From 5e78c69b72276853ac64070a010e6df64723dba9 Mon Sep 17 00:00:00 2001 From: He Kuang Date: Fri, 10 Apr 2015 17:35:00 +0800 Subject: [PATCH] perf buildid-list: Fix segfault when show DSOs with hits commit: f3b623b8490a ("perf tools: Reference count struct thread") appends every thread->node to dead_threads in machine__remove_thread() and list_del_init() this node in thread__put(). perf_event__exit_del_thread() releases thread wihout using machine__remove_thread(), and causes a NULL pointer crash when list_del_init(&thread->node) is called. Fix this by using machine_remove_thread() instead of using thread__put() directly. This problem can be reproduced as following: $ perf record ls $ perf buildid-list --with-hits [ 3874.195070] perf[1018]: segfault at 0 ip 00000000004b0b15 sp 00007ffc35b44780 error 6 in perf[400000+166000] Segmentation fault After this patch: $ perf record ls $ perf buildid-list --with-hits bc23e7c3281e542650ba4324421d6acf78f4c23e /proc/kcore 643324cb0e969f30c56d660f167f84a150845511 [vdso] 0000000000000000000000000000000000000000 /bin/busybox ... Signed-off-by: He Kuang Tested-by: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Wang Nan Link: http://lkml.kernel.org/r/1428658500-6483-1-git-send-email-hekuang@huawei.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/build-id.c | 8 ++------ tools/perf/util/machine.c | 4 +--- tools/perf/util/machine.h | 1 + 3 files changed, 4 insertions(+), 9 deletions(-) diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c index f7fb258..61867df 100644 --- a/tools/perf/util/build-id.c +++ b/tools/perf/util/build-id.c @@ -59,12 +59,8 @@ static int perf_event__exit_del_thread(struct perf_tool *tool __maybe_unused, dump_printf("(%d:%d):(%d:%d)\n", event->fork.pid, event->fork.tid, event->fork.ppid, event->fork.ptid); - if (thread) { - rb_erase(&thread->rb_node, &machine->threads); - if (machine->last_match == thread) - thread__zput(machine->last_match); - thread__put(thread); - } + if (thread) + machine__remove_thread(machine, thread); return 0; } diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c index 9c380a2..527e032 100644 --- a/tools/perf/util/machine.c +++ b/tools/perf/util/machine.c @@ -14,8 +14,6 @@ #include "unwind.h" #include "linux/hash.h" -static void machine__remove_thread(struct machine *machine, struct thread *th); - static void dsos__init(struct dsos *dsos) { INIT_LIST_HEAD(&dsos->head); @@ -1256,7 +1254,7 @@ out_problem: return 0; } -static void machine__remove_thread(struct machine *machine, struct thread *th) +void machine__remove_thread(struct machine *machine, struct thread *th) { if (machine->last_match == th) thread__zput(machine->last_match); diff --git a/tools/perf/util/machine.h b/tools/perf/util/machine.h index e2faf3b..6d64ced 100644 --- a/tools/perf/util/machine.h +++ b/tools/perf/util/machine.h @@ -120,6 +120,7 @@ int machine__init(struct machine *machine, const char *root_dir, pid_t pid); void machine__exit(struct machine *machine); void machine__delete_threads(struct machine *machine); void machine__delete(struct machine *machine); +void machine__remove_thread(struct machine *machine, struct thread *th); struct branch_info *sample__resolve_bstack(struct perf_sample *sample, struct addr_location *al); -- 2.7.4