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? > 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? > 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? 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); > } > > /* > -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- 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
