Re: [PATCH] perf tools: Fix kernel maps for kcore and eBPF

Arnaldo Carvalho de Melo
2020-06-02T14:07:08Z

Em Tue, Jun 02, 2020 at 02:25:05PM +0300, Adrian Hunter escreveu:
> Adjust pgoff also when moving a map's start address.
>
> Example with v5.4.34 based kernel:
>
> Before:
>
> $ sudo tools/perf/perf record -a --kcore -e intel_pt//k sleep 1
> [ perf record: Woken up 1 times to write data ]
> [ perf record: Captured and wrote 1.958 MB perf.data ]
> $ sudo tools/perf/perf script --itrace=e >/dev/null
> Warning:
> 961 instruction trace errors
>
> After:
>
> $ sudo tools/perf/perf script --itrace=e >/dev/null
> $

Thanks, tested on a kaby lake system (i5-7500) and applied,

- Arnaldo

> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
> Fixes: fb5a88d4131a ("perf tools: Preserve eBPF maps when loading kcore")
> Cc: stable@vger.kernel.org
> ---
> tools/perf/util/symbol.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
> index 57cbe7a29868..5ddf84dcbae7 100644
> --- a/tools/perf/util/symbol.c
> +++ b/tools/perf/util/symbol.c
> @@ -1224,6 +1224,7 @@ int maps__merge_in(struct maps *kmaps, struct map *new_map)
>
> m->end = old_map->start;
> list_add_tail(&m->node, &merged);
> + new_map->pgoff += old_map->end - new_map->start;
> new_map->start = old_map->end;
> }
> } else {
> @@ -1244,6 +1245,7 @@ int maps__merge_in(struct maps *kmaps, struct map *new_map)
> * |new......| -> |new...|
> * |old....| -> |old....|
> */
> + new_map->pgoff += old_map->end - new_map->start;
> new_map->start = old_map->end;
> }
> }
> --
> 2.17.1
>

--

- Arnaldo