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https://gitee.com/bianbu-linux/linux-6.6
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ba3647aa16
[ Upstream commit fe879bb42f8a6513ed18e9d22efb99cb35590201 ]
Current 'bpftool link' command does not show pids, e.g.,
$ tools/build/bpftool/bpftool link
...
4: tracing prog 23
prog_type lsm attach_type lsm_mac
target_obj_id 1 target_btf_id 31320
Hack the following change to enable normal libbpf debug output,
# --- a/tools/bpf/bpftool/pids.c
# +++ b/tools/bpf/bpftool/pids.c
# @@ -121,9 +121,9 @@ int build_obj_refs_table(struct hashmap **map, enum bpf_obj_type type)
# /* we don't want output polluted with libbpf errors if bpf_iter is not
# * supported
# */
# - default_print = libbpf_set_print(libbpf_print_none);
# + /* default_print = libbpf_set_print(libbpf_print_none); */
# err = pid_iter_bpf__load(skel);
# - libbpf_set_print(default_print);
# + /* libbpf_set_print(default_print); */
Rerun the above bpftool command:
$ tools/build/bpftool/bpftool link
libbpf: prog 'iter': BPF program load failed: Permission denied
libbpf: prog 'iter': -- BEGIN PROG LOAD LOG --
0: R1=ctx() R10=fp0
; struct task_struct *task = ctx->task; @ pid_iter.bpf.c:69
0: (79) r6 = *(u64 *)(r1 +8) ; R1=ctx() R6_w=ptr_or_null_task_struct(id=1)
; struct file *file = ctx->file; @ pid_iter.bpf.c:68
...
; struct bpf_link *link = (struct bpf_link *) file->private_data; @ pid_iter.bpf.c:103
80: (79) r3 = *(u64 *)(r8 +432) ; R3_w=scalar() R8=ptr_file()
; if (link->type == bpf_core_enum_value(enum bpf_link_type___local, @ pid_iter.bpf.c:105
81: (61) r1 = *(u32 *)(r3 +12)
R3 invalid mem access 'scalar'
processed 39 insns (limit 1000000) max_states_per_insn 0 total_states 3 peak_states 3 mark_read 2
-- END PROG LOAD LOG --
libbpf: prog 'iter': failed to load: -13
...
The 'file->private_data' returns a 'void' type and this caused subsequent 'link->type'
(insn #81) failed in verification.
To fix the issue, restore the previous BPF_CORE_READ so old kernels can also work.
With this patch, the 'bpftool link' runs successfully with 'pids'.
$ tools/build/bpftool/bpftool link
...
4: tracing prog 23
prog_type lsm attach_type lsm_mac
target_obj_id 1 target_btf_id 31320
pids systemd(1)
Fixes:
|
||
|---|---|---|
| .. | ||
| bash-completion | ||
| Documentation | ||
| skeleton | ||
| .gitignore | ||
| btf.c | ||
| btf_dumper.c | ||
| cfg.c | ||
| cfg.h | ||
| cgroup.c | ||
| common.c | ||
| feature.c | ||
| gen.c | ||
| iter.c | ||
| jit_disasm.c | ||
| json_writer.c | ||
| json_writer.h | ||
| link.c | ||
| main.c | ||
| main.h | ||
| Makefile | ||
| map.c | ||
| map_perf_ring.c | ||
| net.c | ||
| netlink_dumper.c | ||
| netlink_dumper.h | ||
| perf.c | ||
| pids.c | ||
| prog.c | ||
| struct_ops.c | ||
| tracelog.c | ||
| xlated_dumper.c | ||
| xlated_dumper.h | ||