| Message ID | cf3f7fec1241c22f49cbe8205c2b1129eb4bb3d7.1459950922.git.mchehab@osg.samsung.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 04/06/2016 03:55 PM, Mauro Carvalho Chehab wrote: > Right now, the lock schema for media_device struct is messy, > since sometimes, it is protected via a spin lock, while, for > media graph traversal, it is protected by a mutex. > > Solve this conflict by always using a mutex. > > As a side effect, this prevents a bug when the media notifiers > is called at atomic context, while running the notifier callback: > > BUG: sleeping function called from invalid context at mm/slub.c:1289 > in_atomic(): 1, irqs_disabled(): 0, pid: 3479, name: modprobe > 4 locks held by modprobe/3479: > #0: (&dev->mutex){......}, at: [<ffffffff81ce8933>] __driver_attach+0xa3/0x160 > #1: (&dev->mutex){......}, at: [<ffffffff81ce8941>] __driver_attach+0xb1/0x160 > #2: (register_mutex#5){+.+.+.}, at: [<ffffffffa10596c7>] usb_audio_probe+0x257/0x1c90 [snd_usb_audio] > #3: (&(&mdev->lock)->rlock){+.+.+.}, at: [<ffffffffa0e6051b>] media_device_register_entity+0x1cb/0x700 [media] > CPU: 2 PID: 3479 Comm: modprobe Not tainted 4.5.0-rc3+ #49 > Hardware name: /NUC5i7RYB, BIOS RYBDWi35.86A.0350.2015.0812.1722 08/12/2015 > 0000000000000000 ffff8803b3f6f288 ffffffff81933901 ffff8803c4bae000 > ffff8803c4bae5c8 ffff8803b3f6f2b0 ffffffff811c6af5 ffff8803c4bae000 > ffffffff8285d7f6 0000000000000509 ffff8803b3f6f2f0 ffffffff811c6ce5 > Call Trace: > [<ffffffff81933901>] dump_stack+0x85/0xc4 > [<ffffffff811c6af5>] ___might_sleep+0x245/0x3a0 > [<ffffffff811c6ce5>] __might_sleep+0x95/0x1a0 > [<ffffffff8155aade>] kmem_cache_alloc_trace+0x20e/0x300 > [<ffffffffa0e66e3d>] ? media_add_link+0x4d/0x140 [media] > [<ffffffffa0e66e3d>] media_add_link+0x4d/0x140 [media] > [<ffffffffa0e69931>] media_create_pad_link+0xa1/0x600 [media] > [<ffffffffa0fe11b3>] au0828_media_graph_notify+0x173/0x360 [au0828] > [<ffffffffa0e68a6a>] ? media_gobj_create+0x1ba/0x480 [media] > [<ffffffffa0e606fb>] media_device_register_entity+0x3ab/0x700 [media] > > Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com> > Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> > Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com> Acked-by: Hans Verkuil <hans.verkuil@cisco.com> Regards, Hans > --- > drivers/media/media-device.c | 39 +++++++++++++-------------------------- > drivers/media/media-entity.c | 16 ++++++++-------- > include/media/media-device.h | 6 +----- > 3 files changed, 22 insertions(+), 39 deletions(-) > > diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c > index 6e43c95629ea..898a3cf814ba 100644 > --- a/drivers/media/media-device.c > +++ b/drivers/media/media-device.c > @@ -90,18 +90,13 @@ static struct media_entity *find_entity(struct media_device *mdev, u32 id) > > id &= ~MEDIA_ENT_ID_FLAG_NEXT; > > - spin_lock(&mdev->lock); > - > media_device_for_each_entity(entity, mdev) { > if (((media_entity_id(entity) == id) && !next) || > ((media_entity_id(entity) > id) && next)) { > - spin_unlock(&mdev->lock); > return entity; > } > } > > - spin_unlock(&mdev->lock); > - > return NULL; > } > > @@ -431,6 +426,7 @@ static long media_device_ioctl(struct file *filp, unsigned int cmd, > struct media_device *dev = to_media_device(devnode); > long ret; > > + mutex_lock(&dev->graph_mutex); > switch (cmd) { > case MEDIA_IOC_DEVICE_INFO: > ret = media_device_get_info(dev, > @@ -443,29 +439,24 @@ static long media_device_ioctl(struct file *filp, unsigned int cmd, > break; > > case MEDIA_IOC_ENUM_LINKS: > - mutex_lock(&dev->graph_mutex); > ret = media_device_enum_links(dev, > (struct media_links_enum __user *)arg); > - mutex_unlock(&dev->graph_mutex); > break; > > case MEDIA_IOC_SETUP_LINK: > - mutex_lock(&dev->graph_mutex); > ret = media_device_setup_link(dev, > (struct media_link_desc __user *)arg); > - mutex_unlock(&dev->graph_mutex); > break; > > case MEDIA_IOC_G_TOPOLOGY: > - mutex_lock(&dev->graph_mutex); > ret = media_device_get_topology(dev, > (struct media_v2_topology __user *)arg); > - mutex_unlock(&dev->graph_mutex); > break; > > default: > ret = -ENOIOCTLCMD; > } > + mutex_unlock(&dev->graph_mutex); > > return ret; > } > @@ -590,12 +581,12 @@ int __must_check media_device_register_entity(struct media_device *mdev, > if (!ida_pre_get(&mdev->entity_internal_idx, GFP_KERNEL)) > return -ENOMEM; > > - spin_lock(&mdev->lock); > + mutex_lock(&mdev->graph_mutex); > > ret = ida_get_new_above(&mdev->entity_internal_idx, 1, > &entity->internal_idx); > if (ret < 0) { > - spin_unlock(&mdev->lock); > + mutex_unlock(&mdev->graph_mutex); > return ret; > } > > @@ -615,9 +606,6 @@ int __must_check media_device_register_entity(struct media_device *mdev, > (notify)->notify(entity, notify->notify_data); > } > > - spin_unlock(&mdev->lock); > - > - mutex_lock(&mdev->graph_mutex); > if (mdev->entity_internal_idx_max > >= mdev->pm_count_walk.ent_enum.idx_max) { > struct media_entity_graph new = { .top = 0 }; > @@ -680,9 +668,9 @@ void media_device_unregister_entity(struct media_entity *entity) > if (mdev == NULL) > return; > > - spin_lock(&mdev->lock); > + mutex_lock(&mdev->graph_mutex); > __media_device_unregister_entity(entity); > - spin_unlock(&mdev->lock); > + mutex_unlock(&mdev->graph_mutex); > } > EXPORT_SYMBOL_GPL(media_device_unregister_entity); > > @@ -703,7 +691,6 @@ void media_device_init(struct media_device *mdev) > INIT_LIST_HEAD(&mdev->pads); > INIT_LIST_HEAD(&mdev->links); > INIT_LIST_HEAD(&mdev->entity_notify); > - spin_lock_init(&mdev->lock); > mutex_init(&mdev->graph_mutex); > ida_init(&mdev->entity_internal_idx); > > @@ -752,9 +739,9 @@ EXPORT_SYMBOL_GPL(__media_device_register); > int __must_check media_device_register_entity_notify(struct media_device *mdev, > struct media_entity_notify *nptr) > { > - spin_lock(&mdev->lock); > + mutex_lock(&mdev->graph_mutex); > list_add_tail(&nptr->list, &mdev->entity_notify); > - spin_unlock(&mdev->lock); > + mutex_unlock(&mdev->graph_mutex); > return 0; > } > EXPORT_SYMBOL_GPL(media_device_register_entity_notify); > @@ -771,9 +758,9 @@ static void __media_device_unregister_entity_notify(struct media_device *mdev, > void media_device_unregister_entity_notify(struct media_device *mdev, > struct media_entity_notify *nptr) > { > - spin_lock(&mdev->lock); > + mutex_lock(&mdev->graph_mutex); > __media_device_unregister_entity_notify(mdev, nptr); > - spin_unlock(&mdev->lock); > + mutex_unlock(&mdev->graph_mutex); > } > EXPORT_SYMBOL_GPL(media_device_unregister_entity_notify); > > @@ -787,11 +774,11 @@ void media_device_unregister(struct media_device *mdev) > if (mdev == NULL) > return; > > - spin_lock(&mdev->lock); > + mutex_lock(&mdev->graph_mutex); > > /* Check if mdev was ever registered at all */ > if (!media_devnode_is_registered(&mdev->devnode)) { > - spin_unlock(&mdev->lock); > + mutex_unlock(&mdev->graph_mutex); > return; > } > > @@ -811,7 +798,7 @@ void media_device_unregister(struct media_device *mdev) > kfree(intf); > } > > - spin_unlock(&mdev->lock); > + mutex_unlock(&mdev->graph_mutex); > > device_remove_file(&mdev->devnode.dev, &dev_attr_model); > media_devnode_unregister(&mdev->devnode); > diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c > index e95070b3a3d4..c53c1d5589a0 100644 > --- a/drivers/media/media-entity.c > +++ b/drivers/media/media-entity.c > @@ -219,7 +219,7 @@ int media_entity_pads_init(struct media_entity *entity, u16 num_pads, > entity->pads = pads; > > if (mdev) > - spin_lock(&mdev->lock); > + mutex_lock(&mdev->graph_mutex); > > for (i = 0; i < num_pads; i++) { > pads[i].entity = entity; > @@ -230,7 +230,7 @@ int media_entity_pads_init(struct media_entity *entity, u16 num_pads, > } > > if (mdev) > - spin_unlock(&mdev->lock); > + mutex_unlock(&mdev->graph_mutex); > > return 0; > } > @@ -747,9 +747,9 @@ void media_entity_remove_links(struct media_entity *entity) > if (mdev == NULL) > return; > > - spin_lock(&mdev->lock); > + mutex_lock(&mdev->graph_mutex); > __media_entity_remove_links(entity); > - spin_unlock(&mdev->lock); > + mutex_unlock(&mdev->graph_mutex); > } > EXPORT_SYMBOL_GPL(media_entity_remove_links); > > @@ -951,9 +951,9 @@ void media_remove_intf_link(struct media_link *link) > if (mdev == NULL) > return; > > - spin_lock(&mdev->lock); > + mutex_lock(&mdev->graph_mutex); > __media_remove_intf_link(link); > - spin_unlock(&mdev->lock); > + mutex_unlock(&mdev->graph_mutex); > } > EXPORT_SYMBOL_GPL(media_remove_intf_link); > > @@ -975,8 +975,8 @@ void media_remove_intf_links(struct media_interface *intf) > if (mdev == NULL) > return; > > - spin_lock(&mdev->lock); > + mutex_lock(&mdev->graph_mutex); > __media_remove_intf_links(intf); > - spin_unlock(&mdev->lock); > + mutex_unlock(&mdev->graph_mutex); > } > EXPORT_SYMBOL_GPL(media_remove_intf_links); > diff --git a/include/media/media-device.h b/include/media/media-device.h > index 07809f698464..b21ef244ad3e 100644 > --- a/include/media/media-device.h > +++ b/include/media/media-device.h > @@ -25,7 +25,6 @@ > > #include <linux/list.h> > #include <linux/mutex.h> > -#include <linux/spinlock.h> > > #include <media/media-devnode.h> > #include <media/media-entity.h> > @@ -304,8 +303,7 @@ struct media_entity_notify { > * @pads: List of registered pads > * @links: List of registered links > * @entity_notify: List of registered entity_notify callbacks > - * @lock: Entities list lock > - * @graph_mutex: Entities graph operation lock > + * @graph_mutex: Protects access to struct media_device data > * @pm_count_walk: Graph walk for power state walk. Access serialised using > * graph_mutex. > * > @@ -371,8 +369,6 @@ struct media_device { > /* notify callback list invoked when a new entity is registered */ > struct list_head entity_notify; > > - /* Protects the graph objects creation/removal */ > - spinlock_t lock; > /* Serializes graph operations. */ > struct mutex graph_mutex; > struct media_entity_graph pm_count_walk; > -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c index 6e43c95629ea..898a3cf814ba 100644 --- a/drivers/media/media-device.c +++ b/drivers/media/media-device.c @@ -90,18 +90,13 @@ static struct media_entity *find_entity(struct media_device *mdev, u32 id) id &= ~MEDIA_ENT_ID_FLAG_NEXT; - spin_lock(&mdev->lock); - media_device_for_each_entity(entity, mdev) { if (((media_entity_id(entity) == id) && !next) || ((media_entity_id(entity) > id) && next)) { - spin_unlock(&mdev->lock); return entity; } } - spin_unlock(&mdev->lock); - return NULL; } @@ -431,6 +426,7 @@ static long media_device_ioctl(struct file *filp, unsigned int cmd, struct media_device *dev = to_media_device(devnode); long ret; + mutex_lock(&dev->graph_mutex); switch (cmd) { case MEDIA_IOC_DEVICE_INFO: ret = media_device_get_info(dev, @@ -443,29 +439,24 @@ static long media_device_ioctl(struct file *filp, unsigned int cmd, break; case MEDIA_IOC_ENUM_LINKS: - mutex_lock(&dev->graph_mutex); ret = media_device_enum_links(dev, (struct media_links_enum __user *)arg); - mutex_unlock(&dev->graph_mutex); break; case MEDIA_IOC_SETUP_LINK: - mutex_lock(&dev->graph_mutex); ret = media_device_setup_link(dev, (struct media_link_desc __user *)arg); - mutex_unlock(&dev->graph_mutex); break; case MEDIA_IOC_G_TOPOLOGY: - mutex_lock(&dev->graph_mutex); ret = media_device_get_topology(dev, (struct media_v2_topology __user *)arg); - mutex_unlock(&dev->graph_mutex); break; default: ret = -ENOIOCTLCMD; } + mutex_unlock(&dev->graph_mutex); return ret; } @@ -590,12 +581,12 @@ int __must_check media_device_register_entity(struct media_device *mdev, if (!ida_pre_get(&mdev->entity_internal_idx, GFP_KERNEL)) return -ENOMEM; - spin_lock(&mdev->lock); + mutex_lock(&mdev->graph_mutex); ret = ida_get_new_above(&mdev->entity_internal_idx, 1, &entity->internal_idx); if (ret < 0) { - spin_unlock(&mdev->lock); + mutex_unlock(&mdev->graph_mutex); return ret; } @@ -615,9 +606,6 @@ int __must_check media_device_register_entity(struct media_device *mdev, (notify)->notify(entity, notify->notify_data); } - spin_unlock(&mdev->lock); - - mutex_lock(&mdev->graph_mutex); if (mdev->entity_internal_idx_max >= mdev->pm_count_walk.ent_enum.idx_max) { struct media_entity_graph new = { .top = 0 }; @@ -680,9 +668,9 @@ void media_device_unregister_entity(struct media_entity *entity) if (mdev == NULL) return; - spin_lock(&mdev->lock); + mutex_lock(&mdev->graph_mutex); __media_device_unregister_entity(entity); - spin_unlock(&mdev->lock); + mutex_unlock(&mdev->graph_mutex); } EXPORT_SYMBOL_GPL(media_device_unregister_entity); @@ -703,7 +691,6 @@ void media_device_init(struct media_device *mdev) INIT_LIST_HEAD(&mdev->pads); INIT_LIST_HEAD(&mdev->links); INIT_LIST_HEAD(&mdev->entity_notify); - spin_lock_init(&mdev->lock); mutex_init(&mdev->graph_mutex); ida_init(&mdev->entity_internal_idx); @@ -752,9 +739,9 @@ EXPORT_SYMBOL_GPL(__media_device_register); int __must_check media_device_register_entity_notify(struct media_device *mdev, struct media_entity_notify *nptr) { - spin_lock(&mdev->lock); + mutex_lock(&mdev->graph_mutex); list_add_tail(&nptr->list, &mdev->entity_notify); - spin_unlock(&mdev->lock); + mutex_unlock(&mdev->graph_mutex); return 0; } EXPORT_SYMBOL_GPL(media_device_register_entity_notify); @@ -771,9 +758,9 @@ static void __media_device_unregister_entity_notify(struct media_device *mdev, void media_device_unregister_entity_notify(struct media_device *mdev, struct media_entity_notify *nptr) { - spin_lock(&mdev->lock); + mutex_lock(&mdev->graph_mutex); __media_device_unregister_entity_notify(mdev, nptr); - spin_unlock(&mdev->lock); + mutex_unlock(&mdev->graph_mutex); } EXPORT_SYMBOL_GPL(media_device_unregister_entity_notify); @@ -787,11 +774,11 @@ void media_device_unregister(struct media_device *mdev) if (mdev == NULL) return; - spin_lock(&mdev->lock); + mutex_lock(&mdev->graph_mutex); /* Check if mdev was ever registered at all */ if (!media_devnode_is_registered(&mdev->devnode)) { - spin_unlock(&mdev->lock); + mutex_unlock(&mdev->graph_mutex); return; } @@ -811,7 +798,7 @@ void media_device_unregister(struct media_device *mdev) kfree(intf); } - spin_unlock(&mdev->lock); + mutex_unlock(&mdev->graph_mutex); device_remove_file(&mdev->devnode.dev, &dev_attr_model); media_devnode_unregister(&mdev->devnode); diff --git a/drivers/media/media-entity.c b/drivers/media/media-entity.c index e95070b3a3d4..c53c1d5589a0 100644 --- a/drivers/media/media-entity.c +++ b/drivers/media/media-entity.c @@ -219,7 +219,7 @@ int media_entity_pads_init(struct media_entity *entity, u16 num_pads, entity->pads = pads; if (mdev) - spin_lock(&mdev->lock); + mutex_lock(&mdev->graph_mutex); for (i = 0; i < num_pads; i++) { pads[i].entity = entity; @@ -230,7 +230,7 @@ int media_entity_pads_init(struct media_entity *entity, u16 num_pads, } if (mdev) - spin_unlock(&mdev->lock); + mutex_unlock(&mdev->graph_mutex); return 0; } @@ -747,9 +747,9 @@ void media_entity_remove_links(struct media_entity *entity) if (mdev == NULL) return; - spin_lock(&mdev->lock); + mutex_lock(&mdev->graph_mutex); __media_entity_remove_links(entity); - spin_unlock(&mdev->lock); + mutex_unlock(&mdev->graph_mutex); } EXPORT_SYMBOL_GPL(media_entity_remove_links); @@ -951,9 +951,9 @@ void media_remove_intf_link(struct media_link *link) if (mdev == NULL) return; - spin_lock(&mdev->lock); + mutex_lock(&mdev->graph_mutex); __media_remove_intf_link(link); - spin_unlock(&mdev->lock); + mutex_unlock(&mdev->graph_mutex); } EXPORT_SYMBOL_GPL(media_remove_intf_link); @@ -975,8 +975,8 @@ void media_remove_intf_links(struct media_interface *intf) if (mdev == NULL) return; - spin_lock(&mdev->lock); + mutex_lock(&mdev->graph_mutex); __media_remove_intf_links(intf); - spin_unlock(&mdev->lock); + mutex_unlock(&mdev->graph_mutex); } EXPORT_SYMBOL_GPL(media_remove_intf_links); diff --git a/include/media/media-device.h b/include/media/media-device.h index 07809f698464..b21ef244ad3e 100644 --- a/include/media/media-device.h +++ b/include/media/media-device.h @@ -25,7 +25,6 @@ #include <linux/list.h> #include <linux/mutex.h> -#include <linux/spinlock.h> #include <media/media-devnode.h> #include <media/media-entity.h> @@ -304,8 +303,7 @@ struct media_entity_notify { * @pads: List of registered pads * @links: List of registered links * @entity_notify: List of registered entity_notify callbacks - * @lock: Entities list lock - * @graph_mutex: Entities graph operation lock + * @graph_mutex: Protects access to struct media_device data * @pm_count_walk: Graph walk for power state walk. Access serialised using * graph_mutex. * @@ -371,8 +369,6 @@ struct media_device { /* notify callback list invoked when a new entity is registered */ struct list_head entity_notify; - /* Protects the graph objects creation/removal */ - spinlock_t lock; /* Serializes graph operations. */ struct mutex graph_mutex; struct media_entity_graph pm_count_walk;
Right now, the lock schema for media_device struct is messy, since sometimes, it is protected via a spin lock, while, for media graph traversal, it is protected by a mutex. Solve this conflict by always using a mutex. As a side effect, this prevents a bug when the media notifiers is called at atomic context, while running the notifier callback: BUG: sleeping function called from invalid context at mm/slub.c:1289 in_atomic(): 1, irqs_disabled(): 0, pid: 3479, name: modprobe 4 locks held by modprobe/3479: #0: (&dev->mutex){......}, at: [<ffffffff81ce8933>] __driver_attach+0xa3/0x160 #1: (&dev->mutex){......}, at: [<ffffffff81ce8941>] __driver_attach+0xb1/0x160 #2: (register_mutex#5){+.+.+.}, at: [<ffffffffa10596c7>] usb_audio_probe+0x257/0x1c90 [snd_usb_audio] #3: (&(&mdev->lock)->rlock){+.+.+.}, at: [<ffffffffa0e6051b>] media_device_register_entity+0x1cb/0x700 [media] CPU: 2 PID: 3479 Comm: modprobe Not tainted 4.5.0-rc3+ #49 Hardware name: /NUC5i7RYB, BIOS RYBDWi35.86A.0350.2015.0812.1722 08/12/2015 0000000000000000 ffff8803b3f6f288 ffffffff81933901 ffff8803c4bae000 ffff8803c4bae5c8 ffff8803b3f6f2b0 ffffffff811c6af5 ffff8803c4bae000 ffffffff8285d7f6 0000000000000509 ffff8803b3f6f2f0 ffffffff811c6ce5 Call Trace: [<ffffffff81933901>] dump_stack+0x85/0xc4 [<ffffffff811c6af5>] ___might_sleep+0x245/0x3a0 [<ffffffff811c6ce5>] __might_sleep+0x95/0x1a0 [<ffffffff8155aade>] kmem_cache_alloc_trace+0x20e/0x300 [<ffffffffa0e66e3d>] ? media_add_link+0x4d/0x140 [media] [<ffffffffa0e66e3d>] media_add_link+0x4d/0x140 [media] [<ffffffffa0e69931>] media_create_pad_link+0xa1/0x600 [media] [<ffffffffa0fe11b3>] au0828_media_graph_notify+0x173/0x360 [au0828] [<ffffffffa0e68a6a>] ? media_gobj_create+0x1ba/0x480 [media] [<ffffffffa0e606fb>] media_device_register_entity+0x3ab/0x700 [media] Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com> Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com> --- drivers/media/media-device.c | 39 +++++++++++++-------------------------- drivers/media/media-entity.c | 16 ++++++++-------- include/media/media-device.h | 6 +----- 3 files changed, 22 insertions(+), 39 deletions(-)