perf machine: Fix leak of kernel dso

The kernel dso may be found by searching dsos or allocating if not
found. The allocation returns with a reference count of 2, once for
the dsos list and once for the returned value. The list search has a
reference count of 1, once for the dsos list. To make the reference
counts consistent, increase the dsos list search reference count to 2
with a dso__get, and do a put when the scope ends for either the
allocated or found dso.

This issue was found with leak sanitizer and reference count checking.

Signed-off-by: Ian Rogers <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Ali Saidi <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Athira Rajeev <[email protected]>
Cc: Brian Robbins <[email protected]>
Cc: Changbin Du <[email protected]>
Cc: Dmitrii Dolgov <[email protected]>
Cc: Fangrui Song <[email protected]>
Cc: German Gomez <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Ivan Babrou <[email protected]>
Cc: James Clark <[email protected]>
Cc: Jing Zhang <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: John Garry <[email protected]>
Cc: K Prateek Nayak <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: Leo Yan <[email protected]>
Cc: Liam Howlett <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Miguel Ojeda <[email protected]>
Cc: Mike Leach <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Naveen N. Rao <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Ravi Bangoria <[email protected]>
Cc: Sean Christopherson <[email protected]>
Cc: Steinar H. Gunderson <[email protected]>
Cc: Suzuki Poulouse <[email protected]>
Cc: Wenyu Liu <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Yang Jihong <[email protected]>
Cc: Ye Xingchen <[email protected]>
Cc: Yuan Can <[email protected]>
Cc: [email protected]
Cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

1 files changed, 2 insertions, 1 deletions

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 46af5e9748c9..f8e6c07f0048 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -1868,7 +1868,7 @@ static int machine__process_kernel_mmap_event(struct machine *machine,
 				continue;
 
 
-			kernel = dso;
+			kernel = dso__get(dso);
 			break;
 		}
 
@@ -1913,6 +1913,7 @@ static int machine__process_kernel_mmap_event(struct machine *machine,
 			 */
 			dso__load(kernel, machine__kernel_map(machine));
 		}
+		dso__put(kernel);
 	} else if (perf_event__is_extra_kernel_mmap(machine, xm)) {
 		return machine__process_extra_kernel_map(machine, xm);
 	}