kernel.git/tools/bpf/bpftool/xlated_dumper.c, branch master

bpftool: Using the right format specifiers

2025-03-17T20:50:56Z

Fixed some formatting specifiers errors, such as using %d for int and %u for unsigned int, as well as other byte-length types. Perform type cast using the type derived from the data type itself, for example, if it's originally an int, it will be cast to unsigned int if forced to unsigned. Signed-off-by: Jiayuan Chen Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20250311112809.81901-3-jiayuan.chen@linux.dev

tools/bpf: Fix the wrong format specifier

2024-07-30T20:41:20Z

The format specifier of "unsigned int" in printf() should be "%u", not "%d". Signed-off-by: Zhu Jun Signed-off-by: Andrii Nakryiko Acked-by: Quentin Monnet Link: https://lore.kernel.org/bpf/20240724111120.11625-1-zhujun2@cmss.chinamobile.com

bpftool: Dump the kernel symbol's module name

2023-07-12T03:07:50Z

If the kernel symbol is in a module, we will dump the module name as well. The square brackets around the module name are trimmed. Signed-off-by: Yafang Shao Reviewed-by: Quentin Monnet Acked-by: Jiri Olsa Link: https://lore.kernel.org/r/20230709025630.3735-3-laoar.shao@gmail.com Signed-off-by: Alexei Starovoitov

bpftool: Support printing opcodes and source file references in CFG

2023-04-06T04:27:27Z

Add support for displaying opcodes or/and file references (filepath, line and column numbers) when dumping the control flow graphs of loaded BPF programs with bpftool. The filepaths in the records are absolute. To avoid blocks on the graph to get too wide, we truncate them when they get too long (but we always keep the entire file name). In the unlikely case where the resulting file name is ambiguous, it remains possible to get the full path with a regular dump (no CFG). Signed-off-by: Quentin Monnet Link: https://lore.kernel.org/r/20230405132120.59886-7-quentin@isovalent.com Signed-off-by: Alexei Starovoitov

bpftool: Support inline annotations when dumping the CFG of a program

2023-04-06T04:27:27Z

We support dumping the control flow graph of loaded programs to the DOT format with bpftool, but so far this feature wouldn't display the source code lines available through BTF along with the eBPF bytecode. Let's add support for these annotations, to make it easier to read the graph. In prog.c, we move the call to dump_xlated_cfg() in order to pass and use the full struct dump_data, instead of creating a minimal one in draw_bb_node(). We pass the pointer to this struct down to dump_xlated_for_graph() in xlated_dumper.c, where most of the logics is added. We deal with BTF mostly like we do for plain or JSON output, except that we cannot use a "nr_skip" value to skip a given number of linfo records (we don't process the BPF instructions linearly, and apart from the root of the graph we don't know how many records we should skip, so we just store the last linfo and make sure the new one we find is different before printing it). When printing the source instructions to the label of a DOT graph node, there are a few subtleties to address. We want some special newline markers, and there are some characters that we must escape. To deal with them, we introduce a new dedicated function btf_dump_linfo_dotlabel() in btf_dumper.c. We'll reuse this function in a later commit to format the filepath, line, and column references as well. Signed-off-by: Quentin Monnet Link: https://lore.kernel.org/r/20230405132120.59886-4-quentin@isovalent.com Signed-off-by: Alexei Starovoitov

bpftool: Fix bug for long instructions in program CFG dumps

2023-04-06T04:27:27Z

When dumping the control flow graphs for programs using the 16-byte long load instruction, we need to skip the second part of this instruction when looking for the next instruction to process. Otherwise, we end up printing "BUG_ld_00" from the kernel disassembler in the CFG. Fixes: efcef17a6d65 ("tools: bpftool: generate .dot graph from CFG information") Signed-off-by: Quentin Monnet Link: https://lore.kernel.org/r/20230405132120.59886-3-quentin@isovalent.com Signed-off-by: Alexei Starovoitov

bpftool: Define _GNU_SOURCE only once

2022-10-25T17:11:56Z

_GNU_SOURCE is defined in several source files for bpftool, but only one of them takes the precaution of checking whether the value is already defined. Add #ifndef for other occurrences too. This is in preparation for the support of disassembling JIT-ed programs with LLVM, with $(llvm-config --cflags) passing -D_GNU_SOURCE as a compilation argument. Signed-off-by: Quentin Monnet Tested-by: Niklas Söderlund Acked-by: Song Liu Link: https://lore.kernel.org/r/20221025150329.97371-2-quentin@isovalent.com Signed-off-by: Alexei Starovoitov

bpftool: Remove usage of reallocarray()

2022-02-23T21:55:01Z

This commit fixes a compilation error on systems with glibc < 2.26 [0]: ``` In file included from main.h:14:0, from gen.c:24: linux/tools/include/tools/libc_compat.h:11:21: error: attempt to use poisoned "reallocarray" static inline void *reallocarray(void *ptr, size_t nmemb, size_t size) ``` This happens because gen.c pulls , and then (through main.h). When COMPAT_NEED_REALLOCARRAY is set, libc_compat.h defines reallocarray() which libbpf_internal.h poisons with a GCC pragma. This commit reuses libbpf_reallocarray() implemented in commit 029258d7b228 ("libbpf: Remove any use of reallocarray() in libbpf"). v1 -> v2: - reuse libbpf_reallocarray() instead of reimplementing it Fixes: a9caaba399f9 ("bpftool: Implement "gen min_core_btf" logic") Reported-by: Quentin Monnet Signed-off-by: Mauricio Vásquez Signed-off-by: Andrii Nakryiko Reviewed-by: Quentin Monnet Acked-by: Song Liu Link: https://lore.kernel.org/bpf/20220221125617.39610-1-mauricio@kinvolk.io [0]: https://lore.kernel.org/bpf/3bf2bd49-9f2d-a2df-5536-bc0dde70a83b@isovalent.com/

bpftool: Use syscall/loader program in "prog load" and "gen skeleton" command.

2021-05-18T22:41:31Z

Add -L flag to bpftool to use libbpf gen_trace facility and syscall/loader program for skeleton generation and program loading. "bpftool gen skeleton -L" command will generate a "light skeleton" or "loader skeleton" that is similar to existing skeleton, but has one major difference: $ bpftool gen skeleton lsm.o > lsm.skel.h $ bpftool gen skeleton -L lsm.o > lsm.lskel.h $ diff lsm.skel.h lsm.lskel.h @@ -5,34 +4,34 @@ #define __LSM_SKEL_H__ #include -#include +#include The light skeleton does not use majority of libbpf infrastructure. It doesn't need libelf. It doesn't parse .o file. It only needs few sys_bpf wrappers. All of them are in bpf/bpf.h file. In future libbpf/bpf.c can be inlined into bpf.h, so not even libbpf.a would be needed to work with light skeleton. "bpftool prog load -L file.o" command is introduced for debugging of syscall/loader program generation. Just like the same command without -L it will try to load the programs from file.o into the kernel. It won't even try to pin them. "bpftool prog load -L -d file.o" command will provide additional debug messages on how syscall/loader program was generated. Also the execution of syscall/loader program will use bpf_trace_printk() for each step of loading BTF, creating maps, and loading programs. The user can do "cat /.../trace_pipe" for further debug. An example of fexit_sleep.lskel.h generated from progs/fexit_sleep.c: struct fexit_sleep { struct bpf_loader_ctx ctx; struct { struct bpf_map_desc bss; } maps; struct { struct bpf_prog_desc nanosleep_fentry; struct bpf_prog_desc nanosleep_fexit; } progs; struct { int nanosleep_fentry_fd; int nanosleep_fexit_fd; } links; struct fexit_sleep__bss { int pid; int fentry_cnt; int fexit_cnt; } *bss; }; Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210514003623.28033-18-alexei.starovoitov@gmail.com

bpftool: Print subprog address properly

2021-02-26T21:23:53Z

With later hashmap example, using bpftool xlated output may look like: int dump_task(struct bpf_iter__task * ctx): ; struct task_struct *task = ctx->task; 0: (79) r2 = *(u64 *)(r1 +8) ; if (task == (void *)0 || called > 0) ... 19: (18) r2 = subprog[+17] 30: (18) r2 = subprog[+25] ... 36: (95) exit __u64 check_hash_elem(struct bpf_map * map, __u32 * key, __u64 * val, struct callback_ctx * data): ; struct bpf_iter__task *ctx = data->ctx; 37: (79) r5 = *(u64 *)(r4 +0) ... 55: (95) exit __u64 check_percpu_elem(struct bpf_map * map, __u32 * key, __u64 * val, void * unused): ; check_percpu_elem(struct bpf_map *map, __u32 *key, __u64 *val, void *unused) 56: (bf) r6 = r3 ... 83: (18) r2 = subprog[-47] Signed-off-by: Yonghong Song Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210226204931.3885458-1-yhs@fb.com