On Sat, Jun 24, 2023 at 12:49 AM Quentin Monnet <quentin@xxxxxxxxxxxxx> wrote:
>
> 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.
Will change it. Thanks for your review.
>
> Anyway:
>
> Reviewed-by: Quentin Monnet <quentin@xxxxxxxxxxxxx>
--
Regards
Yafang
