(2015/01/10 19:33), Namhyung Kim wrote:
> The find_probe_trace_events_from_map() searches matching symbol from a
> map (so from a backing dso). For uprobes, it'll create a new map (and
> dso) and loads it using a filter. It's a little bit inefficient in that
> it'll read out the symbol table everytime but works well anyway.
>
> For kprobes however, it'll reuse existing kernel map which might be
> loaded before. In this case map__load() just returns with no result.
> It makes kprobes always failed to find symbol even if it exists in the
> map (dso).
>
> To fix it, use map__find_symbol_by_name() instead. It'll load a map
> with full symbols and sorts them by name. It needs to search sibing
> nodes since there can be multiple (local) symbols with same name. Now
> resulting symbol references are saved in the funcs list.
>
> Cc: Masami Hiramatsu <masami.hiramatsu...@hitachi.com>
> Signed-off-by: Namhyung Kim <namhy...@kernel.org>
> ---
> tools/perf/util/probe-event.c | 101
> ++++++++++++++++++++++++++++++++++++------
> 1 file changed, 87 insertions(+), 14 deletions(-)
>
> diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> index 7f9b8632e433..e5af16988791 100644
> --- a/tools/perf/util/probe-event.c
> +++ b/tools/perf/util/probe-event.c
> @@ -2191,20 +2191,86 @@ static int __add_probe_trace_events(struct
> perf_probe_event *pev,
> return ret;
> }
>
> -static char *looking_function_name;
> -static int num_matched_functions;
> +struct symbol_entry {
> + struct list_head node;
> + struct symbol *sym;
> +};
>
> -static int probe_function_filter(struct map *map __maybe_unused,
> - struct symbol *sym)
> +/* returns 1 if symbol was added, 0 if symbol was skipped, -1 if error */
> +static int add_symbol_entry(struct symbol *sym, struct list_head *head)
> {
> - if ((sym->binding == STB_GLOBAL || sym->binding == STB_LOCAL) &&
> - strcmp(looking_function_name, sym->name) == 0) {
> - num_matched_functions++;
> + struct symbol_entry *ent;
> +
> + if (sym->binding != STB_GLOBAL && sym->binding != STB_LOCAL)
> return 0;
> - }
> +
> + ent = malloc(sizeof(*ent));
> + if (ent == NULL)
> + return -1;
return -ENOMEM; ?
> +
> + ent->sym = sym;
> + list_add(&ent->node, head);
> return 1;
> }
>
> +static int find_probe_functions(struct map *map, char *name, struct
> list_head *head)
> +{
> + struct symbol *sym, *orig_sym;
> + struct symbol_entry *ent;
> + struct rb_node *node;
> + int found = 0;
> + int ret;
> +
> + sym = map__find_symbol_by_name(map, name, NULL);
> + if (sym == NULL)
> + return 0;
> +
> + ret = add_symbol_entry(sym, head);
> + if (ret < 0)
> + goto err;
> +
> + found += ret;
If ret always be 1 in successful case, we'd better do "found++" here.
And it also means we can do it shorter as below.
if (add_symbol_entry(sym, head) < 0)
goto err;
found++;
> +
> + /* search back and forth to find symbols that have same name */
Hmm, I see. but this code looks no-good sign... Can we have any generic
synonym handling routine?
Other parts looks good to me:)
Thank you,
--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu...@hitachi.com
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