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author | Silas Boyd-Wickizer <sbw@mit.edu> | 2012-08-03 12:33:27 -0700 |
---|---|---|
committer | Viresh Kumar <viresh.kumar@linaro.org> | 2012-10-03 15:21:58 +0530 |
commit | 6be308bec37393da5f3f81616bbeccb910c6d9a4 (patch) | |
tree | 21869ba864ee1932efdff7d639add19223bebd3a /drivers/infiniband/hw/ehca/ehca_irq.c | |
parent | 44440fae749868b6d38ccf19966c8da5a4d73ebc (diff) |
Use get_online_cpus to avoid races involving CPU hotplug
If arch/x86/kernel/msr.c is a module, a CPU might offline or online
between the for_each_online_cpu(i) loop and the call to
register_hotcpu_notifier in msr_init or the call to
unregister_hotcpu_notifier in msr_exit. The potential races can lead
to leaks/duplicates, attempts to destroy non-existant devices, or
random pointer dereferences.
For example, in msr_init if:
for_each_online_cpu(i) {
err = msr_device_create(i);
if (err != 0)
goto out_class;
}
<----- CPU offlines
register_hotcpu_notifier(&msr_class_cpu_notifier);
and the CPU never onlines before msr_exit, then the module will never
call msr_device_destroy for the associated CPU.
This fix surrounds for_each_online_cpu and register_hotcpu_notifier or
unregister_hotcpu_notifier with get_online_cpus+put_online_cpus.
Tested on a VM.
Signed-off-by: Silas Boyd-Wickizer <sbw@mit.edu>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'drivers/infiniband/hw/ehca/ehca_irq.c')
0 files changed, 0 insertions, 0 deletions