Messages in this thread Patch in this message | | | Date | Wed, 29 Dec 2021 16:55:19 +0800 | From | yaowenbin <> | Subject | [PATCH] perf top: add concurrent access protection of the SLsmg screen management |
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When the following command is executed several times, a coredump file is generated. $ timeout -k 9 5 perf top -e task-clock ******* ******* ******* 0.01% [kernel] [k] __do_softirq 0.01% libpthread-2.28.so [.] __pthread_mutex_lock 0.01% [kernel] [k] __ll_sc_atomic64_sub_return double free or corruption (!prev) perf top --sort comm,dso timeout: the monitored command dumped core
When we terminate "perf top" using sending signal method, SLsmg_reset_smg function is called. SLsmg_reset_smg resets the SLsmg screen management routines by freeing all memory allocated while it was active. However SLsmg_reinit_smg function maybe be called by another thread. SLsmg_reinit_smg function will free the same memory accessed by SLsmg_reset_smg functon, thus it results in double free. SLsmg_reinit_smg function is called already protected by ui__lock, so we fix the problem by adding pthread_mutex_trylock of ui__lock when calling SLsmg_reset_smg function.
Signed-off-by: yaowenbin <yaowenbin1@huawei.com> Signed-off-by: hewenliang <hewenliang4@huawei.com> Signed-off-by: Wenyu Liu <liuwenyu7@huawei.com> --- tools/perf/ui/tui/setup.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/tools/perf/ui/tui/setup.c b/tools/perf/ui/tui/setup.c index d4ac41679..1fdf92062 100644 --- a/tools/perf/ui/tui/setup.c +++ b/tools/perf/ui/tui/setup.c @@ -170,9 +170,11 @@ void ui__exit(bool wait_for_ok) "Press any key...", 0);
SLtt_set_cursor_visibility(1); - SLsmg_refresh(); - SLsmg_reset_smg(); + if (!pthread_mutex_trylock(&ui__lock)) { + SLsmg_refresh(); + SLsmg_reset_smg(); + pthread_mutex_unlock(&ui__lock); + } SLang_reset_tty(); - perf_error__unregister(&perf_tui_eops); } -- 2.27.0
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