Messages in this thread | | | From | "Rafael J. Wysocki" <> | Subject | Re: [PATCH] cpuidle: Check for dev before deregistering it. | Date | Tue, 03 Dec 2013 22:33:08 +0100 |
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On Tuesday, December 03, 2013 10:59:58 AM Konrad Rzeszutek Wilk wrote: > If not, we could end up in the unfortunate situation where > we dereference a NULL pointer b/c we have cpuidle disabled. > > This is the case when booting under Xen (which uses the > ACPI P/C states but disables the CPU idle driver) - and can > be easily reproduced when booting with cpuidle.off=1. > > BUG: unable to handle kernel NULL pointer dereference at (null) > IP: [<ffffffff8156db4a>] cpuidle_unregister_device+0x2a/0x90 > .. snip.. > Call Trace: > [<ffffffff813b15b4>] acpi_processor_power_exit+0x3c/0x5c > [<ffffffff813af0a9>] acpi_processor_stop+0x61/0xb6 > [<ffffffff814215bf>] __device_release_driver+0fffff81421653>] device_release_driver+0x23/0x30 > [<ffffffff81420ed8>] bus_remove_device+0x108/0x180 > [<ffffffff8141d9d9>] device_del+0x129/0x1c0 > [<ffffffff813cb4b0>] ? unregister_xenbus_watch+0x1f0/0x1f0 > [<ffffffff8141da8e>] device_unregister+0x1e/0x60 > [<ffffffff814243e9>] unregister_cpu+0x39/0x60 > [<ffffffff81019e03>] arch_unregister_cpu+0x23/0x30 > [<ffffffff813c3c51>] handle_vcpu_hotplug_event+0xc1/0xe0 > [<ffffffff813cb4f5>] xenwatch_thread+0x45/0x120 > [<ffffffff810af010>] ? abort_exclusive_wait+0xb0/0xb0 > [<ffffffff8108ec42>] kthread+0xd2/0xf0 > [<ffffffff8108eb70>] ? kthread_create_on_node+0x180/0x180 > [<ffffffff816ce17c>] ret_from_fork+0x7c/0xb0 > [<ffffffff8108eb70>] ? kthread_create_on_node+0x180/0x180 > > This problem also appears in 3.12 and could be a candidate for backport. > > CC: "Rafael J. Wysocki" <rjw@rjwysocki.net> > CC: Daniel Lezcano <daniel.lezcano@linaro.org> > CC: linux-pm@vger.kernel.org > Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Applied, thanks!
> --- > drivers/cpuidle/cpuidle.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c > index 2a991e4..a55e68f 100644 > --- a/drivers/cpuidle/cpuidle.c > +++ b/drivers/cpuidle/cpuidle.c > @@ -400,7 +400,7 @@ EXPORT_SYMBOL_GPL(cpuidle_register_device); > */ > void cpuidle_unregister_device(struct cpuidle_device *dev) > { > - if (dev->registered == 0) > + if (!dev || dev->registered == 0) > return; > > cpuidle_pause_and_lock(); > -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.
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