From 566c69c36e6178774dd484ea4a02b76f6bd0ede4 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Wed, 18 Nov 2015 15:40:35 +0900 Subject: [PATCH] perf machine: Fix machine__findnew_module_map to put dso Fix machine__findnew_module_map to drop the reference to the dso because it is already referenced by both machine__findnew_module_dso() and map__new2(). Refcnt debugger shows: ==== [1] ==== Unreclaimed dso: 0x1ffd980 Refcount +1 => 1 at ./perf(dso__new+0x1ff) [0x4a62df] ./perf(__dsos__addnew+0x29) [0x4a6e19] ./perf() [0x4b8b91] ./perf(modules__parse+0xfc) [0x4a9d5c] ./perf() [0x4b8460] ./perf(machine__create_kernel_maps+0x150) [0x4bb550] ./perf(machine__new_host+0xfa) [0x4bb75a] ./perf(init_probe_symbol_maps+0x93) [0x506623] ./perf() [0x455ffa] ./perf(cmd_probe+0x6c) [0x4566bc] ./perf() [0x47abc5] ./perf(main+0x610) [0x421f90] /lib64/libc.so.6(__libc_start_main+0xf5) [0x7f1345a8eaf5] ./perf() [0x4220a9] This map_groups__insert(0x4b8b91) already gets a reference to the new dso: ---- eu-addr2line -e ./perf -f 0x4b8b91 map_groups__insert inlined at util/machine.c:586 in machine__create_module util/map.h:207 ---- So this dso refcnt will be released when map_groups gets released. [snip] Refcount +1 => 2 at ./perf(dso__get+0x34) [0x4a65f4] ./perf() [0x4b8b35] ./perf(modules__parse+0xfc) [0x4a9d5c] ./perf() [0x4b8460] ./perf(machine__create_kernel_maps+0x150) [0x4bb550] ./perf(machine__new_host+0xfa) [0x4bb75a] ./perf(init_probe_symbol_maps+0x93) [0x506623] ./perf() [0x455ffa] ./perf(cmd_probe+0x6c) [0x4566bc] ./perf() [0x47abc5] ./perf(main+0x610) [0x421f90] /lib64/libc.so.6(__libc_start_main+0xf5) [0x7f1345a8eaf5] ./perf() [0x4220a9] Here, machine__findnew_module_dso(0x4b8b35) gets the dso (and stores it in a local variable): ---- # eu-addr2line -e ./perf -f 0x4b8b35 machine__findnew_module_dso inlined at util/machine.c:578 in machine__create_module util/machine.c:514 ---- Refcount +1 => 3 at ./perf(dso__get+0x34) [0x4a65f4] ./perf(map__new2+0x76) [0x4be1c6] ./perf() [0x4b8b4f] ./perf(modules__parse+0xfc) [0x4a9d5c] ./perf() [0x4b8460] ./perf(machine__create_kernel_maps+0x150) [0x4bb550] ./perf(machine__new_host+0xfa) [0x4bb75a] ./perf(init_probe_symbol_maps+0x93) [0x506623] ./perf() [0x455ffa] ./perf(cmd_probe+0x6c) [0x4566bc] ./perf() [0x47abc5] ./perf(main+0x610) [0x421f90] /lib64/libc.so.6(__libc_start_main+0xf5) [0x7f1345a8eaf5] ./perf() [0x4220a9] But also map__new2() gets the dso which will be put when the map is released. So, we have to drop the constructor reference obtained in machine__findnew_module_dso(). Signed-off-by: Masami Hiramatsu Cc: Adrian Hunter Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20151118064035.30709.58824.stgit@localhost.localdomain Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/machine.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c index 0b4a05c14204..7f5071a4d9aa 100644 --- a/tools/perf/util/machine.c +++ b/tools/perf/util/machine.c @@ -565,7 +565,7 @@ struct map *machine__findnew_module_map(struct machine *machine, u64 start, const char *filename) { struct map *map = NULL; - struct dso *dso; + struct dso *dso = NULL; struct kmod_path m; if (kmod_path__parse_name(&m, filename)) @@ -589,6 +589,8 @@ struct map *machine__findnew_module_map(struct machine *machine, u64 start, /* Put the map here because map_groups__insert alread got it */ map__put(map); out: + /* put the dso here, corresponding to machine__findnew_module_dso */ + dso__put(dso); free(m.name); return map; } -- 2.20.1