@@ -946,6 +946,20 @@ static void blk_rq_timed_out_timer(struct timer_list *t)
kblockd_schedule_work(&q->timeout_work);
}
+/**
+ * blk_alloc_queue_node - allocate a request queue
+ * @gfp_mask: memory allocation flags
+ * @node_id: NUMA node to allocate memory from
+ * @lock: Pointer to a spinlock that will be used to e.g. serialize calls to
+ * the legacy .request_fn(). Only set this pointer for queues that use
+ * legacy mode and not for queues that use blk-mq.
+ *
+ * Note: pass the queue lock as the third argument to this function instead of
+ * setting the queue lock pointer explicitly to avoid triggering a crash in
+ * the blkcg throttling code. That code namely makes sysfs attributes visible
+ * in user space before this function returns and the show methods of these
+ * sysfs attributes use the queue lock.
+ */
struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id,
spinlock_t *lock)
{
@@ -998,11 +1012,7 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id,
mutex_init(&q->sysfs_lock);
spin_lock_init(&q->__queue_lock);
- /*
- * By default initialize queue_lock to internal lock and driver can
- * override it later if need be.
- */
- q->queue_lock = &q->__queue_lock;
+ q->queue_lock = lock ? : &q->__queue_lock;
/*
* A queue starts its life with bypass turned on to avoid
@@ -1089,13 +1099,11 @@ blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id)
{
struct request_queue *q;
- q = blk_alloc_queue_node(GFP_KERNEL, node_id, NULL);
+ q = blk_alloc_queue_node(GFP_KERNEL, node_id, lock);
if (!q)
return NULL;
q->request_fn = rfn;
- if (lock)
- q->queue_lock = lock;
if (blk_init_allocated_queue(q) < 0) {
blk_cleanup_queue(q);
return NULL;
@@ -2822,7 +2822,7 @@ enum drbd_ret_code drbd_create_device(struct drbd_config_context *adm_ctx, unsig
drbd_init_set_defaults(device);
- q = blk_alloc_queue(GFP_KERNEL);
+ q = blk_alloc_queue_node(GFP_KERNEL, NUMA_NO_NODE, &resource->req_lock);
if (!q)
goto out_no_q;
device->rq_queue = q;
@@ -2854,7 +2854,6 @@ enum drbd_ret_code drbd_create_device(struct drbd_config_context *adm_ctx, unsig
/* Setting the max_hw_sectors to an odd value of 8kibyte here
This triggers a max_bio_size message upon first attach or connect */
blk_queue_max_hw_sectors(q, DRBD_MAX_BIO_SIZE_SAFE >> 8);
- q->queue_lock = &resource->req_lock;
device->md_io.page = alloc_page(GFP_KERNEL);
if (!device->md_io.page)
@@ -888,13 +888,14 @@ static int mm_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
card->Active = -1; /* no page is active */
card->bio = NULL;
card->biotail = &card->bio;
+ spin_lock_init(&card->lock);
- card->queue = blk_alloc_queue(GFP_KERNEL);
+ card->queue = blk_alloc_queue_node(GFP_KERNEL, NUMA_NO_NODE,
+ &card->lock);
if (!card->queue)
goto failed_alloc;
blk_queue_make_request(card->queue, mm_make_request);
- card->queue->queue_lock = &card->lock;
card->queue->queuedata = card;
tasklet_init(&card->tasklet, process_page, (unsigned long)card);
@@ -968,8 +969,6 @@ static int mm_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
dev_printk(KERN_INFO, &card->dev->dev,
"Window size %d bytes, IRQ %d\n", data, dev->irq);
- spin_lock_init(&card->lock);
-
pci_set_drvdata(dev, card);
if (pci_write_cmd != 0x0F) /* If not Memory Write & Invalidate */
@@ -216,10 +216,9 @@ int mmc_init_queue(struct mmc_queue *mq, struct mmc_card *card,
int ret = -ENOMEM;
mq->card = card;
- mq->queue = blk_alloc_queue(GFP_KERNEL);
+ mq->queue = blk_alloc_queue_node(GFP_KERNEL, NUMA_NO_NODE, lock);
if (!mq->queue)
return -ENOMEM;
- mq->queue->queue_lock = lock;
mq->queue->request_fn = mmc_request_fn;
mq->queue->init_rq_fn = mmc_init_request;
mq->queue->exit_rq_fn = mmc_exit_request;
Initialize the request queue lock earlier such that the following race can no longer occur: blk_init_queue_node blkcg_print_blkgs blk_alloc_queue_node (1) q->queue_lock = &q->__queue_lock (2) blkcg_init_queue(q) (3) spin_lock_irq(blkg->q->queue_lock) (4) q->queue_lock = lock (5) spin_unlock_irq(blkg->q->queue_lock) (6) (1) allocate an uninitialized queue; (2) initialize queue_lock to its default internal lock; (3) initialize blkcg part of request queue, which will create blkg and then insert it to blkg_list; (4) traverse blkg_list and find the created blkg, and then take its queue lock, here it is the default *internal lock*; (5) *race window*, now queue_lock is overridden with *driver specified lock*; (6) now unlock *driver specified lock*, not the locked *internal lock*, unlock balance breaks. The changes in this patch are as follows: - Move the .queue_lock initialization from blk_init_queue_node() into blk_alloc_queue_node(). - For all all block drivers that initialize .queue_lock explicitly, change the blk_alloc_queue() call in the driver into a blk_alloc_queue_node() call and remove the explicit .queue_lock initialization. Additionally, initialize the spin lock that will be used as queue lock earlier if necessary. Reported-by: Joseph Qi <joseph.qi@linux.alibaba.com> Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: Philipp Reisner <philipp.reisner@linbit.com> Cc: Ulf Hansson <ulf.hansson@linaro.org> Cc: Kees Cook <keescook@chromium.org> Cc: <stable@vger.kernel.org> --- block/blk-core.c | 24 ++++++++++++++++-------- drivers/block/drbd/drbd_main.c | 3 +-- drivers/block/umem.c | 7 +++---- drivers/mmc/core/queue.c | 3 +-- 4 files changed, 21 insertions(+), 16 deletions(-)