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

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Date:   Tue,  2 Jun 2020 14:25:05 +0300
From:   Adrian Hunter <adrian.hunter@...el.com>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:     Jiri Olsa <jolsa@...hat.com>, linux-kernel@...r.kernel.org
Subject: [PATCH] perf tools: Fix kernel maps for kcore and eBPF

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
    $

Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
Fixes: fb5a88d4131a ("perf tools: Preserve eBPF maps when loading kcore")
Cc: stable@...r.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