mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-15 15:15:47 +00:00
fc800a10be
synthetic event is using synth_event_mutex for protecting synth_event_list, and event_trigger_write() path acquires locks as below order. event_trigger_write(event_mutex) ->trigger_process_regex(trigger_cmd_mutex) ->event_hist_trigger_func(synth_event_mutex) On the other hand, synthetic event creation and deletion paths call trace_add_event_call() and trace_remove_event_call() which acquires event_mutex. In that case, if we keep the synth_event_mutex locked while registering/unregistering synthetic events, its dependency will be inversed. To avoid this issue, current synthetic event is using a 2 phase process to create/delete events. For example, it searches existing events under synth_event_mutex to check for event-name conflicts, and unlocks synth_event_mutex, then registers a new event under event_mutex locked. Finally, it locks synth_event_mutex and tries to add the new event to the list. But it can introduce complexity and a chance for name conflicts. To solve this simpler, this introduces trace_add_event_call_nolock() and trace_remove_event_call_nolock() which don't acquire event_mutex inside. synthetic event can lock event_mutex before synth_event_mutex to solve the lock dependency issue simpler. Link: http://lkml.kernel.org/r/154140844377.17322.13781091165954002713.stgit@devbox Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com> Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> |
||
---|---|---|
.. | ||
blktrace.c | ||
bpf_trace.c | ||
fgraph.c | ||
ftrace.c | ||
ftrace_internal.h | ||
Kconfig | ||
Makefile | ||
power-traces.c | ||
preemptirq_delay_test.c | ||
ring_buffer.c | ||
ring_buffer_benchmark.c | ||
rpm-traces.c | ||
trace.c | ||
trace.h | ||
trace_benchmark.c | ||
trace_benchmark.h | ||
trace_branch.c | ||
trace_clock.c | ||
trace_entries.h | ||
trace_event_perf.c | ||
trace_events.c | ||
trace_events_filter.c | ||
trace_events_filter_test.h | ||
trace_events_hist.c | ||
trace_events_trigger.c | ||
trace_export.c | ||
trace_functions.c | ||
trace_functions_graph.c | ||
trace_hwlat.c | ||
trace_irqsoff.c | ||
trace_kdb.c | ||
trace_kprobe.c | ||
trace_kprobe_selftest.c | ||
trace_kprobe_selftest.h | ||
trace_mmiotrace.c | ||
trace_nop.c | ||
trace_output.c | ||
trace_output.h | ||
trace_preemptirq.c | ||
trace_printk.c | ||
trace_probe.c | ||
trace_probe.h | ||
trace_probe_tmpl.h | ||
trace_sched_switch.c | ||
trace_sched_wakeup.c | ||
trace_selftest.c | ||
trace_selftest_dynamic.c | ||
trace_seq.c | ||
trace_stack.c | ||
trace_stat.c | ||
trace_stat.h | ||
trace_syscalls.c | ||
trace_uprobe.c | ||
tracing_map.c | ||
tracing_map.h |