF loading. Subsequent patch will use same log_buf during BPF program loading, unless overriden at per-bpf_program level. When such custom log_buf is provided, libbpf won't be attempting retrying loading of BTF to try to provide its own log buffer to capture kernel's error log output. User is responsible to provide big enough buffer, otherwise they run a risk of getting -ENOSPC error from the bpf() syscall. See also comments in bpf_object_open_opts regarding log_level and log_buf interactions. Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-12-03libbpf: Reduce bpf_core_apply_relo_insn() stack usage.Alexei Starovoitov1-1/+3
Reduce bpf_core_apply_relo_insn() stack usage and bump BPF_CORE_SPEC_MAX_LEN limit back to 64. Fixes: 29db4bea1d10 ("bpf: Prepare relo_core.c for kernel duty.") Signed-off-by: Alexei Starovoitov <[email protected]> Signed-off-by: Andrii Nakryiko <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-12-02libbpf: Add API to get/set log_level at per-program levelAndrii Nakryiko1-0/+14
Add bpf_program__set_log_level() and bpf_program__log_level() to fetch and adjust log_level sent during BPF_PROG_LOAD command. This allows to selectively request more or less verbose output in BPF verifier log. Also bump libbpf version to 0.7 and make these APIs the first in v0.7. Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-12-02libbpf: Support init of inner maps in light skeleton.Alexei Starovoitov1-3/+3
Add ability to initialize inner maps in light skeleton. Signed-off-by: Alexei Starovoitov <[email protected]> Signed-off-by: Andrii Nakryiko <[email protected]> Acked-by: Andrii Nakryiko <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-12-02libbpf: Use CO-RE in the kernel in light skeleton.Alexei Starovoitov1-30/+79
Without lskel the CO-RE relocations are processed by libbpf before any other work is done. Instead, when lskel is needed, remember relocation as RELO_CORE kind. Then when loader prog is generated for a given bpf program pass CO-RE relos of that program to gen loader via bpf_gen__record_relo_core(). The gen loader will remember them as-is and pass it later as-is into the kernel. The normal libbpf flow is to process CO-RE early before call relos happen. In case of gen_loader the core relos have to be added to other relos to be copied together when bpf static function is appended in different places to other main bpf progs. During the copy the append_subprog_relos() will adjust insn_idx for normal relos and for RELO_CORE kind too. When that is done each struct reloc_desc has good relos for specific main prog. Signed-off-by: Alexei Starovoitov <[email protected]> Signed-off-by: Andrii Nakryiko <[email protected]> Acked-by: Andrii Nakryiko <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-12-02libbpf: Cleanup struct bpf_core_cand.Andrii Nakryiko1-13/+17
Remove two redundant fields from struct bpf_core_cand. Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Signed-off-by: Andrii Nakryiko <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-12-02bpf: Define enum bpf_core_relo_kind as uapi.Alexei Starovoitov1-1/+1
enum bpf_core_relo_kind is generated by llvm and processed by libbpf. It's a de-facto uapi. With CO-RE in the kernel the bpf_core_relo_kind values become uapi de-jure. Also rename them with BPF_CORE_ prefix to distinguish from conflicting names in bpf_core_read.h. The enums bpf_field_info_kind, bpf_type_id_kind, bpf_type_info_kind, bpf_enum_value_kind are passing different values from bpf program into llvm. Signed-off-by: Alexei Starovoitov <[email protected]> Signed-off-by: Andrii Nakryiko <[email protected]> Acked-by: Andrii Nakryiko <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-11-30libbpf: Remove duplicate assignmentsMehrdad Arshad Rad1-1/+0
There is a same action when load_attr.attach_btf_id is initialized. Signed-off-by: Mehrdad Arshad Rad <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-11-28libbpf: Support static initialization of BPF_MAP_TYPE_PROG_ARRAYHengqi Chen1-33/+121
Support static initialization of BPF_MAP_TYPE_PROG_ARRAY with a syntax similar to map-in-map initialization ([0]): SEC("socket") int tailcall_1(void *ctx) { return 0; } struct { __uint(type, BPF_MAP_TYPE_PROG_ARRAY); __uint(max_entries, 2); __uint(key_size, sizeof(__u32)); __array(values, int (void *)); } prog_array_init SEC(".maps") = { .values = { [1] = (void *)&tailcall_1, }, }; Here's the relevant part of libbpf debug log showing what's going on with prog-array initialization: libbpf: sec '.relsocket': collecting relocation for section(3) 'socket' libbpf: sec '.relsocket': relo #0: insn #2 against 'prog_array_init' libbpf: prog 'entry': found map 0 (prog_array_init, sec 4, off 0) for insn #0 libbpf: .maps relo #0: for 3 value 0 rel->r_offset 32 name 53 ('tailcall_1') libbpf: .maps relo #0: map 'prog_array_init' slot [1] points to prog 'tailcall_1' libbpf: map 'prog_array_init': created successfully, fd=5 libbpf: map 'prog_array_init': slot [1] set to prog 'tailcall_1' fd=6 [0] Closes: https://github.com/libbpf/libbpf/issues/354 Signed-off-by: Hengqi Chen <[email protected]> Signed-off-by: Andrii Nakryiko <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-11-26libbpf: Don't call libc APIs with NULL pointersAndrii Nakryiko1-3/+7
Sanitizer complains about qsort(), bsearch(), and memcpy() being called with NULL pointer. This can only happen when the associated number of elements is zero, so no harm should be done. But still prevent this from happening to keep sanitizer runs clean from extra noise. Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-11-25libbpf: Use bpf_map_create() consistently internallyAndrii Nakryiko1-24/+6
Remove all the remaining uses of to-be-deprecated bpf_create_map*() APIs. Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-11-25libbpf: Unify low-level map creation APIs w/ new bpf_map_create()Andrii Nakryiko1-17/+16
Mark the entire zoo of low-level map creation APIs for deprecation in libbpf 0.7 ([0]) and introduce a new bpf_map_create() API that is OPTS-based (and thus future-proof) and matches the BPF_MAP_CREATE command name. While at it, ensure that gen_loader sends map_extra field. Also remove now unneeded btf_key_type_id/btf_value_type_id logic that libbpf is doing anyways. [0] Closes: https://github.com/libbpf/libbpf/issues/282 Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-11-25libbpf: Load global data maps lazily on legacy kernelsAndrii Nakryiko1-4/+30
Load global data maps lazily, if kernel is too old to support global data. Make sure that programs are still correct by detecting if any of the to-be-loaded programs have relocation against any of such maps. This allows to solve the issue ([0]) with bpf_printk() and Clang generating unnecessary and unreferenced .rodata.strX.Y sections, but it also goes further along the CO-RE lines, allowing to have a BPF object in which some code can work on very old kernels and relies only on BPF maps explicitly, while other BPF programs might enjoy global variable support. If such programs are correctly set to not load at runtime on old kernels, bpf_object will load and function correctly now. [0] https://lore.kernel.org/bpf/CAK-59YFPU3qO+_pXWOH+c1LSA=8WA1yabJZfREjOEXNHAqgXNg@mail.gmail.com/ Fixes: aed659170a31 ("libbpf: Support multiple .rodata.* and .data.* BPF maps") Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Acked-by: Song Liu <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-11-19libbpf: Change bpf_program__set_extra_flags to bpf_program__set_flagsFlorent Revest1-2/+2
bpf_program__set_extra_flags has just been introduced so we can still change it without breaking users. This new interface is a bit more flexible (for example if someone wants to clear a flag). Signed-off-by: Florent Revest <[email protected]> Signed-off-by: Andrii Nakryiko <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-11-19libbpf: Add runtime APIs to query libbpf versionAndrii Nakryiko1-0/+19
Libbpf provided LIBBPF_MAJOR_VERSION and LIBBPF_MINOR_VERSION macros to check libbpf version at compilation time. This doesn't cover all the needs, though, because version of libbpf that application is compiled against doesn't necessarily match the version of libbpf at runtime, especially if libbpf is used as a shared library. Add libbpf_major_version() and libbpf_minor_version() returning major and minor versions, respectively, as integers. Also add a convenience libbpf_version_string() for various tooling using libbpf to print out libbpf version in a human-readable form. Currently it will return "v0.6", but in the future it can contains some extra information, so the format itself is not part of a stable API and shouldn't be relied upon. Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Acked-by: John Fastabend <[email protected]> Acked-by: Toke Høiland-Jørgensen <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-11-18Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski1-2/+2
Signed-off-by: Jakub Kicinski <[email protected]>
2021-11-12libbpf: Perform map fd cleanup for gen_loader in case of errorKumar Kartikeya Dwivedi1-2/+2
Alexei reported a fd leak issue in gen loader (when invoked from bpftool) [0]. When adding ksym support, map fd allocation was moved from stack to loader map, however I missed closing these fds (relevant when cleanup label is jumped to on error). For the success case, the allocated fd is returned in loader ctx, hence this problem is not noticed. Make three changes, first MAX_USED_MAPS in MAX_FD_ARRAY_SZ instead of MAX_USED_PROGS, the braino was not a problem until now for this case as we didn't try to close map fds (otherwise use of it would have tried closing 32 additional fds in ksym btf fd range). Then, do a cleanup for all nr_maps fds in cleanup label code, so that in case of error all temporary map fds from bpf_gen__map_create are closed. Then, adjust the cleanup label to only generate code for the required number of program and map fds. To trim code for remaining program fds, lay out prog_fd array in stack in the end, so that we can directly skip the remaining instances. Still stack size remains same, since changing that would require changes in a lot of places (including adjustment of stack_off macro), so nr_progs_sz variable is only used to track required number of iterations (and jump over cleanup size calculated from that), stack offset calculation remains unaffected. The difference for test_ksyms_module.o is as follows: libbpf: //prog cleanup iterations: before = 34, after = 5 libbpf: //maps cleanup iterations: before = 64, after = 2 Also, move allocation of gen->fd_array offset to bpf_gen__init. Since offset can now be 0, and we already continue even if add_data returns 0 in case of failure, we do not need to distinguish between 0 offset and failure case 0, as we rely on bpf_gen__finish to check errors. We can also skip check for gen->fd_array in add_*_fd functions, since bpf_gen__init will take care of it. [0]: https://lore.kernel.org/bpf/CAADnVQJ6jSitKSNKyxOrUzwY2qDRX0sPkJ=VLGHuCLVJ=qOt9g@mail.gmail.com Fixes: 18f4fccbf314 ("libbpf: Update gen_loader to emit BTF_KIND_FUNC relocations") Reported-by: Alexei Starovoitov <[email protected]> Signed-off-by: Kumar Kartikeya Dwivedi <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-11-11libbpf: Support BTF_KIND_TYPE_TAGYonghong Song1-1/+30
Add libbpf support for BTF_KIND_TYPE_TAG. Signed-off-by: Yonghong Song <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Acked-by: Andrii Nakryiko <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-11-11libbpf: Make perf_buffer__new() use OPTS-based interfaceAndrii Nakryiko1-15/+55
Add new variants of perf_buffer__new() and perf_buffer__new_raw() that use OPTS-based options for future extensibility ([0]). Given all the currently used API names are best fits, re-use them and use ___libbpf_override() approach and symbol versioning to preserve ABI and source code compatibility. struct perf_buffer_opts and struct perf_buffer_raw_opts are kept as well, but they are restructured such that they are OPTS-based when used with new APIs. For struct perf_buffer_raw_opts we keep few fields intact, so we have to also preserve the memory location of them both when used as OPTS and for legacy API variants. This is achieved with anonymous padding for OPTS "incarnation" of the struct. These pads can be eventually used for new options. [0] Closes: https://github.com/libbpf/libbpf/issues/311 Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-11-11libbpf: Add ability to get/set per-program load flagsAndrii Nakryiko1-0/+14
Add bpf_program__flags() API to retrieve prog_flags that will be (or were) supplied to BPF_PROG_LOAD command. Also add bpf_program__set_extra_flags() API to allow to set *extra* flags, in addition to those determined by program's SEC() definition. Such flags are logically OR'ed with libbpf-derived flags. Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-11-07libbpf: Free up resources used by inner map definitionAndrii Nakryiko1-1/+4
It's not enough to just free(map->inner_map), as inner_map itself can have extra memory allocated, like map name. Fixes: 646f02ffdd49 ("libbpf: Add BTF-defined map-in-map support") Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Reviewed-by: Hengqi Chen <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-11-07libbpf: Stop using to-be-deprecated APIsAndrii Nakryiko1-4/+9
Remove all the internal uses of libbpf APIs that are slated to be deprecated in v0.7. Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-11-07libbpf: Remove internal use of deprecated bpf_prog_load() variantsAndrii Nakryiko1-81/+38
Remove all the internal uses of bpf_load_program_xattr(), which is slated for deprecation in v0.7. Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-11-07libbpf: Unify low-level BPF_PROG_LOAD APIs into bpf_prog_load()Andrii Nakryiko1-26/+25
Add a new unified OPTS-based low-level API for program loading, bpf_prog_load() ([0]). bpf_prog_load() accepts few "mandatory" parameters as input arguments (program type, name, license, instructions) and all the other optional (as in not required to specify for all types of BPF programs) fields into struct bpf_prog_load_opts. This makes all the other non-extensible APIs variant for BPF_PROG_LOAD obsolete and they are slated for deprecation in libbpf v0.7: - bpf_load_program(); - bpf_load_program_xattr(); - bpf_verify_program(). Implementation-wise, internal helper libbpf__bpf_prog_load is refactored to become a public bpf_prog_load() API. struct bpf_prog_load_params used internally is replaced by public struct bpf_prog_load_opts. Unfortunately, while conceptually all this is pretty straightforward, the biggest complication comes from the already existing bpf_prog_load() *high-level* API, which has nothing to do with BPF_PROG_LOAD command. We try really hard to have a new API named bpf_prog_load(), though, because it maps naturally to BPF_PROG_LOAD command. For that, we rename old bpf_prog_load() into bpf_prog_load_deprecated() and mark it as COMPAT_VERSION() for shared library users compiled against old version of libbpf. Statically linked users and shared lib users compiled against new version of libbpf headers will get "rerouted" to bpf_prog_deprecated() through a macro helper that decides whether to use new or old bpf_prog_load() based on number of input arguments (see ___libbpf_overload in libbpf_common.h). To test that existing bpf_prog_load()-using code compiles and works as expected, I've compiled and ran selftests as is. I had to remove (locally) selftest/bpf/Makefile -Dbpf_prog_load=bpf_prog_test_load hack because it was conflicting with the macro-based overload approach. I don't expect anyone else to do something like this in practice, though. This is testing-specific way to replace bpf_prog_load() calls with special testing variant of it, which adds extra prog_flags value. After testing I kept this selftests hack, but ensured that we use a new bpf_prog_load_deprecated name for this. This patch also marks bpf_prog_load() and bpf_prog_load_xattr() as deprecated. bpf_object interface has to be used for working with struct bpf_program. Libbpf doesn't support loading just a bpf_program. The silver lining is that when we get to libbpf 1.0 all these complication will be gone and we'll have one clean bpf_prog_load() low-level API with no backwards compatibility hackery surrounding it. [0] Closes: https://github.com/libbpf/libbpf/issues/284 Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-11-03libbpf: Deprecate bpf_program__load() APIAndrii Nakryiko1-14/+22
Mark bpf_program__load() as deprecated ([0]) since v0.6. Also rename few internal program loading bpf_object helper functions to have more consistent naming. [0] Closes: https://github.com/libbpf/libbpf/issues/301 Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-11-03libbpf: Improve ELF relo sanitizationAndrii Nakryiko1-5/+19
Add few sanity checks for relocations to prevent div-by-zero and out-of-bounds array accesses in libbpf. Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Acked-by: Yonghong Song <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-11-03libbpf: Fix section counting logicAndrii Nakryiko1-4/+4
e_shnum does include section #0 and as such is exactly the number of ELF sections that we need to allocate memory for to use section indices as array indices. Fix the off-by-one error. This is purely accounting fix, previously we were overallocating one too many array items. But no correctness errors otherwise. Fixes: 25bbbd7a444b ("libbpf: Remove assumptions about uniqueness of .rodata/.data/.bss maps") Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Acked-by: Yonghong Song <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-11-03libbpf: Validate that .BTF and .BTF.ext sections contain dataAndrii Nakryiko1-0/+4
.BTF and .BTF.ext ELF sections should have SHT_PROGBITS type and contain data. If they are not, ELF is invalid or corrupted, so bail out. Otherwise this can lead to data->d_buf being NULL and SIGSEGV later on. Reported by oss-fuzz project. Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Acked-by: Yonghong Song <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-11-03libbpf: Improve sanity checking during BTF fix upAndrii Nakryiko1-3/+2
If BTF is corrupted DATASEC's variable type ID might be incorrect. Prevent this easy to detect situation with extra NULL check. Reported by oss-fuzz project. Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Acked-by: Yonghong Song <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-11-03libbpf: Detect corrupted ELF symbols sectionAndrii Nakryiko1-1/+1
Prevent divide-by-zero if ELF is corrupted and has zero sh_entsize. Reported by oss-fuzz project. Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Acked-by: Yonghong Song <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-11-01Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextJakub Kicinski1-442/+799
Alexei Starovoitov says: ==================== pull-request: bpf-next 2021-11-01 We've added 181 non-merge commits during the last 28 day(s) which contain a total of 280 files changed, 11791 insertions(+), 5879 deletions(-). The main changes are: 1) Fix bpf verifier propagation of 64-bit bounds, from Alexei. 2) Parallelize bpf test_progs, from Yucong and Andrii. 3) Deprecate various libbpf apis including af_xdp, from Andrii, Hengqi, Magnus. 4) Improve bpf selftests on s390, from Ilya. 5) bloomfilter bpf map type, from Joanne. 6) Big improvements to JIT tests especially on Mips, from Johan. 7) Support kernel module function calls from bpf, from Kumar. 8) Support typeless and weak ksym in light skeleton, from Kumar. 9) Disallow unprivileged bpf by default, from Pawan. 10) BTF_KIND_DECL_TAG support, from Yonghong. 11) Various bpftool cleanups, from Quentin. * https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (181 commits) libbpf: Deprecate AF_XDP support kbuild: Unify options for BTF generation for vmlinux and modules selftests/bpf: Add a testcase for 64-bit bounds propagation issue. bpf: Fix propagation of signed bounds from 64-bit min/max into 32-bit. bpf: Fix propagation of bounds from 64-bit min/max into 32-bit and var_off. selftests/bpf: Fix also no-alu32 strobemeta selftest bpf: Add missing map_delete_elem method to bloom filter map selftests/bpf: Add bloom map success test for userspace calls bpf: Add alignment padding for "map_extra" + consolidate holes bpf: Bloom filter map naming fixups selftests/bpf: Add test cases for struct_ops prog bpf: Add dummy BPF STRUCT_OPS for test purpose bpf: Factor out helpers for ctx access checking bpf: Factor out a helper to prepare trampoline for struct_ops prog selftests, bpf: Fix broken riscv build riscv, libbpf: Add RISC-V (RV64) support to bpf_tracing.h tools, build: Add RISC-V to HOSTARCH parsing riscv, bpf: Increase the maximum number of iterations selftests, bpf: Add one test for sockmap with strparser selftests, bpf: Fix test_txmsg_ingress_parser error ... ==================== Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Jakub Kicinski <[email protected]>
2021-10-28libbpf: Use O_CLOEXEC uniformly when opening fdsKumar Kartikeya Dwivedi1-3/+3
There are some instances where we don't use O_CLOEXEC when opening an fd, fix these up. Otherwise, it is possible that a parallel fork causes these fds to leak into a child process on execve. Signed-off-by: Kumar Kartikeya Dwivedi <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Acked-by: Andrii Nakryiko <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-10-28libbpf: Add typeless ksym support to gen_loaderKumar Kartikeya Dwivedi1-8/+5
This uses the bpf_kallsyms_lookup_name helper added in previous patches to relocate typeless ksyms. The return value ENOENT can be ignored, and the value written to 'res' can be directly stored to the insn, as it is overwritten to 0 on lookup failure. For repeating symbols, we can simply copy the previously populated bpf_insn. Also, we need to take care to not close fds for typeless ksym_desc, so reuse the 'off' member's space to add a marker for typeless ksym and use that to skip them in cleanup_relos. We add a emit_ksym_relo_log helper that avoids duplicating common logging instructions between typeless and weak ksym (for future commit). Signed-off-by: Kumar Kartikeya Dwivedi <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-10-28libbpf: Add "map_extra" as a per-map-type extra flagJoanne Koong1-5/+33
This patch adds the libbpf infrastructure for supporting a per-map-type "map_extra" field, whose definition will be idiosyncratic depending on map type. For example, for the bloom filter map, the lower 4 bits of map_extra is used to denote the number of hash functions. Please note that until libbpf 1.0 is here, the "bpf_create_map_params" struct is used as a temporary means for propagating the map_extra field to the kernel. Signed-off-by: Joanne Koong <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Acked-by: Andrii Nakryiko <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-10-27libbpf: Deprecate bpf_objects_listJoe Burton1-1/+7
Add a flag to `enum libbpf_strict_mode' to disable the global `bpf_objects_list', preventing race conditions when concurrent threads call bpf_object__open() or bpf_object__close(). bpf_object__next() will return NULL if this option is set. Callers may achieve the same workflow by tracking bpf_objects in application code. [0] Closes: https://github.com/libbpf/libbpf/issues/293 Signed-off-by: Joe Burton <[email protected]> Signed-off-by: Andrii Nakryiko <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-10-25libbpf: Use __BYTE_ORDER__Ilya Leoshkevich1-2/+2
Use the compiler-defined __BYTE_ORDER__ instead of the libc-defined __BYTE_ORDER for consistency. Signed-off-by: Ilya Leoshkevich <[email protected]> Signed-off-by: Andrii Nakryiko <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]
2021-10-25libbpf: Deprecate multi-instance bpf_program APIsAndrii Nakryiko1-9/+13
Schedule deprecation of a set of APIs that are related to multi-instance bpf_programs: - bpf_program__set_prep() ([0]); - bpf_program__{set,unset}_instance() ([1]); - bpf_program__nth_fd(). These APIs are obscure, very niche, and don't seem to be used much in practice. bpf_program__set_prep() is pretty useless for anything but the simplest BPF programs, as it doesn't allow to adjust BPF program load attributes, among other things. In short, it already bitrotted and will bitrot some more if not removed. With bpf_program__insns() API, which gives access to post-processed BPF program instructions of any given entry-point BPF program, it's now possible to do whatever necessary adjustments were possible with set_prep() API before, but also more. Given any such use case is automatically an advanced use case, requiring users to stick to low-level bpf_prog_load() APIs and managing their own prog FDs is reasonable. [0] Closes: https://github.com/libbpf/libbpf/issues/299 [1] Closes: https://github.com/libbpf/libbpf/issues/300 Signed-off-by: Andrii Nakryiko <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]> Link: https://lore.kernel.org/bpf/[email protected]