6.9-stable review patch. If anyone has any objections, please let me know.
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From: James Clark james.clark@arm.com
[ Upstream commit f30232b20fadea8c0f2f43f764bc06e51e8cfcdf ]
When loading kcore, the main vmlinux map is updated in the same loop that merges the remaining maps. If a map that overlaps is merged in before kcore, the list can become unsortable when the main map addresses are updated. This will later trigger the check_invariants() assert:
$ perf record $ perf report
util/maps.c:96: check_invariants: Assertion `map__end(prev) <= map__start(map) || map__start(prev) == map__start(map)' failed. Aborted
Fix it by moving the main map update prior to the loop so that maps__merge_in() can split it if necessary.
Fixes: 659ad3492b913c90 ("perf maps: Switch from rbtree to lazily sorted array for addresses") Signed-off-by: James Clark james.clark@arm.com Cc: Adrian Hunter adrian.hunter@intel.com Cc: Alexander Shishkin alexander.shishkin@linux.intel.com Cc: Athira Rajeev atrajeev@linux.vnet.ibm.com Cc: Ian Rogers irogers@google.com Cc: Ingo Molnar mingo@redhat.com Cc: Jiri Olsa jolsa@kernel.org Cc: Mark Rutland mark.rutland@arm.com Cc: Namhyung Kim namhyung@kernel.org Cc: Peter Zijlstra peterz@infradead.org Link: https://lore.kernel.org/r/20240507141210.195939-4-james.clark@arm.com Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- tools/perf/util/symbol.c | 40 +++++++++++++++++++++------------------- 1 file changed, 21 insertions(+), 19 deletions(-)
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c index cd825241e07d9..a1ca1b8156fe5 100644 --- a/tools/perf/util/symbol.c +++ b/tools/perf/util/symbol.c @@ -1287,7 +1287,7 @@ static int dso__load_kcore(struct dso *dso, struct map *map, { struct maps *kmaps = map__kmaps(map); struct kcore_mapfn_data md; - struct map *replacement_map = NULL; + struct map *map_ref, *replacement_map = NULL; struct machine *machine; bool is_64_bit; int err, fd; @@ -1365,6 +1365,24 @@ static int dso__load_kcore(struct dso *dso, struct map *map, if (!replacement_map) replacement_map = list_entry(md.maps.next, struct map_list_node, node)->map;
+ /* + * Update addresses of vmlinux map. Re-insert it to ensure maps are + * correctly ordered. Do this before using maps__merge_in() for the + * remaining maps so vmlinux gets split if necessary. + */ + map_ref = map__get(map); + maps__remove(kmaps, map_ref); + + map__set_start(map_ref, map__start(replacement_map)); + map__set_end(map_ref, map__end(replacement_map)); + map__set_pgoff(map_ref, map__pgoff(replacement_map)); + map__set_mapping_type(map_ref, map__mapping_type(replacement_map)); + + err = maps__insert(kmaps, map_ref); + map__put(map_ref); + if (err) + goto out_err; + /* Add new maps */ while (!list_empty(&md.maps)) { struct map_list_node *new_node = list_entry(md.maps.next, struct map_list_node, node); @@ -1372,24 +1390,8 @@ static int dso__load_kcore(struct dso *dso, struct map *map,
list_del_init(&new_node->node);
- if (RC_CHK_EQUAL(new_map, replacement_map)) { - struct map *map_ref; - - /* Ensure maps are correctly ordered */ - map_ref = map__get(map); - maps__remove(kmaps, map_ref); - - map__set_start(map_ref, map__start(new_map)); - map__set_end(map_ref, map__end(new_map)); - map__set_pgoff(map_ref, map__pgoff(new_map)); - map__set_mapping_type(map_ref, map__mapping_type(new_map)); - - err = maps__insert(kmaps, map_ref); - map__put(map_ref); - map__put(new_map); - if (err) - goto out_err; - } else { + /* skip if replacement_map, already inserted above */ + if (!RC_CHK_EQUAL(new_map, replacement_map)) { /* * Merge kcore map into existing maps, * and ensure that current maps (eBPF)