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Date: Tue, 11 Jun 2013 20:24:46 +0800
From: Jiang Liu <liuj97@...il.com>
To: "Alexander E. Patrakov" <patrakov@...il.com>
CC: Jiang Liu <jiang.liu@...wei.com>,
Bjorn Helgaas <bhelgaas@...gle.com>,
Yinghai Lu <yinghai@...nel.org>,
"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
linux-pci@...r.kernel.org,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] ACPIPHP: fix device destroying order issue in handling
dock notification
On Tue 11 Jun 2013 08:15:11 PM CST, Alexander E. Patrakov wrote:
> 2013/6/11 Jiang Liu <liuj97@...il.com>:
>> Current ACPI glue logic expects that physical devices are destroyed
>> before destroying companion ACPI devices, otherwise it will break the
>> ACPI unbind logic and cause following warning messages:
>> [ 185.026073] usb usb5: Oops, 'acpi_handle' corrupt
>> [ 185.035150] pci 0000:1b:00.0: Oops, 'acpi_handle' corrupt
>> [ 185.035515] pci 0000:18:02.0: Oops, 'acpi_handle' corrupt
>> [ 180.013656] port1: Oops, 'acpi_handle' corrupt
>> Please refer to https://bugzilla.kernel.org/attachment.cgi?id=104321
>> for full log message.
>
> This causes lockdep spew, see
> https://bugzilla.kernel.org/attachment.cgi?id=104411
>
> So, probably a NAK.
>
>> Above warning messages are caused by following scenario:
>> 1) acpi_dock_notifier_call() queues a task (T1) onto kacpi_hotplug_wq
>> 2) kacpi_hotplug_wq handles T1, which invokes acpi_dock_deferred_cb()
>> ->dock_notify()-> handle_eject_request()->hotplug_dock_devices()
>> 3) hotplug_dock_devices() first invokes registered hotplug callbacks to
>> destroy physical devices, then destroys all affected ACPI devices.
>> Everything seems perfect until now. But the acpiphp dock notification
>> handler will queue another task (T2) onto kacpi_hotplug_wq to really
>> destroy affected physical devices.
>> 4) kacpi_hotplug_wq finishes T1, and all affected ACPI devices have
>> been destroyed.
>> 5) kacpi_hotplug_wq handles T2, which destroys all affected physical
>> devices.
>>
>> So it breaks the ACPI glue expection because ACPI devices are destroyed
>> in step 3 and physical devices are destroyed in step 5.
>>
>> Signed-off-by: Jiang Liu <jiang.liu@...wei.com>
>> Cc: Bjorn Helgaas <bhelgaas@...gle.com>
>> Cc: Yinghai Lu <yinghai@...nel.org>
>> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>
>> Cc: linux-pci@...r.kernel.org
>> Cc: linux-kernel@...r.kernel.org
>> ---
>> Hi all,
>> We are trying to solve bug https://bugzilla.kernel.org/show_bug.cgi?id=59501
>> And seems there are multiple bugs behind bug 59501. This draft patch tries to
>> fix one of those issues. I will send out form patchset once all issue have been
>> resolved.
>>
>> Regards!
>> Gerry
>> ---
>> drivers/pci/hotplug/acpiphp_glue.c | 31 +++++++++++++++++++------------
>> 1 file changed, 19 insertions(+), 12 deletions(-)
>>
>> diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
>> index 716aa93..b132aca 100644
>> --- a/drivers/pci/hotplug/acpiphp_glue.c
>> +++ b/drivers/pci/hotplug/acpiphp_glue.c
>> @@ -61,7 +61,10 @@ static DEFINE_MUTEX(bridge_mutex);
>> static void handle_hotplug_event_bridge (acpi_handle, u32, void *);
>> static void acpiphp_sanitize_bus(struct pci_bus *bus);
>> static void acpiphp_set_hpp_values(struct pci_bus *bus);
>> -static void handle_hotplug_event_func(acpi_handle handle, u32 type, void *context);
>> +static void __handle_hotplug_event_func(acpi_handle handle, u32 type,
>> + void *context);
>> +static void handle_hotplug_event_func(acpi_handle handle, u32 type,
>> + void *context);
>> static void free_bridge(struct kref *kref);
>>
>> /* callback routine to check for the existence of a pci dock device */
>> @@ -147,7 +150,7 @@ static int post_dock_fixups(struct notifier_block *nb, unsigned long val,
>>
>>
>> static const struct acpi_dock_ops acpiphp_dock_ops = {
>> - .handler = handle_hotplug_event_func,
>> + .handler = __handle_hotplug_event_func,
>> };
>>
>> /* Check whether the PCI device is managed by native PCIe hotplug driver */
>> @@ -1065,20 +1068,13 @@ static void handle_hotplug_event_bridge(acpi_handle handle, u32 type,
>> alloc_acpi_hp_work(handle, type, context, _handle_hotplug_event_bridge);
>> }
>>
>> -static void _handle_hotplug_event_func(struct work_struct *work)
>> +static void __handle_hotplug_event_func(acpi_handle handle, u32 type,
>> + void *context)
>> {
>> - struct acpiphp_func *func;
>> + struct acpiphp_func *func = context;
>> char objname[64];
>> struct acpi_buffer buffer = { .length = sizeof(objname),
>> .pointer = objname };
>> - struct acpi_hp_work *hp_work;
>> - acpi_handle handle;
>> - u32 type;
>> -
>> - hp_work = container_of(work, struct acpi_hp_work, work);
>> - handle = hp_work->handle;
>> - type = hp_work->type;
>> - func = (struct acpiphp_func *)hp_work->context;
>>
>> acpi_scan_lock_acquire();
>>
>> @@ -1115,6 +1111,17 @@ static void _handle_hotplug_event_func(struct work_struct *work)
>> }
>>
>> acpi_scan_lock_release();
>> +}
>> +
>> +static void _handle_hotplug_event_func(struct work_struct *work)
>> +{
>> + struct acpiphp_func *func;
>> + struct acpi_hp_work *hp_work;
>> +
>> + hp_work = container_of(work, struct acpi_hp_work, work);
>> + func = (struct acpiphp_func *)hp_work->context;
>> + __handle_hotplug_event_func(hp_work->handle, hp_work->type,
>> + hp_work->context);
>> kfree(hp_work); /* allocated in handle_hotplug_event_func */
>> put_bridge(func->slot->bridge);
>> }
>> --
>> 1.8.1.2
>>
>
>
>
> --
> Alexander E. Patrakov
Hi Alexander,
Sorry for the deadlock, I have no machine for testing:(
Below patch should fix the deadlock issue.
Regards!
----
diff --git a/drivers/pci/hotplug/acpiphp_glue.c
b/drivers/pci/hotplug/acpiphp_glue.c
index 0302645..699b8ca 100644
--- a/drivers/pci/hotplug/acpiphp_glue.c
+++ b/drivers/pci/hotplug/acpiphp_glue.c
@@ -1075,8 +1075,6 @@ static void
_handle_hotplug_event_func(acpi_handle handle, u32 type,
struct acpi_buffer buffer = { .length = sizeof(objname),
.pointer = objname };
- acpi_scan_lock_acquire();
-
acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
switch (type) {
@@ -1108,8 +1106,6 @@ static void
_handle_hotplug_event_func(acpi_handle handle, u32 type,
warn("notify_handler: unknown event type 0x%x for
%s\n", type, objname);
break;
}
-
- acpi_scan_lock_release();
}
static void _handle_hotplug_event_cb(struct work_struct *work)
@@ -1119,8 +1115,10 @@ static void _handle_hotplug_event_cb(struct
work_struct *work)
hp_work = container_of(work, struct acpi_hp_work, work);
func = (struct acpiphp_func *)hp_work->context;
+ acpi_scan_lock_acquire();
_handle_hotplug_event_func(hp_work->handle, hp_work->type,
hp_work->context);
+ acpi_scan_lock_release();
kfree(hp_work); /* allocated in handle_hotplug_event_func */
put_bridge(func->slot->bridge);
}
--
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