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17 hourslibbpf: Use proper errno value in nlattrAnton Protopopov
[ Upstream commit fd5fd538a1f4b34cee6823ba0ddda2f7a55aca96 ] Return value of the validate_nla() function can be propagated all the way up to users of libbpf API. In case of error this libbpf version of validate_nla returns -1 which will be seen as -EPERM from user's point of view. Instead, return a more reasonable -EINVAL. Fixes: bbf48c18ee0c ("libbpf: add error reporting in XDP") Suggested-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20250510182011.2246631-1-a.s.protopopov@gmail.com Signed-off-by: Sasha Levin <sashal@kernel.org>
17 hoursbpf: Fix uninitialized values in BPF_{CORE,PROBE}_READAnton Protopopov
[ Upstream commit 41d4ce6df3f4945341ec509a840cc002a413b6cc ] With the latest LLVM bpf selftests build will fail with the following error message: progs/profiler.inc.h:710:31: error: default initialization of an object of type 'typeof ((parent_task)->real_cred->uid.val)' (aka 'const unsigned int') leaves the object uninitialized and is incompatible with C++ [-Werror,-Wdefault-const-init-unsafe] 710 | proc_exec_data->parent_uid = BPF_CORE_READ(parent_task, real_cred, uid.val); | ^ tools/testing/selftests/bpf/tools/include/bpf/bpf_core_read.h:520:35: note: expanded from macro 'BPF_CORE_READ' 520 | ___type((src), a, ##__VA_ARGS__) __r; \ | ^ This happens because BPF_CORE_READ (and other macro) declare the variable __r using the ___type macro which can inherit const modifier from intermediate types. Fix this by using __typeof_unqual__, when supported. (And when it is not supported, the problem shouldn't appear, as older compilers haven't complained.) Fixes: 792001f4f7aa ("libbpf: Add user-space variants of BPF_CORE_READ() family of macros") Fixes: a4b09a9ef945 ("libbpf: Add non-CO-RE variants of BPF_CORE_READ() macro family") Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20250502193031.3522715-1-a.s.protopopov@gmail.com Signed-off-by: Sasha Levin <sashal@kernel.org>
17 hourslibbpf: Use proper errno value in linkerAnton Protopopov
[ Upstream commit 358b1c0f56ebb6996fcec7dcdcf6bae5dcbc8b6c ] Return values of the linker_append_sec_data() and the linker_append_elf_relos() functions are propagated all the way up to users of libbpf API. In some error cases these functions return -1 which will be seen as -EPERM from user's point of view. Instead, return a more reasonable -EINVAL. Fixes: faf6ed321cf6 ("libbpf: Add BPF static linker APIs") Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20250430120820.2262053-1-a.s.protopopov@gmail.com Signed-off-by: Sasha Levin <sashal@kernel.org>
17 hoursUse thread-safe function pointer in libbpf_printJonathan Wiepert
[ Upstream commit 91dbac4076537b464639953c055c460d2bdfc7ea ] This patch fixes a thread safety bug where libbpf_print uses the global variable storing the print function pointer rather than the local variable that had the print function set via __atomic_load_n. Fixes: f1cb927cdb62 ("libbpf: Ensure print callback usage is thread-safe") Signed-off-by: Jonathan Wiepert <jonathan.wiepert@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Mykyta Yatsenko <mykyta.yatsenko5@gmail.com> Link: https://lore.kernel.org/bpf/20250424221457.793068-1-jonathan.wiepert@gmail.com Signed-off-by: Sasha Levin <sashal@kernel.org>
17 hourslibbpf: Remove sample_period init in perf_bufferTao Chen
[ Upstream commit 64821d25f05ac468d435e61669ae745ce5a633ea ] It seems that sample_period is not used in perf buffer. Actually, only wakeup_events are meaningful to enable events aggregation for wakeup notification. Remove sample_period setting code to avoid confusion. Fixes: fb84b8224655 ("libbpf: add perf buffer API") Signed-off-by: Tao Chen <chen.dylane@linux.dev> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Acked-by: Namhyung Kim <namhyung@kernel.org> Link: https://lore.kernel.org/bpf/20250423163901.2983689-1-chen.dylane@linux.dev Signed-off-by: Sasha Levin <sashal@kernel.org>
17 hourslibbpf: Fix event name too long errorFeng Yang
[ Upstream commit 4dde20b1aa85d69c4281eaac9a7cfa7d2b62ecf0 ] When the binary path is excessively long, the generated probe_name in libbpf exceeds the kernel's MAX_EVENT_NAME_LEN limit (64 bytes). This causes legacy uprobe event attachment to fail with error code -22. The fix reorders the fields to place the unique ID before the name. This ensures that even if truncation occurs via snprintf, the unique ID remains intact, preserving event name uniqueness. Additionally, explicit checks with MAX_EVENT_NAME_LEN are added to enforce length constraints. Before Fix: ./test_progs -t attach_probe/kprobe-long_name ...... libbpf: failed to add legacy kprobe event for 'bpf_testmod_looooooooooooooooooooooooooooooong_name+0x0': -EINVAL libbpf: prog 'handle_kprobe': failed to create kprobe 'bpf_testmod_looooooooooooooooooooooooooooooong_name+0x0' perf event: -EINVAL test_attach_kprobe_long_event_name:FAIL:attach_kprobe_long_event_name unexpected error: -22 test_attach_probe:PASS:uprobe_ref_ctr_cleanup 0 nsec #13/11 attach_probe/kprobe-long_name:FAIL #13 attach_probe:FAIL ./test_progs -t attach_probe/uprobe-long_name ...... libbpf: failed to add legacy uprobe event for /root/linux-bpf/bpf-next/tools/testing/selftests/bpf/test_progs:0x13efd9: -EINVAL libbpf: prog 'handle_uprobe': failed to create uprobe '/root/linux-bpf/bpf-next/tools/testing/selftests/bpf/test_progs:0x13efd9' perf event: -EINVAL test_attach_uprobe_long_event_name:FAIL:attach_uprobe_long_event_name unexpected error: -22 #13/10 attach_probe/uprobe-long_name:FAIL #13 attach_probe:FAIL After Fix: ./test_progs -t attach_probe/uprobe-long_name #13/10 attach_probe/uprobe-long_name:OK #13 attach_probe:OK Summary: 1/1 PASSED, 0 SKIPPED, 0 FAILED ./test_progs -t attach_probe/kprobe-long_name #13/11 attach_probe/kprobe-long_name:OK #13 attach_probe:OK Summary: 1/1 PASSED, 0 SKIPPED, 0 FAILED Fixes: 46ed5fc33db9 ("libbpf: Refactor and simplify legacy kprobe code") Fixes: cc10623c6810 ("libbpf: Add legacy uprobe attaching support") Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com> Signed-off-by: Feng Yang <yangfeng@kylinos.cn> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20250417014848.59321-2-yangfeng59949@163.com Signed-off-by: Sasha Levin <sashal@kernel.org>
17 hourslibbpf: Fix buffer overflow in bpf_object__init_progViktor Malik
[ Upstream commit ee684de5c1b0ac01821320826baec7da93f3615b ] As shown in [1], it is possible to corrupt a BPF ELF file such that arbitrary BPF instructions are loaded by libbpf. This can be done by setting a symbol (BPF program) section offset to a large (unsigned) number such that <section start + symbol offset> overflows and points before the section data in the memory. Consider the situation below where: - prog_start = sec_start + symbol_offset <-- size_t overflow here - prog_end = prog_start + prog_size prog_start sec_start prog_end sec_end | | | | v v v v .....................|################################|............ The report in [1] also provides a corrupted BPF ELF which can be used as a reproducer: $ readelf -S crash Section Headers: [Nr] Name Type Address Offset Size EntSize Flags Link Info Align ... [ 2] uretprobe.mu[...] PROGBITS 0000000000000000 00000040 0000000000000068 0000000000000000 AX 0 0 8 $ readelf -s crash Symbol table '.symtab' contains 8 entries: Num: Value Size Type Bind Vis Ndx Name ... 6: ffffffffffffffb8 104 FUNC GLOBAL DEFAULT 2 handle_tp Here, the handle_tp prog has section offset ffffffffffffffb8, i.e. will point before the actual memory where section 2 is allocated. This is also reported by AddressSanitizer: ================================================================= ==1232==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7c7302fe0000 at pc 0x7fc3046e4b77 bp 0x7ffe64677cd0 sp 0x7ffe64677490 READ of size 104 at 0x7c7302fe0000 thread T0 #0 0x7fc3046e4b76 in memcpy (/lib64/libasan.so.8+0xe4b76) #1 0x00000040df3e in bpf_object__init_prog /src/libbpf/src/libbpf.c:856 #2 0x00000040df3e in bpf_object__add_programs /src/libbpf/src/libbpf.c:928 #3 0x00000040df3e in bpf_object__elf_collect /src/libbpf/src/libbpf.c:3930 #4 0x00000040df3e in bpf_object_open /src/libbpf/src/libbpf.c:8067 #5 0x00000040f176 in bpf_object__open_file /src/libbpf/src/libbpf.c:8090 #6 0x000000400c16 in main /poc/poc.c:8 #7 0x7fc3043d25b4 in __libc_start_call_main (/lib64/libc.so.6+0x35b4) #8 0x7fc3043d2667 in __libc_start_main@@GLIBC_2.34 (/lib64/libc.so.6+0x3667) #9 0x000000400b34 in _start (/poc/poc+0x400b34) 0x7c7302fe0000 is located 64 bytes before 104-byte region [0x7c7302fe0040,0x7c7302fe00a8) allocated by thread T0 here: #0 0x7fc3046e716b in malloc (/lib64/libasan.so.8+0xe716b) #1 0x7fc3045ee600 in __libelf_set_rawdata_wrlock (/lib64/libelf.so.1+0xb600) #2 0x7fc3045ef018 in __elf_getdata_rdlock (/lib64/libelf.so.1+0xc018) #3 0x00000040642f in elf_sec_data /src/libbpf/src/libbpf.c:3740 The problem here is that currently, libbpf only checks that the program end is within the section bounds. There used to be a check `while (sec_off < sec_sz)` in bpf_object__add_programs, however, it was removed by commit 6245947c1b3c ("libbpf: Allow gaps in BPF program sections to support overriden weak functions"). Add a check for detecting the overflow of `sec_off + prog_sz` to bpf_object__init_prog to fix this issue. [1] https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md Fixes: 6245947c1b3c ("libbpf: Allow gaps in BPF program sections to support overriden weak functions") Reported-by: lmarch2 <2524158037@qq.com> Signed-off-by: Viktor Malik <vmalik@redhat.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Reviewed-by: Shung-Hsi Yu <shung-hsi.yu@suse.com> Link: https://github.com/lmarch2/poc/blob/main/libbpf/libbpf.md Link: https://lore.kernel.org/bpf/20250415155014.397603-1-vmalik@redhat.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-05-29libbpf: Fix out-of-bound readNandakumar Edamana
[ Upstream commit 236d3910117e9f97ebf75e511d8bcc950f1a4e5f ] In `set_kcfg_value_str`, an untrusted string is accessed with the assumption that it will be at least two characters long due to the presence of checks for opening and closing quotes. But the check for the closing quote (value[len - 1] != '"') misses the fact that it could be checking the opening quote itself in case of an invalid input that consists of just the opening quote. This commit adds an explicit check to make sure the string is at least two characters long. Signed-off-by: Nandakumar Edamana <nandakumar@nandakumar.co.in> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20250221210110.3182084-1-nandakumar@nandakumar.co.in Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-20libbpf: Prevent compiler warnings/errorsEder Zulian
commit 7f4ec77f3fee41dd6a41f03a40703889e6e8f7b2 upstream. Initialize 'new_off' and 'pad_bits' to 0 and 'pad_type' to NULL in btf_dump_emit_bit_padding to prevent compiler warnings/errors which are observed when compiling with 'EXTRA_CFLAGS=-g -Og' options, but do not happen when compiling with current default options. For example, when compiling libbpf with $ make "EXTRA_CFLAGS=-g -Og" -C tools/lib/bpf/ clean all Clang version 17.0.6 and GCC 13.3.1 fail to compile btf_dump.c due to following errors: btf_dump.c: In function ‘btf_dump_emit_bit_padding’: btf_dump.c:903:42: error: ‘new_off’ may be used uninitialized [-Werror=maybe-uninitialized] 903 | if (new_off > cur_off && new_off <= next_off) { | ~~~~~~~~^~~~~~~~~~~ btf_dump.c:870:13: note: ‘new_off’ was declared here 870 | int new_off, pad_bits, bits, i; | ^~~~~~~ btf_dump.c:917:25: error: ‘pad_type’ may be used uninitialized [-Werror=maybe-uninitialized] 917 | btf_dump_printf(d, "\n%s%s: %d;", pfx(lvl), pad_type, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 918 | in_bitfield ? new_off - cur_off : 0); | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ btf_dump.c:871:21: note: ‘pad_type’ was declared here 871 | const char *pad_type; | ^~~~~~~~ btf_dump.c:930:20: error: ‘pad_bits’ may be used uninitialized [-Werror=maybe-uninitialized] 930 | if (bits == pad_bits) { | ^ btf_dump.c:870:22: note: ‘pad_bits’ was declared here 870 | int new_off, pad_bits, bits, i; | ^~~~~~~~ cc1: all warnings being treated as errors Signed-off-by: Eder Zulian <ezulian@redhat.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/bpf/20241022172329.3871958-3-ezulian@redhat.com Signed-off-by: He Zhe <zhe.he@windriver.com> Signed-off-by: Xiangyu Chen <xiangyu.chen@windriver.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-04-10libbpf: Fix hypothetical STT_SECTION extern NULL deref caseAndrii Nakryiko
[ Upstream commit e0525cd72b5979d8089fe524a071ea93fd011dc9 ] Fix theoretical NULL dereference in linker when resolving *extern* STT_SECTION symbol against not-yet-existing ELF section. Not sure if it's possible in practice for valid ELF object files (this would require embedded assembly manipulations, at which point BTF will be missing), but fix the s/dst_sym/dst_sec/ typo guarding this condition anyways. Fixes: faf6ed321cf6 ("libbpf: Add BPF static linker APIs") Fixes: a46349227cd8 ("libbpf: Add linker extern resolution support for functions and global variables") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20250220002821.834400-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-02-08libbpf: Fix incorrect traversal end type ID when marking BTF_IS_EMBEDDEDPu Lehui
[ Upstream commit 5ca681a86ef93369685cb63f71994f4cf7303e7c ] When redirecting the split BTF to the vmlinux base BTF, we need to mark the distilled base struct/union members of split BTF structs/unions in id_map with BTF_IS_EMBEDDED. This indicates that these types must match both name and size later. Therefore, we need to traverse the entire split BTF, which involves traversing type IDs from nr_dist_base_types to nr_types. However, the current implementation uses an incorrect traversal end type ID, so let's correct it. Fixes: 19e00c897d50 ("libbpf: Split BTF relocation") Signed-off-by: Pu Lehui <pulehui@huawei.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20250115100241.4171581-3-pulehui@huaweicloud.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-02-08libbpf: Fix return zero when elf_begin failedPu Lehui
[ Upstream commit 5436a54332c19df0acbef2b87cbf9f7cba56f2dd ] The error number of elf_begin is omitted when encapsulating the btf_find_elf_sections function. Fixes: c86f180ffc99 ("libbpf: Make btf_parse_elf process .BTF.base transparently") Signed-off-by: Pu Lehui <pulehui@huawei.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20250115100241.4171581-2-pulehui@huaweicloud.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-02-08libbpf: Fix segfault due to libelf functions not setting errnoQuentin Monnet
[ Upstream commit e10500b69c3f3378f3dcfc8c2fe4cdb74fc844f5 ] Libelf functions do not set errno on failure. Instead, it relies on its internal _elf_errno value, that can be retrieved via elf_errno (or the corresponding message via elf_errmsg()). From "man libelf": If a libelf function encounters an error it will set an internal error code that can be retrieved with elf_errno. Each thread maintains its own separate error code. The meaning of each error code can be determined with elf_errmsg, which returns a string describing the error. As a consequence, libbpf should not return -errno when a function from libelf fails, because an empty value will not be interpreted as an error and won't prevent the program to stop. This is visible in bpf_linker__add_file(), for example, where we call a succession of functions that rely on libelf: err = err ?: linker_load_obj_file(linker, filename, opts, &obj); err = err ?: linker_append_sec_data(linker, &obj); err = err ?: linker_append_elf_syms(linker, &obj); err = err ?: linker_append_elf_relos(linker, &obj); err = err ?: linker_append_btf(linker, &obj); err = err ?: linker_append_btf_ext(linker, &obj); If the object file that we try to process is not, in fact, a correct object file, linker_load_obj_file() may fail with errno not being set, and return 0. In this case we attempt to run linker_append_elf_sysms() and may segfault. This can happen (and was discovered) with bpftool: $ bpftool gen object output.o sample_ret0.bpf.c libbpf: failed to get ELF header for sample_ret0.bpf.c: invalid `Elf' handle zsh: segmentation fault (core dumped) bpftool gen object output.o sample_ret0.bpf.c Fix the issue by returning a non-null error code (-EINVAL) when libelf functions fail. Fixes: faf6ed321cf6 ("libbpf: Add BPF static linker APIs") Signed-off-by: Quentin Monnet <qmo@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20241205135942.65262-1-qmo@kernel.org Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-02-08libbpf: don't adjust USDT semaphore address if .stapsdt.base addr is missingAndrii Nakryiko
[ Upstream commit 98ebe5ef6f5c4517ba92fb3e56f95827ebea83fd ] USDT ELF note optionally can record an offset of .stapsdt.base, which is used to make adjustments to USDT target attach address. Currently, libbpf will do this address adjustment unconditionally if it finds .stapsdt.base ELF section in target binary. But there is a corner case where .stapsdt.base ELF section is present, but specific USDT note doesn't reference it. In such case, libbpf will basically just add base address and end up with absolutely incorrect USDT target address. This adjustment has to be done only if both .stapsdt.sema section is present and USDT note is recording a reference to it. Fixes: 74cc6311cec9 ("libbpf: Add USDT notes parsing and resolution logic") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/r/20241121224558.796110-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-05libbpf: move global data mmap()'ing into bpf_object__load()Andrii Nakryiko
[ Upstream commit 137978f422516a128326df55c0ba23605f925e21 ] Since BPF skeleton inception libbpf has been doing mmap()'ing of global data ARRAY maps in bpf_object__load_skeleton() API, which is used by code generated .skel.h files (i.e., by BPF skeletons only). This is wrong because if BPF object is loaded through generic bpf_object__load() API, global data maps won't be re-mmap()'ed after load step, and memory pointers returned from bpf_map__initial_value() would be wrong and won't reflect the actual memory shared between BPF program and user space. bpf_map__initial_value() return result is rarely used after load, so this went unnoticed for a really long time, until bpftrace project attempted to load BPF object through generic bpf_object__load() API and then used BPF subskeleton instantiated from such bpf_object. It turned out that .data/.rodata/.bss data updates through such subskeleton was "blackholed", all because libbpf wouldn't re-mmap() those maps during bpf_object__load() phase. Long story short, this step should be done by libbpf regardless of BPF skeleton usage, right after BPF map is created in the kernel. This patch moves this functionality into bpf_object__populate_internal_map() to achieve this. And bpf_object__load_skeleton() is now simple and almost trivial, only propagating these mmap()'ed pointers into user-supplied skeleton structs. We also do trivial adjustments to error reporting inside bpf_object__populate_internal_map() for consistency with the rest of libbpf's map-handling code. Reported-by: Alastair Robertson <ajor@meta.com> Reported-by: Jonathan Wiepert <jwiepert@meta.com> Fixes: d66562fba1ce ("libbpf: Add BPF object skeleton support") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20241023043908.3834423-3-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-05libbpf: never interpret subprogs in .text as entry programsAndrii Nakryiko
[ Upstream commit db089c9158c1d535a36dfc010e5db37fccea2561 ] Libbpf pre-1.0 had a legacy logic of allowing singular non-annotated (i.e., not having explicit SEC() annotation) function to be treated as sole entry BPF program (unless there were other explicit entry programs). This behavior was dropped during libbpf 1.0 transition period (unless LIBBPF_STRICT_SEC_NAME flag was unset in libbpf_mode). When 1.0 was released and all the legacy behavior was removed, the bug slipped through leaving this legacy behavior around. Fix this for good, as it actually causes very confusing behavior if BPF object file only has subprograms, but no entry programs. Fixes: bd054102a8c7 ("libbpf: enforce strict libbpf 1.0 behaviors") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20241010211731.4121837-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-05libbpf: fix sym_is_subprog() logic for weak global subprogsAndrii Nakryiko
[ Upstream commit 4073213488be542f563eb4b2457ab4cbcfc2b738 ] sym_is_subprog() is incorrectly rejecting relocations against *weak* global subprogs. Fix that by realizing that STB_WEAK is also a global function. While it seems like verifier doesn't support taking an address of non-static subprog right now, it's still best to fix support for it on libbpf side, otherwise users will get a very confusing error during BPF skeleton generation or static linking due to misinterpreted relocation: libbpf: prog 'handle_tp': bad map relo against 'foo' in section '.text' Error: failed to open BPF object file: Relocation failed It's clearly not a map relocation, but is treated and reported as such without this fix. Fixes: 53eddb5e04ac ("libbpf: Support subprog address relocation") Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20241009011554.880168-1-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-05libbpf: Add missing per-arch include pathBjörn Töpel
[ Upstream commit 710fbca820c721cdd60fa8c5bbe9deb4c0788aae ] libbpf does not include the per-arch tools include path, e.g. tools/arch/riscv/include. Some architectures depend those files to build properly. Include tools/arch/$(SUBARCH)/include in the libbpf build. Fixes: 6d74d178fe6e ("tools: Add riscv barrier implementation") Signed-off-by: Björn Töpel <bjorn@rivosinc.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240927131355.350918-1-bjorn@kernel.org Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-05libbpf: Fix output .symtab byte-order during linkingTony Ambardar
[ Upstream commit f896b4a5399e97af0b451fcf04754ed316935674 ] Object linking output data uses the default ELF_T_BYTE type for '.symtab' section data, which disables any libelf-based translation. Explicitly set the ELF_T_SYM type for output to restore libelf's byte-order conversion, noting that input '.symtab' data is already correctly translated. Fixes: faf6ed321cf6 ("libbpf: Add BPF static linker APIs") Signed-off-by: Tony Ambardar <tony.ambardar@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/87868bfeccf3f51aec61260073f8778e9077050a.1726475448.git.tony.ambardar@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-05libbpf: Fix expected_attach_type set handling in program load callbackTao Chen
[ Upstream commit a400d08b3014a4f4e939366bb6fd769b9caff4c9 ] Referenced commit broke the logic of resetting expected_attach_type to zero for allowed program types if kernel doesn't yet support such field. We do need to overwrite and preserve expected_attach_type for multi-uprobe though, but that can be done explicitly in libbpf_prepare_prog_load(). Fixes: 5902da6d8a52 ("libbpf: Add uprobe multi link support to bpf_program__attach_usdt") Suggested-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Tao Chen <chen.dylane@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240925153012.212866-1-chen.dylane@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-09-22Merge tag 'perf-tools-for-v6.12-1-2024-09-19' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools Pull perf tools updates from Arnaldo Carvalho de Melo: - Use BPF + BTF to collect and pretty print syscall and tracepoint arguments in 'perf trace', done as an GSoC activity - Data-type profiling improvements: - Cache debuginfo to speed up data type resolution - Add the 'typecln' sort order, to show which cacheline in a target is hot or cold. The following shows members in the cfs_rq's first cache line: $ perf report -s type,typecln,typeoff -H ... - 2.67% struct cfs_rq + 1.23% struct cfs_rq: cache-line 2 + 0.57% struct cfs_rq: cache-line 4 + 0.46% struct cfs_rq: cache-line 6 - 0.41% struct cfs_rq: cache-line 0 0.39% struct cfs_rq +0x14 (h_nr_running) 0.02% struct cfs_rq +0x38 (tasks_timeline.rb_leftmost) - When a typedef resolves to a unnamed struct, use the typedef name - When a struct has just one basic type field (int, etc), resolve the type sort order to the name of the struct, not the type of the field - Support type folding/unfolding in the data-type annotation TUI - Fix bitfields offsets and sizes - Initial support for PowerPC, using libcapstone and the usual objdump disassembly parsing routines - Add support for disassembling and addr2line using the LLVM libraries, speeding up those operations - Support --addr2line option in 'perf script' as with other tools - Intel branch counters (LBR event logging) support, only available in recent Intel processors, for instance, the new "brcntr" field can be asked from 'perf script' to print the information collected from this feature: $ perf script -F +brstackinsn,+brcntr # Branch counter abbr list: # branch-instructions:ppp = A # branch-misses = B # '-' No event occurs # '+' Event occurrences may be lost due to branch counter saturated tchain_edit 332203 3366329.405674: 53030 branch-instructions:ppp: 401781 f3+0x2c (home/sdp/test/tchain_edit) f3+31: 0000000000401774 insn: eb 04 br_cntr: AA # PRED 5 cycles [5] 000000000040177a insn: 81 7d fc 0f 27 00 00 0000000000401781 insn: 7e e3 br_cntr: A # PRED 1 cycles [6] 2.00 IPC 0000000000401766 insn: 8b 45 fc 0000000000401769 insn: 83 e0 01 000000000040176c insn: 85 c0 000000000040176e insn: 74 06 br_cntr: A # PRED 1 cycles [7] 4.00 IPC 0000000000401776 insn: 83 45 fc 01 000000000040177a insn: 81 7d fc 0f 27 00 00 0000000000401781 insn: 7e e3 br_cntr: A # PRED 7 cycles [14] 0.43 IPC - Support Timed PEBS (Precise Event-Based Sampling), a recent hardware feature in Intel processors - Add 'perf ftrace profile' subcommand, using ftrace's function-graph tracer so that users can see the total, average, max execution time as well as the number of invocations easily, for instance: $ sudo perf ftrace profile -G __x64_sys_perf_event_open -- \ perf stat -e cycles -C1 true 2> /dev/null | head # Total (us) Avg (us) Max (us) Count Function 65.611 65.611 65.611 1 __x64_sys_perf_event_open 30.527 30.527 30.527 1 anon_inode_getfile 30.260 30.260 30.260 1 __anon_inode_getfile 29.700 29.700 29.700 1 alloc_file_pseudo 17.578 17.578 17.578 1 d_alloc_pseudo 17.382 17.382 17.382 1 __d_alloc 16.738 16.738 16.738 1 kmem_cache_alloc_lru 15.686 15.686 15.686 1 perf_event_alloc 14.012 7.006 11.264 2 obj_cgroup_charge - 'perf sched timehist' improvements, including the addition of priority showing/filtering command line options - Varios improvements to the 'perf probe', including 'perf test' regression testings - Introduce the 'perf check', initially to check if some feature is in place, using it in 'perf test' - Various fixes for 32-bit systems - Address more leak sanitizer failures - Fix memory leaks (LBR, disasm lock ops, etc) - More reference counting fixes (branch_info, etc) - Constify 'struct perf_tool' parameters to improve code generation and reduce the chances of having its internals changed, which isn't expected - More constifications in various other places - Add more build tests, including for JEVENTS - Add more 'perf test' entries ('perf record LBR', pipe/inject, --setup-filter, 'perf ftrace', 'cgroup sampling', etc) - Inject build ids for all entries in a call chain in 'perf inject', not just for the main sample - Improve the BPF based sample filter, allowing root to setup filters in bpffs that then can be used by non-root users - Allow filtering by cgroups with the BPF based sample filter - Allow a more compact way for 'perf mem report' using the -T/--type-profile and also provide a --sort option similar to the one in 'perf report', 'perf top', to setup the sort order manually - Fix --group behavior in 'perf annotate' when leader has no samples, where it was not showing anything even when other events in the group had samples - Fix spinlock and rwlock accounting in 'perf lock contention' - Fix libsubcmd fixdep Makefile dependencies - Improve 'perf ftrace' error message when ftrace isn't available - Update various Intel JSON vendor event files - ARM64 CoreSight hardware tracing infrastructure improvements, mostly not visible to users - Update power10 JSON events * tag 'perf-tools-for-v6.12-1-2024-09-19' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools: (310 commits) perf trace: Mark the 'head' arg in the set_robust_list syscall as coming from user space perf trace: Mark the 'rseq' arg in the rseq syscall as coming from user space perf env: Find correct branch counter info on hybrid perf evlist: Print hint for group tools: Drop nonsensical -O6 perf pmu: To info add event_type_desc perf evsel: Add accessor for tool_event perf pmus: Fake PMU clean up perf list: Avoid potential out of bounds memory read perf help: Fix a typo ("bellow") perf ftrace: Detect whether ftrace is enabled on system perf test shell probe_vfs_getname: Remove extraneous '=' from probe line number regex perf build: Require at least clang 16.0.6 to build BPF skeletons perf trace: If a syscall arg is marked as 'const', assume it is coming _from_ userspace perf parse-events: Remove duplicated include in parse-events.c perf callchain: Allow symbols to be optional when resolving a callchain perf inject: Lazy build-id mmap2 event insertion perf inject: Add new mmap2-buildid-all option perf inject: Fix build ID injection perf annotate-data: Add pr_debug_scope() ...
2024-09-12libbpf: Add bpf_object__token_fd accessorIhor Solodrai
Add a LIBBPF_API function to retrieve the token_fd from a bpf_object. Without this accessor, if user needs a token FD they have to get it manually via bpf_token_create, even though a token might have been already created by bpf_object__load. Suggested-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Ihor Solodrai <ihor.solodrai@pm.me> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240913001858.3345583-1-ihor.solodrai@pm.me
2024-09-10libbpf: Fix uretprobe.multi.s programs auto attachmentJiri Olsa
As reported by Andrii we don't currently recognize uretprobe.multi.s programs as return probes due to using (wrong) strcmp function. Using str_has_pfx() instead to match uretprobe.multi prefix. Tests are passing, because the return program was executed as entry program and all counts were incremented properly. Reported-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240910125336.3056271-1-jolsa@kernel.org
2024-09-09libbpf: Fix some typos in commentsYusheng Zheng
Fix some spelling errors in the code comments of libbpf: betwen -> between paremeters -> parameters knowning -> knowing definiton -> definition compatiblity -> compatibility overriden -> overridden occured -> occurred proccess -> process managment -> management nessary -> necessary Signed-off-by: Yusheng Zheng <yunwei356@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240909225952.30324-1-yunwei356@gmail.com
2024-09-09libbpf: Fixed getting wrong return address on arm64 architectureShuyi Cheng
ARM64 has a separate lr register to store the return address, so here you only need to read the lr register to get the return address, no need to dereference it again. Signed-off-by: Shuyi Cheng <chengshuyi@linux.alibaba.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/1725787433-77262-1-git-send-email-chengshuyi@linux.alibaba.com
2024-09-06libbpf: Workaround (another) -Wmaybe-uninitialized false positiveSam James
We get this with GCC 15 -O3 (at least): ``` libbpf.c: In function ‘bpf_map__init_kern_struct_ops’: libbpf.c:1109:18: error: ‘mod_btf’ may be used uninitialized [-Werror=maybe-uninitialized] 1109 | kern_btf = mod_btf ? mod_btf->btf : obj->btf_vmlinux; | ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ libbpf.c:1094:28: note: ‘mod_btf’ was declared here 1094 | struct module_btf *mod_btf; | ^~~~~~~ In function ‘find_struct_ops_kern_types’, inlined from ‘bpf_map__init_kern_struct_ops’ at libbpf.c:1102:8: libbpf.c:982:21: error: ‘btf’ may be used uninitialized [-Werror=maybe-uninitialized] 982 | kern_type = btf__type_by_id(btf, kern_type_id); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ libbpf.c: In function ‘bpf_map__init_kern_struct_ops’: libbpf.c:967:21: note: ‘btf’ was declared here 967 | struct btf *btf; | ^~~ ``` This is similar to the other libbpf fix from a few weeks ago for the same modelling-errno issue (fab45b962749184e1a1a57c7c583782b78fad539). Signed-off-by: Sam James <sam@gentoo.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://bugs.gentoo.org/939106 Link: https://lore.kernel.org/bpf/f6962729197ae7cdf4f6d1512625bd92f2322d31.1725630494.git.sam@gentoo.org
2024-09-05libbpf: fix some typos in libbpfLin Yikai
Hi, fix some spelling errors in libbpf, the details are as follows: -in the code comments: termintaing->terminating architecutre->architecture requring->requiring recored->recoded sanitise->sanities allowd->allowed abover->above see bpf_udst_arg()->see bpf_usdt_arg() Signed-off-by: Lin Yikai <yikai.lin@vivo.com> Link: https://lore.kernel.org/r/20240905110354.3274546-3-yikai.lin@vivo.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-09-04libbpf: Fix accessing first syscall argument on RV64Pu Lehui
On RV64, as Ilya mentioned before [0], the first syscall parameter should be accessed through orig_a0 (see arch/riscv64/include/asm/syscall.h), otherwise it will cause selftests like bpf_syscall_macro, vmlinux, test_lsm, etc. to fail on RV64. Let's fix it by using the struct pt_regs style CO-RE direct access. Signed-off-by: Pu Lehui <pulehui@huawei.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220209021745.2215452-1-iii@linux.ibm.com [0] Link: https://lore.kernel.org/bpf/20240831041934.1629216-5-pulehui@huaweicloud.com
2024-09-04libbpf: Access first syscall argument with CO-RE direct read on arm64Pu Lehui
Currently PT_REGS_PARM1 SYSCALL(x) is consistent with PT_REGS_PARM1_CORE SYSCALL(x), which will introduce the overhead of BPF_CORE_READ(), taking into account the read pt_regs comes directly from the context, let's use CO-RE direct read to access the first system call argument. Suggested-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Pu Lehui <pulehui@huawei.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Xu Kuohai <xukuohai@huawei.com> Link: https://lore.kernel.org/bpf/20240831041934.1629216-3-pulehui@huaweicloud.com
2024-09-04libbpf: Access first syscall argument with CO-RE direct read on s390Pu Lehui
Currently PT_REGS_PARM1 SYSCALL(x) is consistent with PT_REGS_PARM1_CORE SYSCALL(x), which will introduce the overhead of BPF_CORE_READ(), taking into account the read pt_regs comes directly from the context, let's use CO-RE direct read to access the first system call argument. Suggested-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Pu Lehui <pulehui@huawei.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240831041934.1629216-2-pulehui@huaweicloud.com
2024-08-30libbpf: Ensure new BTF objects inherit input endiannessTony Ambardar
New split BTF needs to preserve base's endianness. Similarly, when creating a distilled BTF, we need to preserve original endianness. Fix by updating libbpf's btf__distill_base() and btf_new_empty() to retain the byte order of any source BTF objects when creating new ones. Fixes: ba451366bf44 ("libbpf: Implement basic split BTF support") Fixes: 58e185a0dc35 ("libbpf: Add btf__distill_base() creating split BTF with distilled base BTF") Reported-by: Song Liu <song@kernel.org> Reported-by: Eduard Zingerman <eddyz87@gmail.com> Suggested-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Tony Ambardar <tony.ambardar@gmail.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Tested-by: Alan Maguire <alan.maguire@oracle.com> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/bpf/6358db36c5f68b07873a0a5be2d062b1af5ea5f8.camel@gmail.com/ Link: https://lore.kernel.org/bpf/20240830095150.278881-1-tony.ambardar@gmail.com
2024-08-29libbpf: Fix bpf_object__open_skeleton()'s mishandling of optionsAndrii Nakryiko
We do an ugly copying of options in bpf_object__open_skeleton() just to be able to set object name from skeleton's recorded name (while still allowing user to override it through opts->object_name). This is not just ugly, but it also is broken due to memcpy() that doesn't take into account potential skel_opts' and user-provided opts' sizes differences due to backward and forward compatibility. This leads to copying over extra bytes and then failing to validate options properly. It could, technically, lead also to SIGSEGV, if we are unlucky. So just get rid of that memory copy completely and instead pass default object name into bpf_object_open() directly, simplifying all this significantly. The rule now is that obj_name should be non-NULL for bpf_object_open() when called with in-memory buffer, so validate that explicitly as well. We adopt bpf_object__open_mem() to this as well and generate default name (based on buffer memory address and size) outside of bpf_object_open(). Fixes: d66562fba1ce ("libbpf: Add BPF object skeleton support") Reported-by: Daniel Müller <deso@posteo.net> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Daniel Müller <deso@posteo.net> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/bpf/20240827203721.1145494-1-andrii@kernel.org
2024-08-15libbpf: Workaround -Wmaybe-uninitialized false positiveSam James
In `elf_close`, we get this with GCC 15 -O3 (at least): ``` In function ‘elf_close’, inlined from ‘elf_close’ at elf.c:53:6, inlined from ‘elf_find_func_offset_from_file’ at elf.c:384:2: elf.c:57:9: warning: ‘elf_fd.elf’ may be used uninitialized [-Wmaybe-uninitialized] 57 | elf_end(elf_fd->elf); | ^~~~~~~~~~~~~~~~~~~~ elf.c: In function ‘elf_find_func_offset_from_file’: elf.c:377:23: note: ‘elf_fd.elf’ was declared here 377 | struct elf_fd elf_fd; | ^~~~~~ In function ‘elf_close’, inlined from ‘elf_close’ at elf.c:53:6, inlined from ‘elf_find_func_offset_from_file’ at elf.c:384:2: elf.c:58:9: warning: ‘elf_fd.fd’ may be used uninitialized [-Wmaybe-uninitialized] 58 | close(elf_fd->fd); | ^~~~~~~~~~~~~~~~~ elf.c: In function ‘elf_find_func_offset_from_file’: elf.c:377:23: note: ‘elf_fd.fd’ was declared here 377 | struct elf_fd elf_fd; | ^~~~~~ ``` In reality, our use is fine, it's just that GCC doesn't model errno here (see linked GCC bug). Suppress -Wmaybe-uninitialized accordingly by initializing elf_fd.fd to -1 and elf_fd.elf to NULL. I've done this in two other functions as well given it could easily occur there too (same access/use pattern). Signed-off-by: Sam James <sam@gentoo.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://gcc.gnu.org/PR114952 Link: https://lore.kernel.org/bpf/14ec488a1cac02794c2fa2b83ae0cef1bce2cb36.1723578546.git.sam@gentoo.org
2024-08-12libbpf: Fix license for btf_relocate.cAlan Maguire
License should be // SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) ...as with other libbpf files. Fixes: 19e00c897d50 ("libbpf: Split BTF relocation") Reported-by: Neill Kapron <nkapron@google.com> Signed-off-by: Alan Maguire <alan.maguire@oracle.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Yonghong Song <yonghong.song@linux.dev> Link: https://lore.kernel.org/bpf/20240810093504.2111134-1-alan.maguire@oracle.com
2024-08-05tools build: Correct bpf fixdep dependenciesBrian Norris
The dependencies in tools/lib/bpf/Makefile are incorrect. Before we recurse to build $(BPF_IN_STATIC), we need to build its 'fixdep' executable. I can't use the usual shortcut from Makefile.include: <target>: <sources> fixdep because its 'fixdep' target relies on $(OUTPUT), and $(OUTPUT) differs in the parent 'make' versus the child 'make' -- so I imitate it via open-coding. I tweak a few $(MAKE) invocations while I'm at it, because 1. I'm adding a new recursive make; and 2. these recursive 'make's print spurious lines about files that are "up to date" (which isn't normally a feature in Kbuild subtargets) or "jobserver not available" (see [1]) I also need to tweak the assignment of the OUTPUT variable, so that relative path builds work. For example, for 'make tools/lib/bpf', OUTPUT is unset, and is usually treated as "cwd" -- but recursive make will change cwd and so OUTPUT has a new meaning. For consistency, I ensure OUTPUT is always an absolute path. And $(Q) gets a backup definition in tools/build/Makefile.include, because Makefile.include is sometimes included without tools/build/Makefile, so the "quiet command" stuff doesn't actually work consistently without it. After this change, top-level builds result in an empty grep result from: $ grep 'cannot find fixdep' $(find tools/ -name '*.cmd') [1] https://www.gnu.org/software/make/manual/html_node/MAKE-Variable.html If we're not using $(MAKE) directly, then we need to use more '+'. Signed-off-by: Brian Norris <briannorris@chromium.org> Acked-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Ian Rogers <irogers@google.com> Cc: Josh Poimboeuf <jpoimboe@kernel.org> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Richter <tmricht@linux.ibm.com> Link: https://lore.kernel.org/r/20240715203325.3832977-4-briannorris@chromium.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2024-07-29libbpf: Don't take direct pointers into BTF data from st_opsDavid Vernet
In struct bpf_struct_ops, we have take a pointer to a BTF type name, and a struct btf_type. This was presumably done for convenience, but can actually result in subtle and confusing bugs given that BTF data can be invalidated before a program is loaded. For example, in sched_ext, we may sometimes resize a data section after a skeleton has been opened, but before the struct_ops scheduler map has been loaded. This may cause the BTF data to be realloc'd, which can then cause a UAF when loading the program because the struct_ops map has pointers directly into the BTF data. We're already storing the BTF type_id in struct bpf_struct_ops. Because type_id is stable, we can therefore just update the places where we were looking at those pointers to instead do the lookups we need from the type_id. Fixes: 590a00888250 ("bpf: libbpf: Add STRUCT_OPS support") Signed-off-by: David Vernet <void@manifault.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240724171459.281234-1-void@manifault.com
2024-07-17libbpf: Fix no-args func prototype BTF dumping syntaxAndrii Nakryiko
For all these years libbpf's BTF dumper has been emitting not strictly valid syntax for function prototypes that have no input arguments. Instead of `int (*blah)()` we should emit `int (*blah)(void)`. This is not normally a problem, but it manifests when we get kfuncs in vmlinux.h that have no input arguments. Due to compiler internal specifics, we get no BTF information for such kfuncs, if they are not declared with proper `(void)`. The fix is trivial. We also need to adjust a few ancient tests that happily assumed `()` is correct. Fixes: 351131b51c7a ("libbpf: add btf_dump API for BTF-to-C conversion") Reported-by: Tejun Heo <tj@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Stanislav Fomichev <sdf@fomichev.me> Link: https://lore.kernel.org/bpf/20240712224442.282823-1-andrii@kernel.org
2024-07-09libbpf: improve old BPF skeleton handling for map auto-attachAndrii Nakryiko
Improve how we handle old BPF skeletons when it comes to BPF map auto-attachment. Emit one warn-level message per each struct_ops map that could have been auto-attached, if user provided recent enough BPF skeleton version. Don't spam log if there are no relevant struct_ops maps, though. This should help users realize that they probably need to regenerate BPF skeleton header with more recent bpftool/libbpf-cargo (or whatever other means of BPF skeleton generation). Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/r/20240708204540.4188946-4-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-07-09libbpf: fix BPF skeleton forward/backward compat handlingAndrii Nakryiko
BPF skeleton was designed from day one to be extensible. Generated BPF skeleton code specifies actual sizes of map/prog/variable skeletons for that reason and libbpf is supposed to work with newer/older versions correctly. Unfortunately, it was missed that we implicitly embed hard-coded most up-to-date (according to libbpf's version of libbpf.h header used to compile BPF skeleton header) sizes of those structs, which can differ from the actual sizes at runtime when libbpf is used as a shared library. We have a few places were we just index array of maps/progs/vars, which implicitly uses these potentially invalid sizes of structs. This patch aims to fix this problem going forward. Once this lands, we'll backport these changes in Github repo to create patched releases for older libbpfs. Acked-by: Eduard Zingerman <eddyz87@gmail.com> Reviewed-by: Alan Maguire <alan.maguire@oracle.com> Fixes: d66562fba1ce ("libbpf: Add BPF object skeleton support") Fixes: 430025e5dca5 ("libbpf: Add subskeleton scaffolding") Fixes: 08ac454e258e ("libbpf: Auto-attach struct_ops BPF maps in BPF skeleton") Co-developed-by: Mykyta Yatsenko <yatsenko@meta.com> Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/r/20240708204540.4188946-3-andrii@kernel.org Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-07-08libbpf: Add NULL checks to bpf_object__{prev_map,next_map}Andreas Ziegler
In the current state, an erroneous call to bpf_object__find_map_by_name(NULL, ...) leads to a segmentation fault through the following call chain: bpf_object__find_map_by_name(obj = NULL, ...) -> bpf_object__for_each_map(pos, obj = NULL) -> bpf_object__next_map((obj = NULL), NULL) -> return (obj = NULL)->maps While calling bpf_object__find_map_by_name with obj = NULL is obviously incorrect, this should not lead to a segmentation fault but rather be handled gracefully. As __bpf_map__iter already handles this situation correctly, we can delegate the check for the regular case there and only add a check in case the prev or next parameter is NULL. Signed-off-by: Andreas Ziegler <ziegler.andreas@siemens.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20240703083436.505124-1-ziegler.andreas@siemens.com
2024-07-01libbpf: Fix error handling in btf__distill_base()Alan Maguire
Coverity points out that after calling btf__new_empty_split() the wrong value is checked for error. Fixes: 58e185a0dc35 ("libbpf: Add btf__distill_base() creating split BTF with distilled base BTF") Reported-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alan Maguire <alan.maguire@oracle.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20240629100058.2866763-1-alan.maguire@oracle.com
2024-06-26libbpf: Fix clang compilation error in btf_relocate.cAlan Maguire
When building with clang for ARCH=i386, the following errors are observed: CC kernel/bpf/btf_relocate.o ./tools/lib/bpf/btf_relocate.c:206:23: error: implicit truncation from 'int' to a one-bit wide bit-field changes value from 1 to -1 [-Werror,-Wsingle-bit-bitfield-constant-conversion] 206 | info[id].needs_size = true; | ^ ~ ./tools/lib/bpf/btf_relocate.c:256:25: error: implicit truncation from 'int' to a one-bit wide bit-field changes value from 1 to -1 [-Werror,-Wsingle-bit-bitfield-constant-conversion] 256 | base_info.needs_size = true; | ^ ~ 2 errors generated. The problem is we use 1-bit, 31-bit bitfields in a signed int. Changing to bool needs_size: 1; unsigned int size:31; ...resolves the error and pahole reports that 4 bytes are used for the underlying representation: $ pahole btf_name_info tools/lib/bpf/btf_relocate.o struct btf_name_info { const char * name; /* 0 8 */ unsigned int needs_size:1; /* 8: 0 4 */ unsigned int size:31; /* 8: 1 4 */ __u32 id; /* 12 4 */ /* size: 16, cachelines: 1, members: 4 */ /* last cacheline: 16 bytes */ }; Signed-off-by: Alan Maguire <alan.maguire@oracle.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240624192903.854261-1-alan.maguire@oracle.com
2024-06-24libbpf: Skip base btf sanity checksAntoine Tenart
When upgrading to libbpf 1.3 we noticed a big performance hit while loading programs using CORE on non base-BTF symbols. This was tracked down to the new BTF sanity check logic. The issue is the base BTF definitions are checked first for the base BTF and then again for every module BTF. Loading 5 dummy programs (using libbpf-rs) that are using CORE on a non-base BTF symbol on my system: - Before this fix: 3s. - With this fix: 0.1s. Fix this by only checking the types starting at the BTF start id. This should ensure the base BTF is still checked as expected but only once (btf->start_id == 1 when creating the base BTF), and then only additional types are checked for each module BTF. Fixes: 3903802bb99a ("libbpf: Add basic BTF sanity validation") Signed-off-by: Antoine Tenart <atenart@kernel.org> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Reviewed-by: Alan Maguire <alan.maguire@oracle.com> Link: https://lore.kernel.org/bpf/20240624090908.171231-1-atenart@kernel.org
2024-06-21libbpf,bpf: Share BTF relocate-related code with kernelAlan Maguire
Share relocation implementation with the kernel. As part of this, we also need the type/string iteration functions so also share btf_iter.c file. Relocation code in kernel and userspace is identical save for the impementation of the reparenting of split BTF to the relocated base BTF and retrieval of the BTF header from "struct btf"; these small functions need separate user-space and kernel implementations for the separate "struct btf"s they operate upon. One other wrinkle on the kernel side is we have to map .BTF.ids in modules as they were generated with the type ids used at BTF encoding time. btf_relocate() optionally returns an array mapping from old BTF ids to relocated ids, so we use that to fix up these references where needed for kfuncs. Signed-off-by: Alan Maguire <alan.maguire@oracle.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/bpf/20240620091733.1967885-5-alan.maguire@oracle.com
2024-06-21libbpf: Split field iter code into its own file kernelAlan Maguire
This will allow it to be shared with the kernel. No functional change. Suggested-by: Andrii Nakryiko <andrii@kernel.org> Signed-off-by: Alan Maguire <alan.maguire@oracle.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240620091733.1967885-4-alan.maguire@oracle.com
2024-06-21libbpf: BTF relocation followup fixing naming, loop logicAlan Maguire
Use less verbose names in BTF relocation code and fix off-by-one error and typo in btf_relocate.c. Simplify loop over matching distilled types, moving from assigning a _next value in loop body to moving match check conditions into the guard. Suggested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com> Signed-off-by: Alan Maguire <alan.maguire@oracle.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/bpf/20240620091733.1967885-2-alan.maguire@oracle.com
2024-06-21libbpf: Checking the btf_type kind when fixing variable offsetsDonglin Peng
I encountered an issue when building the test_progs from the repository [1]: $ pwd /work/Qemu/x86_64/linux-6.10-rc2/tools/testing/selftests/bpf/ $ make test_progs V=1 [...] ./tools/sbin/bpftool gen object ./ip_check_defrag.bpf.linked2.o ./ip_check_defrag.bpf.linked1.o libbpf: failed to find symbol for variable 'bpf_dynptr_slice' in section '.ksyms' Error: failed to link './ip_check_defrag.bpf.linked1.o': No such file or directory (2) [...] Upon investigation, I discovered that the btf_types referenced in the '.ksyms' section had a kind of BTF_KIND_FUNC instead of BTF_KIND_VAR: $ bpftool btf dump file ./ip_check_defrag.bpf.linked1.o [...] [2] DATASEC '.ksyms' size=0 vlen=2 type_id=16 offset=0 size=0 (FUNC 'bpf_dynptr_from_skb') type_id=17 offset=0 size=0 (FUNC 'bpf_dynptr_slice') [...] [16] FUNC 'bpf_dynptr_from_skb' type_id=82 linkage=extern [17] FUNC 'bpf_dynptr_slice' type_id=85 linkage=extern [...] For a detailed analysis, please refer to [2]. We can add a kind checking to fix the issue. [1] https://github.com/eddyz87/bpf/tree/binsort-btf-dedup [2] https://lore.kernel.org/all/0c0ef20c-c05e-4db9-bad7-2cbc0d6dfae7@oracle.com/ Fixes: 8fd27bf69b86 ("libbpf: Add BPF static linker BTF and BTF.ext support") Signed-off-by: Donglin Peng <dolinux.peng@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Alan Maguire <alan.maguire@oracle.com> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/bpf/20240619122355.426405-1-dolinux.peng@gmail.com
2024-06-17libbpf: Make btf_parse_elf process .BTF.base transparentlyEduard Zingerman
Update btf_parse_elf() to check if .BTF.base section is present. The logic is as follows: if .BTF.base section exists: distilled_base := btf_new(.BTF.base) if distilled_base: btf := btf_new(.BTF, .base_btf=distilled_base) if base_btf: btf_relocate(btf, base_btf) else: btf := btf_new(.BTF) return btf In other words: - if .BTF.base section exists, load BTF from it and use it as a base for .BTF load; - if base_btf is specified and .BTF.base section exist, relocate newly loaded .BTF against base_btf. Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Signed-off-by: Alan Maguire <alan.maguire@oracle.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20240613095014.357981-6-alan.maguire@oracle.com
2024-06-17libbpf: Split BTF relocationAlan Maguire
Map distilled base BTF type ids referenced in split BTF and their references to the base BTF passed in, and if the mapping succeeds, reparent the split BTF to the base BTF. Relocation is done by first verifying that distilled base BTF only consists of named INT, FLOAT, ENUM, FWD, STRUCT and UNION kinds; then we sort these to speed lookups. Once sorted, the base BTF is iterated, and for each relevant kind we check for an equivalent in distilled base BTF. When found, the mapping from distilled -> base BTF id and string offset is recorded. In establishing mappings, we need to ensure we check STRUCT/UNION size when the STRUCT/UNION is embedded in a split BTF STRUCT/UNION, and when duplicate names exist for the same STRUCT/UNION. Otherwise size is ignored in matching STRUCT/UNIONs. Once all mappings are established, we can update type ids and string offsets in split BTF and reparent it to the new base. Signed-off-by: Alan Maguire <alan.maguire@oracle.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/bpf/20240613095014.357981-4-alan.maguire@oracle.com
2024-06-17libbpf: Add btf__distill_base() creating split BTF with distilled base BTFAlan Maguire
To support more robust split BTF, adding supplemental context for the base BTF type ids that split BTF refers to is required. Without such references, a simple shuffling of base BTF type ids (without any other significant change) invalidates the split BTF. Here the attempt is made to store additional context to make split BTF more robust. This context comes in the form of distilled base BTF providing minimal information (name and - in some cases - size) for base INTs, FLOATs, STRUCTs, UNIONs, ENUMs and ENUM64s along with modified split BTF that points at that base and contains any additional types needed (such as TYPEDEF, PTR and anonymous STRUCT/UNION declarations). This information constitutes the minimal BTF representation needed to disambiguate or remove split BTF references to base BTF. The rules are as follows: - INT, FLOAT, FWD are recorded in full. - if a named base BTF STRUCT or UNION is referred to from split BTF, it will be encoded as a zero-member sized STRUCT/UNION (preserving size for later relocation checks). Only base BTF STRUCT/UNIONs that are either embedded in split BTF STRUCT/UNIONs or that have multiple STRUCT/UNION instances of the same name will _need_ size checks at relocation time, but as it is possible a different set of types will be duplicates in the later to-be-resolved base BTF, we preserve size information for all named STRUCT/UNIONs. - if an ENUM[64] is named, a ENUM forward representation (an ENUM with no values) of the same size is used. - in all other cases, the type is added to the new split BTF. Avoiding struct/union/enum/enum64 expansion is important to keep the distilled base BTF representation to a minimum size. When successful, new representations of the distilled base BTF and new split BTF that refers to it are returned. Both need to be freed by the caller. So to take a simple example, with split BTF with a type referring to "struct sk_buff", we will generate distilled base BTF with a 0-member STRUCT sk_buff of the appropriate size, and the split BTF will refer to it instead. Tools like pahole can utilize such split BTF to populate the .BTF section (split BTF) and an additional .BTF.base section. Then when the split BTF is loaded, the distilled base BTF can be used to relocate split BTF to reference the current (and possibly changed) base BTF. So for example if "struct sk_buff" was id 502 when the split BTF was originally generated, we can use the distilled base BTF to see that id 502 refers to a "struct sk_buff" and replace instances of id 502 with the current (relocated) base BTF sk_buff type id. Distilled base BTF is small; when building a kernel with all modules using distilled base BTF as a test, overall module size grew by only 5.3Mb total across ~2700 modules. Signed-off-by: Alan Maguire <alan.maguire@oracle.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/bpf/20240613095014.357981-2-alan.maguire@oracle.com
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