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Subsystems that want to register CPU hotplug callbacks, as well as perform initialization for the CPUs that are already online, often do it as shown below: get_online_cpus(); for_each_online_cpu(cpu) init_cpu(cpu); register_cpu_notifier(&foobar_cpu_notifier); put_online_cpus(); This is wrong, since it is prone to ABBA deadlocks involving the cpu_add_remove_lock and the cpu_hotplug.lock (when running concurrently with CPU hotplug operations). Instead, the correct and race-free way of performing the callback registration is: cpu_notifier_register_begin(); for_each_online_cpu(cpu) init_cpu(cpu); /* Note the use of the double underscored version of the API */ __register_cpu_notifier(&foobar_cpu_notifier); cpu_notifier_register_done(); Fix the nmi-timer code in oprofile by using this latter form of callback registration. Cc: Robert Richter <rric@kernel.org> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> |
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| .. | ||
| buffer_sync.c | ||
| buffer_sync.h | ||
| cpu_buffer.c | ||
| cpu_buffer.h | ||
| event_buffer.c | ||
| event_buffer.h | ||
| nmi_timer_int.c | ||
| oprof.c | ||
| oprof.h | ||
| oprofile_files.c | ||
| oprofile_perf.c | ||
| oprofile_stats.c | ||
| oprofile_stats.h | ||
| oprofilefs.c | ||
| timer_int.c | ||