@@ -269,12 +269,17 @@ err_inject_init(void)
#ifdef ERR_INJ_DEBUG
printk(KERN_INFO "Enter error injection driver.\n");
#endif
+
+ cpu_notifier_register_begin();
+
for_each_online_cpu(i) {
err_inject_cpu_callback(&err_inject_cpu_notifier, CPU_ONLINE,
(void *)(long)i);
}
- register_hotcpu_notifier(&err_inject_cpu_notifier);
+ __register_hotcpu_notifier(&err_inject_cpu_notifier);
+
+ cpu_notifier_register_done();
return 0;
}
@@ -288,11 +293,17 @@ err_inject_exit(void)
#ifdef ERR_INJ_DEBUG
printk(KERN_INFO "Exit error injection driver.\n");
#endif
+
+ cpu_notifier_register_begin();
+
for_each_online_cpu(i) {
sys_dev = get_cpu_device(i);
sysfs_remove_group(&sys_dev->kobj, &err_inject_attr_group);
}
- unregister_hotcpu_notifier(&err_inject_cpu_notifier);
+
+ __unregister_hotcpu_notifier(&err_inject_cpu_notifier);
+
+ cpu_notifier_register_done();
}
module_init(err_inject_init);
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 error injection code in ia64 by using this latter form of callback registration. Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: linux-ia64@vger.kernel.org Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> --- arch/ia64/kernel/err_inject.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html