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Date:   Wed,  6 Dec 2023 17:17:20 -0800
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Subject: [PATCH v6 46/47] perf dso: Reference counting related fixes
From:   Ian Rogers <irogers@google.com>
To:     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>,
        Nick Terrell <terrelln@fb.com>,
        Kan Liang <kan.liang@linux.intel.com>,
        Andi Kleen <ak@linux.intel.com>,
        Kajol Jain <kjain@linux.ibm.com>,
        Athira Rajeev <atrajeev@linux.vnet.ibm.com>,
        Huacai Chen <chenhuacai@kernel.org>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Vincent Whitchurch <vincent.whitchurch@axis.com>,
        "Steinar H. Gunderson" <sesse@google.com>,
        Liam Howlett <liam.howlett@oracle.com>,
        Miguel Ojeda <ojeda@kernel.org>,
        Colin Ian King <colin.i.king@gmail.com>,
        Dmitrii Dolgov <9erthalion6@gmail.com>,
        Yang Jihong <yangjihong1@huawei.com>,
        Ming Wang <wangming01@loongson.cn>,
        James Clark <james.clark@arm.com>,
        K Prateek Nayak <kprateek.nayak@amd.com>,
        Sean Christopherson <seanjc@google.com>,
        Leo Yan <leo.yan@linaro.org>,
        Ravi Bangoria <ravi.bangoria@amd.com>,
        German Gomez <german.gomez@arm.com>,
        Changbin Du <changbin.du@huawei.com>,
        Paolo Bonzini <pbonzini@redhat.com>, Li Dong <lidong@vivo.com>,
        Sandipan Das <sandipan.das@amd.com>,
        liuwenyu <liuwenyu7@huawei.com>, linux-kernel@vger.kernel.org,
        linux-perf-users@vger.kernel.org,
        Guilherme Amadio <amadio@gentoo.org>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

Ensure gets and puts are better aligned fixing reference couting
checking problems.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/util/machine.c    |  4 ++--
 tools/perf/util/map.c        |  1 +
 tools/perf/util/symbol-elf.c | 38 +++++++++++++++++-------------------
 3 files changed, 21 insertions(+), 22 deletions(-)

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 49b8ccd5affe..2dbb7b06b117 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -682,7 +682,7 @@ static int machine__process_ksymbol_register(struct machine *machine,
 					     struct perf_sample *sample __maybe_unused)
 {
 	struct symbol *sym;
-	struct dso *dso;
+	struct dso *dso = NULL;
 	struct map *map = maps__find(machine__kernel_maps(machine), event->ksymbol.addr);
 	int err = 0;
 
@@ -695,7 +695,6 @@ static int machine__process_ksymbol_register(struct machine *machine,
 		}
 		dso__set_kernel(dso, DSO_SPACE__KERNEL);
 		map = map__new2(0, dso);
-		dso__put(dso);
 		if (!map) {
 			err = -ENOMEM;
 			goto out;
@@ -734,6 +733,7 @@ static int machine__process_ksymbol_register(struct machine *machine,
 	dso__insert_symbol(dso, sym);
 out:
 	map__put(map);
+	dso__put(dso);
 	return err;
 }
 
diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index 14fb8cf65b13..4480134ef4ea 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -200,6 +200,7 @@ struct map *map__new(struct machine *machine, u64 start, u64 len,
 				dso__set_build_id(dso, dso__bid(header_bid_dso));
 				dso__set_header_build_id(dso, 1);
 			}
+			dso__put(header_bid_dso);
 		}
 		dso__put(dso);
 	}
diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index de73f9fb3fe4..4c00463abb7e 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -1366,7 +1366,7 @@ void __weak arch__sym_update(struct symbol *s __maybe_unused,
 static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
 				      GElf_Sym *sym, GElf_Shdr *shdr,
 				      struct maps *kmaps, struct kmap *kmap,
-				      struct dso **curr_dsop, struct map **curr_mapp,
+				      struct dso **curr_dsop,
 				      const char *section_name,
 				      bool adjust_kernel_syms, bool kmodule, bool *remap_kernel)
 {
@@ -1416,8 +1416,8 @@ static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
 			map__set_pgoff(map, shdr->sh_offset);
 		}
 
-		*curr_mapp = map;
-		*curr_dsop = dso;
+		dso__put(*curr_dsop);
+		*curr_dsop = dso__get(dso);
 		return 0;
 	}
 
@@ -1442,10 +1442,10 @@ static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
 		dso__set_binary_type(curr_dso, dso__binary_type(dso));
 		dso__set_adjust_symbols(curr_dso, dso__adjust_symbols(dso));
 		curr_map = map__new2(start, curr_dso);
-		dso__put(curr_dso);
-		if (curr_map == NULL)
+		if (curr_map == NULL) {
+			dso__put(curr_dso);
 			return -1;
-
+		}
 		if (dso__kernel(curr_dso))
 			map__kmap(curr_map)->kmaps = kmaps;
 
@@ -1459,21 +1459,15 @@ static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
 		dso__set_symtab_type(curr_dso, dso__symtab_type(dso));
 		if (maps__insert(kmaps, curr_map))
 			return -1;
-		/*
-		 * Add it before we drop the reference to curr_map, i.e. while
-		 * we still are sure to have a reference to this DSO via
-		 * *curr_map->dso.
-		 */
 		dsos__add(&maps__machine(kmaps)->dsos, curr_dso);
-		/* kmaps already got it */
-		map__put(curr_map);
 		dso__set_loaded(curr_dso);
-		*curr_mapp = curr_map;
+		dso__put(*curr_dsop);
 		*curr_dsop = curr_dso;
 	} else {
-		*curr_dsop = map__dso(curr_map);
-		map__put(curr_map);
+		dso__put(*curr_dsop);
+		*curr_dsop = dso__get(map__dso(curr_map));
 	}
+	map__put(curr_map);
 
 	return 0;
 }
@@ -1484,8 +1478,7 @@ dso__load_sym_internal(struct dso *dso, struct map *map, struct symsrc *syms_ss,
 {
 	struct kmap *kmap = dso__kernel(dso) ? map__kmap(map) : NULL;
 	struct maps *kmaps = kmap ? map__kmaps(map) : NULL;
-	struct map *curr_map = map;
-	struct dso *curr_dso = dso;
+	struct dso *curr_dso;
 	Elf_Data *symstrs, *secstrs, *secstrs_run, *secstrs_sym;
 	uint32_t nr_syms;
 	int err = -1;
@@ -1586,6 +1579,7 @@ dso__load_sym_internal(struct dso *dso, struct map *map, struct symsrc *syms_ss,
 		remap_kernel = true;
 		adjust_kernel_syms = dso__adjust_symbols(dso);
 	}
+	curr_dso = dso__get(dso);
 	elf_symtab__for_each_symbol(syms, nr_syms, idx, sym) {
 		struct symbol *f;
 		const char *elf_name = elf_sym__name(&sym, symstrs);
@@ -1674,8 +1668,11 @@ dso__load_sym_internal(struct dso *dso, struct map *map, struct symsrc *syms_ss,
 			--sym.st_value;
 
 		if (dso__kernel(dso)) {
-			if (dso__process_kernel_symbol(dso, map, &sym, &shdr, kmaps, kmap, &curr_dso, &curr_map,
-						       section_name, adjust_kernel_syms, kmodule, &remap_kernel))
+			if (dso__process_kernel_symbol(dso, map, &sym, &shdr,
+						       kmaps, kmap, &curr_dso,
+						       section_name,
+						       adjust_kernel_syms,
+						       kmodule, &remap_kernel))
 				goto out_elf_end;
 		} else if ((used_opd && runtime_ss->adjust_symbols) ||
 			   (!used_opd && syms_ss->adjust_symbols)) {
@@ -1724,6 +1721,7 @@ dso__load_sym_internal(struct dso *dso, struct map *map, struct symsrc *syms_ss,
 		__symbols__insert(dso__symbols(curr_dso), f, dso__kernel(dso));
 		nr++;
 	}
+	dso__put(curr_dso);
 
 	/*
 	 * For misannotated, zeroed, ASM function sizes.
-- 
2.43.0.rc2.451.g8631bc7472-goog