Messages in this thread |  | | Date | Mon, 4 Nov 2013 15:35:17 +0100 | From | Oleg Nesterov <> | Subject | Re: [PATCH 10/13] tracing/uprobes: Fetch args before reserving a ring buffer |
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Hi Namhyung,
On 11/04, Namhyung Kim wrote: > > >> > >> + if (atomic_dec_and_test(&uprobe_buffer_ref)) { > >> + free_percpu(uprobe_cpu_buffer); > >> + uprobe_cpu_buffer = NULL; > >> + } > >> + > >> WARN_ON(!uprobe_filter_is_empty(&tu->filter)); > > > > Do we really need atomic_t? probe_event_enable/disable is called under > > event_mutex and we rely on this fact anyway. > > Looking at the code, it seems probe_event_enable/disable() is called > without event_mutex when it called from sys_perf_event_open().
Where?
__ftrace_set_clr_event(), perf_trace_init() or perf_trace_destroy() hold event_mutex. We rely on this fact anyway.
Oleg.
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