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Subject[PATCH 5.7 376/376] perf symbols: Fix kernel maps for kcore and eBPF
Date
From: Adrian Hunter <adrian.hunter@intel.com>

commit 0affd0e5262b6d40f5f63466d88933e99698e240 upstream.

Adjust 'map->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
$

Committer testing:

# uname -a
Linux seventh 5.6.10-100.fc30.x86_64 #1 SMP Mon May 4 15:36:44 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
#

Before:

# perf record -a --kcore -e intel_pt//k sleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.923 MB perf.data ]
# perf script --itrace=e >/dev/null
Warning:
295 instruction trace errors
#

After:

# perf record -a --kcore -e intel_pt//k sleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.919 MB perf.data ]
# perf script --itrace=e >/dev/null
#

Fixes: fb5a88d4131a ("perf tools: Preserve eBPF maps when loading kcore")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: stable@vger.kernel.org
Link: http://lore.kernel.org/lkml/20200602112505.1406-1-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
tools/perf/util/symbol.c | 2 ++
1 file changed, 2 insertions(+)

--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -1210,6 +1210,7 @@ int maps__merge_in(struct maps *kmaps, s

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 {
@@ -1230,6 +1231,7 @@ int maps__merge_in(struct maps *kmaps, s
* |new......| -> |new...|
* |old....| -> |old....|
*/
+ new_map->pgoff += old_map->end - new_map->start;
new_map->start = old_map->end;
}
}

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