Hi Ishimatsu-san:
By the way, if you want to reproduce this problem, just
modify my patch1 to call __container_notify_cb() directly
in container_notify_cb(). And apply my patch2.
Then, you add a container, and remove it.
The deadlock will be triggered.
And this patch is based on Lu Yinghai's tree:
git://git.kernel.org/pub/scm/linux/kernel/git/yinghai/linux-yinghai.git
for-pci-split-pci-root-hp-2
On 10/24/2012 02:54 PM, Yasuaki Ishimatsu wrote:
> Hi Tang,
>
> 2012/10/24 15:05, Tang Chen wrote:
>> As the comments in __acpi_os_execute() said:
>>
>> We can't run hotplug code in keventd_wq/kacpid_wq/kacpid_notify_wq
>> because the hotplug code may call driver .remove() functions,
>> which invoke flush_scheduled_work/acpi_os_wait_events_complete
>> to flush these workqueues.
>>
>> we should keep the hotplug code in kacpi_hotplug_wq.
>>
>> But we have the following call series in kernel now:
>> acpi_ev_queue_notify_request()
>> |--> acpi_os_execute()
>> |--> __acpi_os_execute(type, function, context, 0)
>>
>> The last parameter 0 makes the container_notify_cb() executed in
>> kacpi_notify_wq or kacpid_wq. So, we need to put the real hotplug code
>> into kacpi_hotplug_wq.
>
> I cannot understand the purpose of the patch.
> Is the patch a bug fix patch? If yes, what problem happens?
>
> Thanks,
> Yasuaki Ishimatsu
>
>>
>> Signed-off-by: Tang Chen<tangchen@xxxxxxxxxxxxxx>
>> ---
>> drivers/acpi/container.c | 17 ++++++++++++++++-
>> 1 files changed, 16 insertions(+), 1 deletions(-)
>>
>> diff --git a/drivers/acpi/container.c b/drivers/acpi/container.c
>> index 69e2d6b..d300e03 100644
>> --- a/drivers/acpi/container.c
>> +++ b/drivers/acpi/container.c
>> @@ -35,6 +35,7 @@
>> #include<acpi/acpi_bus.h>
>> #include<acpi/acpi_drivers.h>
>> #include<acpi/container.h>
>> +#include<acpi/acpiosxf.h>
>>
>> #define PREFIX "ACPI: "
>>
>> @@ -165,14 +166,21 @@ static int container_device_add(struct acpi_device **device, acpi_handle handle)
>> return result;
>> }
>>
>> -static void container_notify_cb(acpi_handle handle, u32 type, void *context)
>> +static void __container_notify_cb(struct work_struct *work)
>> {
>> struct acpi_device *device = NULL;
>> int result;
>> int present;
>> acpi_status status;
>> + struct acpi_hp_work *hp_work;
>> + acpi_handle handle;
>> + u32 type;
>> u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */
>>
>> + hp_work = container_of(work, struct acpi_hp_work, work);
>> + handle = hp_work->handle;
>> + type = hp_work->type;
>> +
>> switch (type) {
>> case ACPI_NOTIFY_BUS_CHECK:
>> /* Fall through */
>> @@ -224,6 +232,13 @@ static void container_notify_cb(acpi_handle handle, u32 type, void *context)
>> return;
>> }
>>
>> +static void container_notify_cb(acpi_handle handle, u32 type,
>> + void *context)
>> +{
>> + alloc_acpi_hp_work(handle, type, context,
>> + __container_notify_cb);
>> +}
>> +
>> static acpi_status
>> container_walk_namespace_cb(acpi_handle handle,
>> u32 lvl, void *context, void **rv)
>>
>
>
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