- Sep 13, 2024
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Ihor Solodrai authored
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:
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- Sep 11, 2024
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Sam James authored
-O6 is very much not-a-thing. Really, this should've been dropped entirely in 49b3cd30 ("tools: Set the maximum optimization level according to the compiler being used") instead of just passing it for not-Clang. Just collapse it down to -O3, instead of "-O6 unless Clang, in which case -O3". GCC interprets > -O3 as -O3. It doesn't even interpret > -O3 as -Ofast, which is a good thing, given -Ofast has specific (non-)requirements for code built using it. So, this does nothing except look a bit daft. Remove the silliness and also save a few lines in the Makefiles accordingly. Reviewed-by:
Ian Rogers <irogers@google.com> Reviewed-by:
Jesper Juhl <jesperjuhl76@gmail.com> Signed-off-by:
Sam James <sam@gentoo.org> Acked-by:
Namhyung Kim <namhyung@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Bill Wendling <morbo@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Justin Stitt <justinstitt@google.com> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: llvm@lists.linux.dev Link: https://lore.kernel.org/r/4f01524fa4ea91c7146a41e26ceaf9dae4c127e4.1725821201.git.sam@gentoo.org Signed-off-by:
Arnaldo Carvalho de Melo <acme@redhat.com>
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- Sep 10, 2024
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Jiri Olsa authored
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:
Jiri Olsa <jolsa@kernel.org> Signed-off-by:
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- Sep 09, 2024
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Yusheng Zheng authored
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:
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Shuyi Cheng authored
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:
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- Sep 06, 2024
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Sam James authored
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 (fab45b96). Signed-off-by:
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- Sep 05, 2024
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Lin Yikai authored
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>
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Pu Lehui authored
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:
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Pu Lehui authored
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:
Xu Kuohai <xukuohai@huawei.com> Link: https://lore.kernel.org/bpf/20240831041934.1629216-3-pulehui@huaweicloud.com
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Pu Lehui authored
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:
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- Sep 04, 2024
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Aditya Gupta authored
Currently, commands which depend on 'parse_options_subcommand()' don't show the usage string, and instead show '(null)' $ ./perf sched Usage: (null) -D, --dump-raw-trace dump raw trace in ASCII -f, --force don't complain, do it -i, --input <file> input file name -v, --verbose be more verbose (show symbol address, etc) 'parse_options_subcommand()' is generally expected to initialise the usage string, with information in the passed 'subcommands[]' array This behaviour was changed in: 230a7a71 ("libsubcmd: Fix parse-options memory leak") Where the generated usage string is deallocated, and usage[0] string is reassigned as NULL. As discussed in [1], free the allocated usage string in the main function itself, and don't reset usage string to NULL in parse_options_subcommand With this change, the behaviour is restored. $ ./perf sched Usage: perf sched [<options>] {record|latency|map|replay|script|timehist} -D, --dump-raw-trace dump raw trace in ASCII -f, --force don't complain, do it -i, --input <file> input file name -v, --verbose be more verbose (show symbol address, etc) [1]: https://lore.kernel.org/linux-perf-users/htq5vhx6piet4nuq2mmhk7fs2bhfykv52dbppwxmo3s7du2odf@styd27tioc6e/ Fixes: 230a7a71 ("libsubcmd: Fix parse-options memory leak") Suggested-by:Aditya Gupta <adityag@linux.ibm.com> Acked-by:
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- Aug 30, 2024
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Tony Ambardar authored
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: ba451366 ("libbpf: Implement basic split BTF support") Fixes: 58e185a0 ("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:
Tony Ambardar <tony.ambardar@gmail.com> Signed-off-by:
Alan Maguire <alan.maguire@oracle.com> Acked-by:
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- Aug 29, 2024
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Andrii Nakryiko authored
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: d66562fb ("libbpf: Add BPF object skeleton support") Reported-by:
Daniel Müller <deso@posteo.net> Signed-off-by:
Daniel Borkmann <daniel@iogearbox.net> Reviewed-by:
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- Aug 15, 2024
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Sam James authored
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:
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- Aug 12, 2024
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Alan Maguire authored
License should be // SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) ...as with other libbpf files. Fixes: 19e00c89 ("libbpf: Split BTF relocation") Reported-by:
Neill Kapron <nkapron@google.com> Signed-off-by:
Yonghong Song <yonghong.song@linux.dev> Link: https://lore.kernel.org/bpf/20240810093504.2111134-1-alan.maguire@oracle.com
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- Aug 06, 2024
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Wei Yang authored
Commit 1e4c64b7 ("mm/memblock: Add "reserve_mem" to reserved named memory at boot up") introduce the usage of memparse(), which is not defined in memblock test. Add the definition and link it to fix the build. Signed-off-by:
Wei Yang <richard.weiyang@gmail.com> Link: https://lore.kernel.org/r/20240806010319.29194-3-richard.weiyang@gmail.com Signed-off-by:
Mike Rapoport (Microsoft) <rppt@kernel.org>
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- Aug 05, 2024
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Brian Norris authored
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:
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Brian Norris authored
All built targets need fixdep to be built first, before handling object dependencies [1]. We're missing one such dependency before the libsubcmd target. This resolves .cmd file generation issues such that the following sequence produces many fewer results: $ git clean -xfd tools/ $ make tools/objtool $ grep "cannot find fixdep" $(find tools/objtool -name '*.cmd') In particular, only a buggy tools/objtool/libsubcmd/.fixdep.o.cmd remains, due to circular dependencies of fixdep on itself. Such incomplete .cmd files don't usually cause a direct problem, since they're designed to fail "open", but they can cause some subtle problems that would otherwise be handled by proper fixdep'd dependency files. [2] [1] This problem is better described in commit abb26210 ("perf tools: Force fixdep compilation at the start of the build"). I don't apply its solution here, because additional recursive make can be a bit of overkill. [2] Example failure case: cp -arl linux-src linux-src2 cd linux-src2 make O=/path/to/out cd ../linux-src rm -rf ../linux-src2 make O=/path/to/out Previously, we'd see errors like: make[6]: *** No rule to make target '/path/to/linux-src2/tools/include/linux/compiler.h', needed by '/path/to/out/tools/bpf/resolve_btfids/libsubcmd/exec-cmd.o'. Stop. Now, the properly-fixdep'd .cmd files will ignore a missing /path/to/linux-src2/... Signed-off-by:
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- Aug 01, 2024
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Tiezhu Yang authored
When executing the command "perf list", I met "Error: failed to open tracing events directory" twice, the first reason is that there is no "/sys/kernel/tracing/events" directory due to it does not enable the kernel tracing infrastructure with CONFIG_FTRACE, the second reason is that there is no root privileges. Add the error string to tell the users what happened and what should to do, and also call put_tracing_file() to free events_path a little later to avoid messy code in the error message. At the same time, just remove the redundant "/" of the file path in the function get_tracing_file(), otherwise it shows something like "/sys/kernel/tracing//events". Before: $ ./perf list Error: failed to open tracing events directory After: (1) Without CONFIG_FTRACE $ ./perf list Error: failed to open tracing events directory /sys/kernel/tracing/events: No such file or directory (2) With CONFIG_FTRACE but no root privileges $ ./perf list Error: failed to open tracing events directory /sys/kernel/tracing/events: Permission denied Committer testing: Redirect stdout to null to quickly test the patch: Before: $ perf list > /dev/null Error: failed to open tracing events directory $ After: $ perf list > /dev/null Error: failed to open tracing events directory /sys/kernel/tracing/events: Permission denied $ Signed-off-by:
Tiezhu Yang <yangtiezhu@loongson.cn> Tested-by:
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Charlie Jenkins authored
Ignore files that are generated by libperf and libperf tests. Signed-off-by:
Charlie Jenkins <charlie@rivosinc.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Ian Rogers <irogers@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/lkml/20240729-libperf_gitignore-v1-1-1c70dd98edf9@rivosinc.com Signed-off-by:
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- Jul 31, 2024
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Athira Rajeev authored
Currently, the perf tool infrastructure uses the disasm_line__parse function to parse disassembled line. Example snippet from objdump: objdump --start-address=<address> --stop-address=<address> -d --no-show-raw-insn -C <vmlinux> c0000000010224b4: lwz r10,0(r9) This line "lwz r10,0(r9)" is parsed to extract instruction name, registers names and offset. In powerpc, the approach for data type profiling uses raw instruction instead of result from objdump to identify the instruction category and extract the source/target registers. Example: 38 01 81 e8 ld r4,312(r1) Here "38 01 81 e8" is the raw instruction representation. Add function "disasm_line__parse_powerpc" to handle parsing of raw instruction. Also update "struct disasm_line" to save the binary code/ With the change, function captures: line -> "38 01 81 e8 ld r4,312(r1)" raw instruction "38 01 81 e8" Raw instruction is used later to extract the reg/offset fields. Macros are added to extract opcode and register fields. "struct disasm_line" is updated to carry union of "bytes" and "raw_insn" of 32 bit to carry raw code (raw). Function "disasm_line__parse_powerpc fills the raw instruction hex value and can use macros to get opcode. There is no changes in existing code paths, which parses the disassembled code. The size of raw instruction depends on architecture. In case of powerpc, the parsing the disasm line needs to handle cases for reading binary code directly from DSO as well as parsing the objdump result. Hence adding the logic into separate function instead of updating "disasm_line__parse". The architecture using the instruction name and present approach is not altered. Since this approach targets powerpc, the macro implementation is added for powerpc as of now. Since the disasm_line__parse is used in other cases (perf annotate) and not only data tye profiling, the powerpc callback includes changes to work with binary code as well as mnemonic representation. Also in case if the DSO read fails and libcapstone is not supported, the approach fallback to use objdump as option. Hence as option, patch has changes to ensure objdump option also works well. Reviewed-by:
Kajol Jain <kjain@linux.ibm.com> Reviewed-by:
Athira Rajeev <atrajeev@linux.vnet.ibm.com> Tested-by:
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- Jul 29, 2024
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David Vernet authored
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: 590a0088 ("bpf: libbpf: Add STRUCT_OPS support") Signed-off-by:
David Vernet <void@manifault.com> Signed-off-by:
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- Jul 17, 2024
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Andrii Nakryiko authored
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: 351131b5 ("libbpf: add btf_dump API for BTF-to-C conversion") Reported-by:
Tejun Heo <tj@kernel.org> Signed-off-by:
Stanislav Fomichev <sdf@fomichev.me> Link: https://lore.kernel.org/bpf/20240712224442.282823-1-andrii@kernel.org
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- Jul 10, 2024
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Wei Yang authored
In tools/ directory, function bitmap_clear() is currently only used in object file tools/testing/radix-tree/xarray.o. But instead of keeping a bitmap.c with only bitmap_clear() definition in radix-tree's own directory, it would be more proper to put it in common directory lib/. Sync the kernel definition and link some related libs, no functional change is expected. Signed-off-by:
Yury Norov <yury.norov@gmail.com>
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Andrii Nakryiko authored
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:
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Andrii Nakryiko authored
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:
Mykyta Yatsenko <yatsenko@meta.com> Signed-off-by:
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- Jul 08, 2024
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Andreas Ziegler authored
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:
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- Jul 01, 2024
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Alan Maguire authored
Coverity points out that after calling btf__new_empty_split() the wrong value is checked for error. Fixes: 58e185a0 ("libbpf: Add btf__distill_base() creating split BTF with distilled base BTF") Reported-by:
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- Jun 26, 2024
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Alan Maguire authored
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:
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- Jun 25, 2024
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Kuan-Wei Chiu authored
Since cond_resched() is not called in userspace, remove the redundant code in userspace's list_sort() implementation. This change eliminates the unused 'count' variable and the associated logic for invoking cmp() periodically, which was intended to trigger cond_resched() in kernel space. The removed code includes: - Declaration and increment of the 'count' variable. - Conditional invocation of cmp() based on 'count'. This cleanup simplifies merge_final(), avoids unnecessary overhead, and has no impact on the functionality of list_sort() in userspace. Link: https://lkml.kernel.org/r/20240525230206.1077536-1-visitorckw@gmail.com Signed-off-by:
Kuan-Wei Chiu <visitorckw@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Ching-Chun (Jim) Huang <jserv@ccns.ncku.edu.tw> Cc: Ian Rogers <irogers@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org>
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- Jun 24, 2024
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Antoine Tenart authored
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: 3903802b ("libbpf: Add basic BTF sanity validation") Signed-off-by:
Antoine Tenart <atenart@kernel.org> Signed-off-by:
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- Jun 21, 2024
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Alan Maguire authored
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:
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Alan Maguire authored
This will allow it to be shared with the kernel. No functional change. Suggested-by:
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Alan Maguire authored
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:
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Donglin Peng authored
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: 8fd27bf6 ("libbpf: Add BPF static linker BTF and BTF.ext support") Signed-off-by:Donglin Peng <dolinux.peng@gmail.com> Signed-off-by:
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- Jun 17, 2024
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Eduard Zingerman authored
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: -
Alan Maguire authored
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:
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Alan Maguire authored
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:
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- Jun 14, 2024
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Ian Rogers authored
Previous allocation didn't account for sample ID written after the lost samples event. Switch from malloc/free to a stack allocation. Reported-by:
Milian Wolff <milian.wolff@kdab.com> Closes: https://lore.kernel.org/linux-perf-users/23879991.0LEYPuXRzz@milian-workstation/ Signed-off-by:
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- Jun 06, 2024
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Mykyta Yatsenko authored
Similarly to `bpf_program`, support `bpf_map` automatic attachment in `bpf_object__attach_skeleton`. Currently only struct_ops maps could be attached. On bpftool side, code-generate links in skeleton struct for struct_ops maps. Similarly to `bpf_program_skeleton`, set links in `bpf_map_skeleton`. On libbpf side, extend `bpf_map` with new `autoattach` field to support enabling or disabling autoattach functionality, introducing getter/setter for this field. `bpf_object__(attach|detach)_skeleton` is extended with attaching/detaching struct_ops maps logic. Signed-off-by:
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