On 06/14/2013 03:59 AM, Rafael J. Wysocki wrote: > On Friday, June 14, 2013 12:32:25 AM Jiang Liu wrote: >> 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. > > So my question is, did we have this problem before commit 3b63aaa70e1? > > If we did, then when did it start? Or was it present forever? I think this issue should exist before commit "PCI: acpiphp: Do not use ACPI PCI subdriver mechanism". It may trace back to the changes to kill acpi_pci_bind()/acpi_pci_unbind(). > >> 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. > > Would not the solution be to modify it so that it didn't spawn the other > task (T2), but removed the affected physical devices synchronously? Yes, that's the way I'm going to fix this issue. > >> 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 ACPI glue logic's expection because ACPI devices are destroyed >> in step 3 and physical devices are destroyed in step 5. >> >> Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxx> >> Reported-by: Alexander E. Patrakov <patrakov@xxxxxxxxx> >> Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> >> Cc: Yinghai Lu <yinghai@xxxxxxxxxx> >> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@xxxxxxxxx> >> Cc: linux-pci@xxxxxxxxxxxxxxx >> Cc: linux-kernel@xxxxxxxxxxxxxxx >> Cc: stable@xxxxxxxxxxxxxxx >> --- >> Hi Bjorn and Rafael, >> The recursive lock changes haven't been tested yet, need help >> from Alexander for testing. > > Well, let's just say I'm not a fan of recursive locks. Is that unavoidable > here? Yeah, you are right, we encounter other deadlock issue here, as reported by Alexander. So need to find new solution here. > > Rafael > > >> --- >> drivers/acpi/dock.c | 33 +++++++++++++++++++++++++++------ >> drivers/pci/hotplug/acpiphp_glue.c | 32 ++++++++++++++++++-------------- >> 2 files changed, 45 insertions(+), 20 deletions(-) >> >> diff --git a/drivers/acpi/dock.c b/drivers/acpi/dock.c >> index 02b0563..79c8d9e 100644 >> --- a/drivers/acpi/dock.c >> +++ b/drivers/acpi/dock.c >> @@ -65,6 +65,7 @@ struct dock_station { >> u32 flags; >> spinlock_t dd_lock; >> struct mutex hp_lock; >> + struct task_struct *owner; >> struct list_head dependent_devices; >> struct list_head hotplug_devices; >> >> @@ -131,9 +132,13 @@ static void >> dock_add_hotplug_device(struct dock_station *ds, >> struct dock_dependent_device *dd) >> { >> - mutex_lock(&ds->hp_lock); >> - list_add_tail(&dd->hotplug_list, &ds->hotplug_devices); >> - mutex_unlock(&ds->hp_lock); >> + if (mutex_is_locked(&ds->hp_lock) && ds->owner == current) { >> + list_add_tail(&dd->hotplug_list, &ds->hotplug_devices); >> + } else { >> + mutex_lock(&ds->hp_lock); >> + list_add_tail(&dd->hotplug_list, &ds->hotplug_devices); >> + mutex_unlock(&ds->hp_lock); >> + } >> } >> >> /** >> @@ -147,9 +152,13 @@ static void >> dock_del_hotplug_device(struct dock_station *ds, >> struct dock_dependent_device *dd) >> { >> - mutex_lock(&ds->hp_lock); >> - list_del(&dd->hotplug_list); >> - mutex_unlock(&ds->hp_lock); >> + if (mutex_is_locked(&ds->hp_lock) && ds->owner == current) { >> + list_del_init(&dd->hotplug_list); >> + } else { >> + mutex_lock(&ds->hp_lock); >> + list_del_init(&dd->hotplug_list); >> + mutex_unlock(&ds->hp_lock); >> + } >> } >> >> /** >> @@ -355,7 +364,17 @@ static void hotplug_dock_devices(struct dock_station *ds, u32 event) >> { >> struct dock_dependent_device *dd; >> >> + /* >> + * There is a deadlock scenario as below: >> + * hotplug_dock_devices() >> + * mutex_lock(&ds->hp_lock) >> + * dd->ops->handler() >> + * register_hotplug_dock_device() >> + * mutex_lock(&ds->hp_lock) >> + * So we need recursive lock scematics here, do it by ourselves. >> + */ >> mutex_lock(&ds->hp_lock); >> + ds->owner = current; >> >> /* >> * First call driver specific hotplug functions >> @@ -376,6 +395,8 @@ static void hotplug_dock_devices(struct dock_station *ds, u32 event) >> else >> dock_create_acpi_device(dd->handle); >> } >> + >> + ds->owner = NULL; >> mutex_unlock(&ds->hp_lock); >> } >> >> diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c >> index 716aa93..699b8ca 100644 >> --- a/drivers/pci/hotplug/acpiphp_glue.c >> +++ b/drivers/pci/hotplug/acpiphp_glue.c >> @@ -61,6 +61,8 @@ 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 free_bridge(struct kref *kref); >> >> @@ -147,7 +149,7 @@ 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 */ >> @@ -1065,22 +1067,13 @@ 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(); >> >> acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer); >> >> @@ -1113,7 +1106,18 @@ static void _handle_hotplug_event_func(struct work_struct *work) >> warn("notify_handler: unknown event type 0x%x for %s\n", type, objname); >> break; >> } >> +} >> + >> +static void _handle_hotplug_event_cb(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; >> + 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); >> @@ -1141,7 +1145,7 @@ static void handle_hotplug_event_func(acpi_handle handle, u32 type, >> * don't deadlock on hotplug actions. >> */ >> get_bridge(func->slot->bridge); >> - alloc_acpi_hp_work(handle, type, context, _handle_hotplug_event_func); >> + alloc_acpi_hp_work(handle, type, context, _handle_hotplug_event_cb); >> } >> >> /* >> -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
