[tip:perf/core] perf tools: Fix split_kallsyms_for_kcore() for trampoline symbols

[tip-bot for Adrian Hunter]

Commit-ID:  d6d457451eb94fa747dc202765592eb8885a7352
Gitweb:     https://git.kernel.org/tip/d6d457451eb94fa747dc202765592eb8885a7352
Author:     Adrian Hunter <adrian.hunter@xxxxxxxxx>
AuthorDate: Wed, 9 Jan 2019 11:18:30 +0200
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Wed, 6 Feb 2019 10:00:40 -0300

perf tools: Fix split_kallsyms_for_kcore() for trampoline symbols

Kallsyms symbols do not have a size, so the size becomes the distance to
the next symbol.

Consequently the recently added trampoline symbols end up with large
sizes because the trampolines are some distance from one another and the
main kernel map.

However, symbols that end outside their map can disrupt the symbol tree
because, after mapping, it can appear incorrectly that they overlap
other symbols.

Add logic to truncate symbol size to the end of the corresponding map.

Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Fixes: d83212d5dd67 ("kallsyms, x86: Export addresses of PTI entry trampolines")
Link: http://lkml.kernel.org/r/20190109091835.5570-2-adrian.hunter@xxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 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 7b194cf53cc0..758bf5f74e6e 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -718,6 +718,8 @@ static int map_groups__split_kallsyms_for_kcore(struct map_groups *kmaps, struct
 		}
 
 		pos->start -= curr_map->start - curr_map->pgoff;
+		if (pos->end > curr_map->end)
+			pos->end = curr_map->end;
 		if (pos->end)
 			pos->end -= curr_map->start - curr_map->pgoff;
 		symbols__insert(&curr_map->dso->symbols, pos);