lkml.org 
[lkml]   [2022]   [Feb]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH 1/1] perf: Set build-id using build-id header on new mmap records
On Thu, Feb 24, 2022 at 05:19:55PM +0000, James Clark wrote:
> MMAP records that occur after the build-id header is parsed do not have
> their build-id set even if the filename matches an entry from the
> header. Set the build-id on these dsos as long as the MMAP record
> doesn't have its own build-id set.
>
> This fixes an issue with off target analysis where the local version of
> a dso is loaded rather than one from ~/.debug via a build-id.

nice catch :)

>
> Reported-by: Denis Nikitin <denik@chromium.org>
> Signed-off-by: James Clark <james.clark@arm.com>
> ---
> tools/perf/util/dso.h | 1 +
> tools/perf/util/header.c | 1 +
> tools/perf/util/map.c | 16 ++++++++++++++--
> 3 files changed, 16 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h
> index 011da3924fc1..3a9fd4d389b5 100644
> --- a/tools/perf/util/dso.h
> +++ b/tools/perf/util/dso.h
> @@ -167,6 +167,7 @@ struct dso {
> enum dso_load_errno load_errno;
> u8 adjust_symbols:1;
> u8 has_build_id:1;
> + u8 header_build_id:1;
> u8 has_srcline:1;
> u8 hit:1;
> u8 annotate_warned:1;
> diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
> index 6da12e522edc..571d73d4f976 100644
> --- a/tools/perf/util/header.c
> +++ b/tools/perf/util/header.c
> @@ -2200,6 +2200,7 @@ static int __event_process_build_id(struct perf_record_header_build_id *bev,
>
> build_id__init(&bid, bev->data, size);
> dso__set_build_id(dso, &bid);
> + dso->header_build_id = 1;
>
> if (dso_space != DSO_SPACE__USER) {
> struct kmod_path m = { .name = NULL, };
> diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
> index 1803d3887afe..4ae91e491e23 100644
> --- a/tools/perf/util/map.c
> +++ b/tools/perf/util/map.c
> @@ -127,7 +127,7 @@ struct map *map__new(struct machine *machine, u64 start, u64 len,
>
> if (map != NULL) {
> char newfilename[PATH_MAX];
> - struct dso *dso;
> + struct dso *dso, *header_bid_dso;
> int anon, no_dso, vdso, android;
>
> android = is_android_lib(filename);
> @@ -185,7 +185,19 @@ struct map *map__new(struct machine *machine, u64 start, u64 len,
>
> if (build_id__is_defined(bid))
> dso__set_build_id(dso, bid);
> -
> + else {

nit please add { } to the if clause as well

> + /*
> + * If the mmap event had no build ID, search for an existing dso from the
> + * build ID header by name. Otherwise only the dso loaded at the time of
> + * reading the header will have the build ID set and all future mmaps will
> + * have it missing.
> + */
> + header_bid_dso = __dsos__find(&machine->dsos, filename, false);

is this 'perf top' safe? I think dso should be added in the
same thread, but please check and add comment why we don't
need locking in here

thanks,
jirka

> + if (header_bid_dso && header_bid_dso->header_build_id) {
> + dso__set_build_id(dso, &header_bid_dso->bid);
> + dso->header_build_id = 1;
> + }
> + }
> dso__put(dso);
> }
> return map;
> --
> 2.28.0
>

\
 
 \ /
  Last update: 2022-02-27 23:51    [W:0.057 / U:0.032 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site