[PATCH 4/4] perf report: Fix return value when loading PE DSO

[PATCH 4/4] perf report: Fix return value when loading PE DSO

[Nicholas Fraser]

The first time dso__load() was called on a PE file it always returned -1
error. This caused the first call to map__find_symbol() to always fail
on a PE file so the first sample from each PE file always had symbol
<unknown>. Subsequent samples succeed however because the DSO is already
loaded.

This fixes dso__load() to return 0 when successfully loading a DSO with
libbfd.

Signed-off-by: Nicholas Fraser <nfraser@codeweavers.com>
---
 tools/perf/util/symbol.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index aa9ae875b995..492c873713cc 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -1861,8 +1861,10 @@ int dso__load(struct dso *dso, struct map *map)
 		if (nsexit)
 			nsinfo__mountns_enter(dso->nsinfo, &nsc);
 
-		if (bfdrc == 0)
+		if (bfdrc == 0) {
+			ret = 0;
 			break;
+		}
 
 		if (!is_reg || sirc < 0)
 			continue;
-- 
2.30.0

Re: [PATCH 4/4] perf report: Fix return value when loading PE DSO

[Arnaldo Carvalho de Melo]

Em Wed, Feb 10, 2021 at 02:18:02PM -0500, Nicholas Fraser escreveu:
> The first time dso__load() was called on a PE file it always returned -1
> error. This caused the first call to map__find_symbol() to always fail
> on a PE file so the first sample from each PE file always had symbol
> <unknown>. Subsequent samples succeed however because the DSO is already
> loaded.
> 
> This fixes dso__load() to return 0 when successfully loading a DSO with
> libbfd.

You forgot to add this:

Fixes: eac9a4342e5447ca ("perf symbols: Try reading the symbol table with libbfd")

This helps, for instance, the stable@kernel.org guys, since their
scripts will scrape this and find that it should also go to whatever
stable releases are based on:

  $ git tag --contains eac9a4342e5447ca | grep ^v[45].* | grep -v -- -rc
  v5.10
  $

Applied and added the Fixes tag,

- Arnaldo
 
> Signed-off-by: Nicholas Fraser <nfraser@codeweavers.com>
> ---
>  tools/perf/util/symbol.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
> index aa9ae875b995..492c873713cc 100644
> --- a/tools/perf/util/symbol.c
> +++ b/tools/perf/util/symbol.c
> @@ -1861,8 +1861,10 @@ int dso__load(struct dso *dso, struct map *map)
>  		if (nsexit)
>  			nsinfo__mountns_enter(dso->nsinfo, &nsc);
>  
> -		if (bfdrc == 0)
> +		if (bfdrc == 0) {
> +			ret = 0;
>  			break;
> +		}
>  
>  		if (!is_reg || sirc < 0)
>  			continue;
> -- 
> 2.30.0
> 

-- 

- Arnaldo