2023-06-23 14:15 UTC+0000 ~ Yafang Shao <laoar.shao@xxxxxxxxx>
> Show the already expose kprobe_multi link info in bpftool. The result as
> follows,
>
> $ tools/bpf/bpftool/bpftool link show
> 4: kprobe_multi prog 22
> kprobe.multi func_cnt 7
> addr func [module]
> ffffffffbbc44f20 schedule_timeout_interruptible
> ffffffffbbc44f60 schedule_timeout_killable
> ffffffffbbc44fa0 schedule_timeout_uninterruptible
> ffffffffbbc44fe0 schedule_timeout_idle
> ffffffffc08028d0 xfs_trans_get_efd [xfs]
> ffffffffc080fa10 xfs_trans_get_buf_map [xfs]
> ffffffffc0813320 xfs_trans_get_dqtrx [xfs]
> pids kprobe_multi(1434978)
> 5: kprobe_multi prog 22
> kretprobe.multi func_cnt 7
> addr func [module]
> ffffffffbbc44f20 schedule_timeout_interruptible
> ffffffffbbc44f60 schedule_timeout_killable
> ffffffffbbc44fa0 schedule_timeout_uninterruptible
> ffffffffbbc44fe0 schedule_timeout_idle
> ffffffffc08028d0 xfs_trans_get_efd [xfs]
> ffffffffc080fa10 xfs_trans_get_buf_map [xfs]
> ffffffffc0813320 xfs_trans_get_dqtrx [xfs]
> pids kprobe_multi(1434978)
>
> $ tools/bpf/bpftool/bpftool link show -j
> [{"id":4,"type":"kprobe_multi","prog_id":22,"retprobe":false,"func_cnt":7,"funcs":[{"addr":18446744072564789024,"func":"schedule_timeout_interruptible","module":""},{"addr":18446744072564789088,"func":"schedule_timeout_killable","module":""},{"addr":18446744072564789152,"func":"schedule_timeout_uninterruptible","module":""},{"addr":18446744072564789216,"func":"schedule_timeout_idle","module":""},{"addr":18446744072644208848,"func":"xfs_trans_get_efd","module":"xfs"},{"addr":18446744072644262416,"func":"xfs_trans_get_buf_map","module":"xfs"},{"addr":18446744072644277024,"func":"xfs_trans_get_dqtrx","module":"xfs"}],"pids":[{"pid":1434978,"comm":"kprobe_multi"}]},{"id":5,"type":"kprobe_multi","prog_id":22,"retprobe":true,"func_cnt":7,"funcs":[{"addr":18446744072564789024,"func":"schedule_timeout_interruptible","module":""},{"addr":18446744072564789088,"func":"schedule_timeout_killable","module":""},{"addr":18446744072564789152,"func":"schedule_timeout_uninterruptible","module":""},{"addr":18446744072564789216,"func":"schedule_timeout_idle","module":""},{"addr":18446744072644208848,"func":"xfs_trans_get_efd","module":"xfs"},{"addr":18446744072644262416,"func":"xfs_trans_get_buf_map","module":"xfs"},{"addr":18446744072644277024,"func":"xfs_trans_get_dqtrx","module":"xfs"}],"pids":[{"pid":1434978,"comm":"kprobe_multi"}]}]
>
> When kptr_restrict is 2, the result is,
>
> $ tools/bpf/bpftool/bpftool link show
> 4: kprobe_multi prog 22
> kprobe.multi func_cnt 7
> 5: kprobe_multi prog 22
> kretprobe.multi func_cnt 7
>
> Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
> ---
> tools/bpf/bpftool/link.c | 109 ++++++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 108 insertions(+), 1 deletion(-)
>
> diff --git a/tools/bpf/bpftool/link.c b/tools/bpf/bpftool/link.c
> index 2d78607..8461e6d 100644
> --- a/tools/bpf/bpftool/link.c
> +++ b/tools/bpf/bpftool/link.c
> @@ -14,8 +14,10 @@
>
> #include "json_writer.h"
> #include "main.h"
> +#include "xlated_dumper.h"
>
> static struct hashmap *link_table;
> +static struct dump_data dd = {};
>
> static int link_parse_fd(int *argc, char ***argv)
> {
> @@ -166,6 +168,45 @@ static int get_prog_info(int prog_id, struct bpf_prog_info *info)
> return err;
> }
>
> +static int cmp_u64(const void *A, const void *B)
> +{
> + const __u64 *a = A, *b = B;
> +
> + return *a - *b;
> +}
> +
> +static void
> +show_kprobe_multi_json(struct bpf_link_info *info, json_writer_t *wtr)
> +{
> + __u32 i, j = 0;
> + __u64 *addrs;
> +
> + jsonw_bool_field(json_wtr, "retprobe",
> + info->kprobe_multi.flags & BPF_F_KPROBE_MULTI_RETURN);
> + jsonw_uint_field(json_wtr, "func_cnt", info->kprobe_multi.count);
> + jsonw_name(json_wtr, "funcs");
> + jsonw_start_array(json_wtr);
> + addrs = (__u64 *)u64_to_ptr(info->kprobe_multi.addrs);
> + qsort((void *)addrs, info->kprobe_multi.count, sizeof(__u64), cmp_u64);
> +
> + /* Load it once for all. */
> + if (!dd.sym_count)
> + kernel_syms_load(&dd);
> + for (i = 0; i < dd.sym_count; i++) {
> + if (dd.sym_mapping[i].address != addrs[j])
> + continue;
> + jsonw_start_object(json_wtr);
> + jsonw_uint_field(json_wtr, "addr", dd.sym_mapping[i].address);
> + jsonw_string_field(json_wtr, "func", dd.sym_mapping[i].name);
> + /* Print none if it is vmlinux */
> + jsonw_string_field(json_wtr, "module", dd.sym_mapping[i].module);
We could maybe print null ("jsonw_null(json_wtr);") instead of an empty
string here when we have no module name. Although I'm not sure it
matters too much. Let's see whether the series needs another respin.
Anyway:
Reviewed-by: Quentin Monnet <quentin@xxxxxxxxxxxxx>
