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Date:   Thu,  8 Jun 2023 16:28:15 -0700
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Subject: [PATCH v2 18/26] perf machine: Fix leak of kernel dso
From:   Ian Rogers <irogers@google.com>
To:     John Garry <john.g.garry@oracle.com>,
        Will Deacon <will@kernel.org>,
        James Clark <james.clark@arm.com>,
        Mike Leach <mike.leach@linaro.org>,
        Leo Yan <leo.yan@linaro.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Ian Rogers <irogers@google.com>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>,
        Kan Liang <kan.liang@linux.intel.com>,
        German Gomez <german.gomez@arm.com>,
        Ali Saidi <alisaidi@amazon.com>,
        Jing Zhang <renyu.zj@linux.alibaba.com>,
        Athira Rajeev <atrajeev@linux.vnet.ibm.com>,
        Miguel Ojeda <ojeda@kernel.org>,
        ye xingchen <ye.xingchen@zte.com.cn>,
        Liam Howlett <liam.howlett@oracle.com>,
        Dmitrii Dolgov <9erthalion6@gmail.com>,
        Yang Jihong <yangjihong1@huawei.com>,
        K Prateek Nayak <kprateek.nayak@amd.com>,
        Changbin Du <changbin.du@huawei.com>,
        Ravi Bangoria <ravi.bangoria@amd.com>,
        Sean Christopherson <seanjc@google.com>,
        Andi Kleen <ak@linux.intel.com>,
        "Steinar H. Gunderson" <sesse@google.com>,
        Yuan Can <yuancan@huawei.com>,
        Brian Robbins <brianrob@linux.microsoft.com>,
        liuwenyu <liuwenyu7@huawei.com>,
        Ivan Babrou <ivan@cloudflare.com>,
        Fangrui Song <maskray@google.com>,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
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Precedence: bulk

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 <irogers@google.com>
---
 tools/perf/util/machine.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

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);
 	}
-- 
2.41.0.162.gfafddb0af9-goog