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SubjectRe: [PATCH V2] perf tools: Fix maps__find_symbol_by_name()
Em Fri, Sep 07, 2018 at 11:51:16AM +0300, Adrian Hunter escreveu:
> Commit 1c5aae7710bb ("perf machine: Create maps for x86 PTI entry
> trampolines") revealed a problem with maps__find_symbol_by_name() that

Can we have this with a Fixes: 1c5aae7710bb?

So that that, combined with the CC: stable, tells which stable kernels
should get that fix, I think there are scripts harvesting Fixes: tags to
help stable maintainers :-)

- Arnaldo

> resulted in probes not being found e.g.
>
> $ sudo perf probe xsk_mmap
> xsk_mmap is out of .text, skip it.
> Probe point 'xsk_mmap' not found.
> Error: Failed to add events.
>
> maps__find_symbol_by_name() can optionally return the map of the found
> symbol. It can get the map wrong because, in fact, the symbol is found
> on the map's dso, not allowing for the possibility that the dso has more
> than one map. Fix by always checking the map contains the symbol.
>
> Reported-by: Björn Töpel <bjorn.topel@intel.com>
> Tested-by: Björn Töpel <bjorn.topel@intel.com>
> Cc: stable@vger.kernel.org
> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
> ---
>
>
> Changes in V2:
>
> Expanded commit message
> Corrected email address
>
>
> tools/perf/util/map.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
> index 3f07a587c8e6..354e54550d2b 100644
> --- a/tools/perf/util/map.c
> +++ b/tools/perf/util/map.c
> @@ -574,6 +574,13 @@ struct symbol *map_groups__find_symbol(struct map_groups *mg,
> return NULL;
> }
>
> +static bool map__contains_symbol(struct map *map, struct symbol *sym)
> +{
> + u64 ip = map->unmap_ip(map, sym->start);
> +
> + return ip >= map->start && ip < map->end;
> +}
> +
> struct symbol *maps__find_symbol_by_name(struct maps *maps, const char *name,
> struct map **mapp)
> {
> @@ -589,6 +596,10 @@ struct symbol *maps__find_symbol_by_name(struct maps *maps, const char *name,
>
> if (sym == NULL)
> continue;
> + if (!map__contains_symbol(pos, sym)) {
> + sym = NULL;
> + continue;
> + }
> if (mapp != NULL)
> *mapp = pos;
> goto out;
> --
> 2.17.1

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