From: Christoph Hellwig <hch@xxxxxx> [ Upstream commit 2bd85221a625b316114bafaab527770b607095d3 ] The kobject embedded into the request_queue is used for the queue directory in sysfs, but that is a child of the gendisks directory and is intimately tied to it. Move this kobject to the gendisk and use a refcount_t in the request_queue for the actual request_queue refcounting that is completely unrelated to the device model. Signed-off-by: Christoph Hellwig <hch@xxxxxx> Link: https://lore.kernel.org/r/20221114042637.1009333-5-hch@xxxxxx Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Stable-dep-of: d36a9ea5e776 ("block: fix use-after-free of q->q_usage_counter") Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- block/blk-core.c | 42 ++++++++++++++++---- block/blk-crypto-sysfs.c | 4 +- block/blk-ia-ranges.c | 3 +- block/blk-sysfs.c | 86 +++++++++++----------------------------- block/blk.h | 4 -- block/bsg.c | 11 +++-- block/elevator.c | 2 +- include/linux/blkdev.h | 6 +-- 8 files changed, 71 insertions(+), 87 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index adc5fc562348..3920e101654f 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -60,12 +60,12 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(block_split); EXPORT_TRACEPOINT_SYMBOL_GPL(block_unplug); EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_insert); -DEFINE_IDA(blk_queue_ida); +static DEFINE_IDA(blk_queue_ida); /* * For queue allocation */ -struct kmem_cache *blk_requestq_cachep; +static struct kmem_cache *blk_requestq_cachep; /* * Controlling structure to kblockd @@ -253,19 +253,46 @@ void blk_clear_pm_only(struct request_queue *q) } EXPORT_SYMBOL_GPL(blk_clear_pm_only); +static void blk_free_queue_rcu(struct rcu_head *rcu_head) +{ + kmem_cache_free(blk_requestq_cachep, + container_of(rcu_head, struct request_queue, rcu_head)); +} + +static void blk_free_queue(struct request_queue *q) +{ + might_sleep(); + + percpu_ref_exit(&q->q_usage_counter); + + if (q->poll_stat) + blk_stat_remove_callback(q, q->poll_cb); + blk_stat_free_callback(q->poll_cb); + + blk_free_queue_stats(q->stats); + kfree(q->poll_stat); + + if (queue_is_mq(q)) + blk_mq_release(q); + + ida_free(&blk_queue_ida, q->id); + call_rcu(&q->rcu_head, blk_free_queue_rcu); +} + /** * blk_put_queue - decrement the request_queue refcount * @q: the request_queue structure to decrement the refcount for * - * Decrements the refcount of the request_queue kobject. When this reaches 0 - * we'll have blk_release_queue() called. + * Decrements the refcount of the request_queue and free it when the refcount + * reaches 0. * * Context: Any context, but the last reference must not be dropped from * atomic context. */ void blk_put_queue(struct request_queue *q) { - kobject_put(&q->kobj); + if (refcount_dec_and_test(&q->refs)) + blk_free_queue(q); } EXPORT_SYMBOL(blk_put_queue); @@ -400,8 +427,7 @@ struct request_queue *blk_alloc_queue(int node_id) INIT_WORK(&q->timeout_work, blk_timeout_work); INIT_LIST_HEAD(&q->icq_list); - kobject_init(&q->kobj, &blk_queue_ktype); - + refcount_set(&q->refs, 1); mutex_init(&q->debugfs_mutex); mutex_init(&q->sysfs_lock); mutex_init(&q->sysfs_dir_lock); @@ -445,7 +471,7 @@ bool blk_get_queue(struct request_queue *q) { if (unlikely(blk_queue_dying(q))) return false; - kobject_get(&q->kobj); + refcount_inc(&q->refs); return true; } EXPORT_SYMBOL(blk_get_queue); diff --git a/block/blk-crypto-sysfs.c b/block/blk-crypto-sysfs.c index e05f145cd797..55268edc0625 100644 --- a/block/blk-crypto-sysfs.c +++ b/block/blk-crypto-sysfs.c @@ -140,8 +140,8 @@ int blk_crypto_sysfs_register(struct gendisk *disk) return -ENOMEM; obj->profile = q->crypto_profile; - err = kobject_init_and_add(&obj->kobj, &blk_crypto_ktype, &q->kobj, - "crypto"); + err = kobject_init_and_add(&obj->kobj, &blk_crypto_ktype, + &disk->queue_kobj, "crypto"); if (err) { kobject_put(&obj->kobj); return err; diff --git a/block/blk-ia-ranges.c b/block/blk-ia-ranges.c index 2bd1d311033b..2141931ddd37 100644 --- a/block/blk-ia-ranges.c +++ b/block/blk-ia-ranges.c @@ -123,7 +123,8 @@ int disk_register_independent_access_ranges(struct gendisk *disk) */ WARN_ON(iars->sysfs_registered); ret = kobject_init_and_add(&iars->kobj, &blk_ia_ranges_ktype, - &q->kobj, "%s", "independent_access_ranges"); + &disk->queue_kobj, "%s", + "independent_access_ranges"); if (ret) { disk->ia_ranges = NULL; kobject_put(&iars->kobj); diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 02931b6f25c5..f32c195c9767 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -680,8 +680,8 @@ static struct attribute *queue_attrs[] = { static umode_t queue_attr_visible(struct kobject *kobj, struct attribute *attr, int n) { - struct request_queue *q = - container_of(kobj, struct request_queue, kobj); + struct gendisk *disk = container_of(kobj, struct gendisk, queue_kobj); + struct request_queue *q = disk->queue; if (attr == &queue_io_timeout_entry.attr && (!q->mq_ops || !q->mq_ops->timeout)) @@ -707,8 +707,8 @@ static ssize_t queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page) { struct queue_sysfs_entry *entry = to_queue(attr); - struct request_queue *q = - container_of(kobj, struct request_queue, kobj); + struct gendisk *disk = container_of(kobj, struct gendisk, queue_kobj); + struct request_queue *q = disk->queue; ssize_t res; if (!entry->show) @@ -724,63 +724,19 @@ queue_attr_store(struct kobject *kobj, struct attribute *attr, const char *page, size_t length) { struct queue_sysfs_entry *entry = to_queue(attr); - struct request_queue *q; + struct gendisk *disk = container_of(kobj, struct gendisk, queue_kobj); + struct request_queue *q = disk->queue; ssize_t res; if (!entry->store) return -EIO; - q = container_of(kobj, struct request_queue, kobj); mutex_lock(&q->sysfs_lock); res = entry->store(q, page, length); mutex_unlock(&q->sysfs_lock); return res; } -static void blk_free_queue_rcu(struct rcu_head *rcu_head) -{ - kmem_cache_free(blk_requestq_cachep, - container_of(rcu_head, struct request_queue, rcu_head)); -} - -/** - * blk_release_queue - releases all allocated resources of the request_queue - * @kobj: pointer to a kobject, whose container is a request_queue - * - * This function releases all allocated resources of the request queue. - * - * The struct request_queue refcount is incremented with blk_get_queue() and - * decremented with blk_put_queue(). Once the refcount reaches 0 this function - * is called. - * - * Drivers exist which depend on the release of the request_queue to be - * synchronous, it should not be deferred. - * - * Context: can sleep - */ -static void blk_release_queue(struct kobject *kobj) -{ - struct request_queue *q = - container_of(kobj, struct request_queue, kobj); - - might_sleep(); - - percpu_ref_exit(&q->q_usage_counter); - - if (q->poll_stat) - blk_stat_remove_callback(q, q->poll_cb); - blk_stat_free_callback(q->poll_cb); - - blk_free_queue_stats(q->stats); - kfree(q->poll_stat); - - if (queue_is_mq(q)) - blk_mq_release(q); - - ida_free(&blk_queue_ida, q->id); - call_rcu(&q->rcu_head, blk_free_queue_rcu); -} - static const struct sysfs_ops queue_sysfs_ops = { .show = queue_attr_show, .store = queue_attr_store, @@ -791,10 +747,15 @@ static const struct attribute_group *blk_queue_attr_groups[] = { NULL }; -struct kobj_type blk_queue_ktype = { +static void blk_queue_release(struct kobject *kobj) +{ + /* nothing to do here, all data is associated with the parent gendisk */ +} + +static struct kobj_type blk_queue_ktype = { .default_groups = blk_queue_attr_groups, .sysfs_ops = &queue_sysfs_ops, - .release = blk_release_queue, + .release = blk_queue_release, }; static void blk_debugfs_remove(struct gendisk *disk) @@ -820,20 +781,20 @@ int blk_register_queue(struct gendisk *disk) int ret; mutex_lock(&q->sysfs_dir_lock); - ret = kobject_add(&q->kobj, &disk_to_dev(disk)->kobj, "queue"); + kobject_init(&disk->queue_kobj, &blk_queue_ktype); + ret = kobject_add(&disk->queue_kobj, &disk_to_dev(disk)->kobj, "queue"); if (ret < 0) - goto out_unlock_dir; + goto out_put_queue_kobj; if (queue_is_mq(q)) { ret = blk_mq_sysfs_register(disk); if (ret) - goto out_del_queue_kobj; + goto out_put_queue_kobj; } mutex_lock(&q->sysfs_lock); mutex_lock(&q->debugfs_mutex); - q->debugfs_dir = debugfs_create_dir(kobject_name(q->kobj.parent), - blk_debugfs_root); + q->debugfs_dir = debugfs_create_dir(disk->disk_name, blk_debugfs_root); if (queue_is_mq(q)) blk_mq_debugfs_register(q); mutex_unlock(&q->debugfs_mutex); @@ -857,7 +818,7 @@ int blk_register_queue(struct gendisk *disk) blk_throtl_register_queue(q); /* Now everything is ready and send out KOBJ_ADD uevent */ - kobject_uevent(&q->kobj, KOBJ_ADD); + kobject_uevent(&disk->queue_kobj, KOBJ_ADD); if (q->elevator) kobject_uevent(&q->elevator->kobj, KOBJ_ADD); mutex_unlock(&q->sysfs_lock); @@ -886,9 +847,8 @@ int blk_register_queue(struct gendisk *disk) out_debugfs_remove: blk_debugfs_remove(disk); mutex_unlock(&q->sysfs_lock); -out_del_queue_kobj: - kobject_del(&q->kobj); -out_unlock_dir: +out_put_queue_kobj: + kobject_put(&disk->queue_kobj); mutex_unlock(&q->sysfs_dir_lock); return ret; } @@ -935,8 +895,8 @@ void blk_unregister_queue(struct gendisk *disk) mutex_unlock(&q->sysfs_lock); /* Now that we've deleted all child objects, we can delete the queue. */ - kobject_uevent(&q->kobj, KOBJ_REMOVE); - kobject_del(&q->kobj); + kobject_uevent(&disk->queue_kobj, KOBJ_REMOVE); + kobject_del(&disk->queue_kobj); mutex_unlock(&q->sysfs_dir_lock); blk_debugfs_remove(disk); diff --git a/block/blk.h b/block/blk.h index 5040c5b4ee70..bf20ed1c3054 100644 --- a/block/blk.h +++ b/block/blk.h @@ -26,10 +26,6 @@ struct blk_flush_queue { spinlock_t mq_flush_lock; }; -extern struct kmem_cache *blk_requestq_cachep; -extern struct kobj_type blk_queue_ktype; -extern struct ida blk_queue_ida; - bool is_flush_rq(struct request *req); struct blk_flush_queue *blk_alloc_flush_queue(int node, int cmd_size, diff --git a/block/bsg.c b/block/bsg.c index 2ab1351eb082..8eba57b9bb46 100644 --- a/block/bsg.c +++ b/block/bsg.c @@ -175,8 +175,10 @@ static void bsg_device_release(struct device *dev) void bsg_unregister_queue(struct bsg_device *bd) { - if (bd->queue->kobj.sd) - sysfs_remove_link(&bd->queue->kobj, "bsg"); + struct gendisk *disk = bd->queue->disk; + + if (disk && disk->queue_kobj.sd) + sysfs_remove_link(&disk->queue_kobj, "bsg"); cdev_device_del(&bd->cdev, &bd->device); put_device(&bd->device); } @@ -216,8 +218,9 @@ struct bsg_device *bsg_register_queue(struct request_queue *q, if (ret) goto out_put_device; - if (q->kobj.sd) { - ret = sysfs_create_link(&q->kobj, &bd->device.kobj, "bsg"); + if (q->disk && q->disk->queue_kobj.sd) { + ret = sysfs_create_link(&q->disk->queue_kobj, &bd->device.kobj, + "bsg"); if (ret) goto out_device_del; } diff --git a/block/elevator.c b/block/elevator.c index bd71f0fc4e4b..ac096f494911 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -499,7 +499,7 @@ int elv_register_queue(struct request_queue *q, bool uevent) lockdep_assert_held(&q->sysfs_lock); - error = kobject_add(&e->kobj, &q->kobj, "%s", "iosched"); + error = kobject_add(&e->kobj, &q->disk->queue_kobj, "iosched"); if (!error) { struct elv_fs_entry *attr = e->type->elevator_attrs; if (attr) { diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 0526f1c49fc6..c712841ef64b 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -155,6 +155,7 @@ struct gendisk { unsigned open_partitions; /* number of open partitions */ struct backing_dev_info *bdi; + struct kobject queue_kobj; /* the queue/ directory */ struct kobject *slave_dir; #ifdef CONFIG_BLOCK_HOLDER_DEPRECATED struct list_head slave_bdevs; @@ -437,10 +438,7 @@ struct request_queue { struct gendisk *disk; - /* - * queue kobject - */ - struct kobject kobj; + refcount_t refs; /* * mq queue kobject -- 2.35.1
