[4.19-stable] SCSI: fix queue cleanup race before scsi_requeue_run_queue is done
diff mbox series

Message ID 1566182345-7544-1-git-send-email-zhengbin13@huawei.com
State Not Applicable
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Series
  • [4.19-stable] SCSI: fix queue cleanup race before scsi_requeue_run_queue is done
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Commit Message

zhengbin Aug. 19, 2019, 2:39 a.m. UTC
KASAN reports a use-after-free in 4.19-stable,
which won't happen after commit 47cdee29ef9d
("block: move blk_exit_queue into __blk_release_queue").
However, backport this patch to 4.19-stable will be a lot of work and
the risk is great. Moreover, we should make sure scsi_requeue_run_queue
is done before blk_cleanup_queue.

BUG: KASAN: use-after-free in dd_has_work+0x50/0xe8
Read of size 8 at addr ffff808b57c6f168 by task kworker/53:1H/6910

CPU: 53 PID: 6910 Comm: kworker/53:1H Kdump: loaded Tainted: G
Hardware name: Huawei TaiShan 2280 /BC11SPCD, BIOS 1.59 01/31/2019
Workqueue: kblockd scsi_requeue_run_queue
Call trace:
 dump_backtrace+0x0/0x270
 show_stack+0x24/0x30
 dump_stack+0xb4/0xe4
 print_address_description+0x68/0x278
 kasan_report+0x204/0x330
 __asan_load8+0x88/0xb0
 dd_has_work+0x50/0xe8
 blk_mq_run_hw_queue+0x19c/0x218
 blk_mq_run_hw_queues+0x7c/0xb0
 scsi_run_queue+0x3ec/0x520
 scsi_requeue_run_queue+0x2c/0x38
 process_one_work+0x2e4/0x6d8
 worker_thread+0x6c/0x6a8
 kthread+0x1b4/0x1c0
 ret_from_fork+0x10/0x18

Allocated by task 46843:
 kasan_kmalloc+0xe0/0x190
 kmem_cache_alloc_node_trace+0x10c/0x258
 dd_init_queue+0x68/0x190
 blk_mq_init_sched+0x1cc/0x300
 elevator_init_mq+0x90/0xe0
 blk_mq_init_allocated_queue+0x700/0x728
 blk_mq_init_queue+0x48/0x90
 scsi_mq_alloc_queue+0x34/0xb0
 scsi_alloc_sdev+0x340/0x530
 scsi_probe_and_add_lun+0x46c/0x1260
 __scsi_scan_target+0x1b8/0x7b0
 scsi_scan_target+0x140/0x150
 fc_scsi_scan_rport+0x164/0x178 [scsi_transport_fc]
 process_one_work+0x2e4/0x6d8
 worker_thread+0x6c/0x6a8
 kthread+0x1b4/0x1c0
 ret_from_fork+0x10/0x18

Freed by task 46843:
 __kasan_slab_free+0x120/0x228
 kasan_slab_free+0x10/0x18
 kfree+0x88/0x218
 dd_exit_queue+0x5c/0x78
 blk_mq_exit_sched+0x104/0x130
 elevator_exit+0xa8/0xc8
 blk_exit_queue+0x48/0x78
 blk_cleanup_queue+0x170/0x248
 __scsi_remove_device+0x84/0x1b0
 scsi_probe_and_add_lun+0xd00/0x1260
 __scsi_scan_target+0x1b8/0x7b0
 scsi_scan_target+0x140/0x150
 fc_scsi_scan_rport+0x164/0x178 [scsi_transport_fc]
 process_one_work+0x2e4/0x6d8
 worker_thread+0x6c/0x6a8
 kthread+0x1b4/0x1c0
 ret_from_fork+0x10/0x18

Fixes: 8dc765d438f1 ("SCSI: fix queue cleanup race before queue initialization is done")
Signed-off-by: zhengbin <zhengbin13@huawei.com>
---
 drivers/scsi/scsi_lib.c   | 24 ++++++++++++++++++------
 drivers/scsi/scsi_sysfs.c |  3 ++-
 2 files changed, 20 insertions(+), 7 deletions(-)

--
2.7.4

Comments

Ming Lei Aug. 19, 2019, 4:08 a.m. UTC | #1
On Mon, Aug 19, 2019 at 10:39:05AM +0800, zhengbin wrote:
> KASAN reports a use-after-free in 4.19-stable,
> which won't happen after commit 47cdee29ef9d
> ("block: move blk_exit_queue into __blk_release_queue").
> However, backport this patch to 4.19-stable will be a lot of work and
> the risk is great. Moreover, we should make sure scsi_requeue_run_queue
> is done before blk_cleanup_queue.

I have backported that patchset to v4.18 based kernel, and it won't
take lots of work at all.

> 
> BUG: KASAN: use-after-free in dd_has_work+0x50/0xe8
> Read of size 8 at addr ffff808b57c6f168 by task kworker/53:1H/6910
> 
> CPU: 53 PID: 6910 Comm: kworker/53:1H Kdump: loaded Tainted: G
> Hardware name: Huawei TaiShan 2280 /BC11SPCD, BIOS 1.59 01/31/2019
> Workqueue: kblockd scsi_requeue_run_queue
> Call trace:
>  dump_backtrace+0x0/0x270
>  show_stack+0x24/0x30
>  dump_stack+0xb4/0xe4
>  print_address_description+0x68/0x278
>  kasan_report+0x204/0x330
>  __asan_load8+0x88/0xb0
>  dd_has_work+0x50/0xe8
>  blk_mq_run_hw_queue+0x19c/0x218
>  blk_mq_run_hw_queues+0x7c/0xb0
>  scsi_run_queue+0x3ec/0x520
>  scsi_requeue_run_queue+0x2c/0x38
>  process_one_work+0x2e4/0x6d8
>  worker_thread+0x6c/0x6a8
>  kthread+0x1b4/0x1c0
>  ret_from_fork+0x10/0x18
> 
> Allocated by task 46843:
>  kasan_kmalloc+0xe0/0x190
>  kmem_cache_alloc_node_trace+0x10c/0x258
>  dd_init_queue+0x68/0x190
>  blk_mq_init_sched+0x1cc/0x300
>  elevator_init_mq+0x90/0xe0
>  blk_mq_init_allocated_queue+0x700/0x728
>  blk_mq_init_queue+0x48/0x90
>  scsi_mq_alloc_queue+0x34/0xb0
>  scsi_alloc_sdev+0x340/0x530
>  scsi_probe_and_add_lun+0x46c/0x1260
>  __scsi_scan_target+0x1b8/0x7b0
>  scsi_scan_target+0x140/0x150
>  fc_scsi_scan_rport+0x164/0x178 [scsi_transport_fc]
>  process_one_work+0x2e4/0x6d8
>  worker_thread+0x6c/0x6a8
>  kthread+0x1b4/0x1c0
>  ret_from_fork+0x10/0x18
> 
> Freed by task 46843:
>  __kasan_slab_free+0x120/0x228
>  kasan_slab_free+0x10/0x18
>  kfree+0x88/0x218
>  dd_exit_queue+0x5c/0x78
>  blk_mq_exit_sched+0x104/0x130
>  elevator_exit+0xa8/0xc8
>  blk_exit_queue+0x48/0x78
>  blk_cleanup_queue+0x170/0x248
>  __scsi_remove_device+0x84/0x1b0
>  scsi_probe_and_add_lun+0xd00/0x1260
>  __scsi_scan_target+0x1b8/0x7b0
>  scsi_scan_target+0x140/0x150
>  fc_scsi_scan_rport+0x164/0x178 [scsi_transport_fc]
>  process_one_work+0x2e4/0x6d8
>  worker_thread+0x6c/0x6a8
>  kthread+0x1b4/0x1c0
>  ret_from_fork+0x10/0x18
> 
> Fixes: 8dc765d438f1 ("SCSI: fix queue cleanup race before queue initialization is done")
> Signed-off-by: zhengbin <zhengbin13@huawei.com>
> ---
>  drivers/scsi/scsi_lib.c   | 24 ++++++++++++++++++------
>  drivers/scsi/scsi_sysfs.c |  3 ++-
>  2 files changed, 20 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
> index 75b926e..42f1475 100644
> --- a/drivers/scsi/scsi_lib.c
> +++ b/drivers/scsi/scsi_lib.c
> @@ -208,7 +208,13 @@ static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, bool unbusy)
>  	}
>  	spin_lock_irqsave(q->queue_lock, flags);
>  	blk_requeue_request(q, cmd->request);
> -	kblockd_schedule_work(&device->requeue_work);
> +	/*
> +	 * need to get q_usage_counter which will be
> +	 * put in scsi_requeue_run_queue.
> +	 */
> +	percpu_ref_get(&q->q_usage_counter);
> +	if (!kblockd_schedule_work(&device->requeue_work))
> +		percpu_ref_put(&q->q_usage_counter);
>  	spin_unlock_irqrestore(q->queue_lock, flags);
>  }
> 
> @@ -548,6 +554,11 @@ void scsi_requeue_run_queue(struct work_struct *work)
>  	sdev = container_of(work, struct scsi_device, requeue_work);
>  	q = sdev->request_queue;
>  	scsi_run_queue(q);
> +	/*
> +	 * need to put q_usage_counter which is got in
> +	 * scsi_end_request or __scsi_queue_insert.
> +	 */
> +	percpu_ref_put(&q->q_usage_counter);
>  }
> 
>  /*
> @@ -706,12 +717,13 @@ static bool scsi_end_request(struct request *req, blk_status_t error,
>  		__blk_mq_end_request(req, error);
> 
>  		if (scsi_target(sdev)->single_lun ||
> -		    !list_empty(&sdev->host->starved_list))
> -			kblockd_schedule_work(&sdev->requeue_work);
> -		else
> +		    !list_empty(&sdev->host->starved_list)) {
> +			if (!kblockd_schedule_work(&sdev->requeue_work))
> +				percpu_ref_put(&q->q_usage_counter);
> +		} else {
>  			blk_mq_run_hw_queues(q, true);
> -
> -		percpu_ref_put(&q->q_usage_counter);
> +			percpu_ref_put(&q->q_usage_counter);
> +		}
>  	} else {
>  		unsigned long flags;
> 
> diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
> index 3aee946..2dc422e 100644
> --- a/drivers/scsi/scsi_sysfs.c
> +++ b/drivers/scsi/scsi_sysfs.c
> @@ -1392,7 +1392,8 @@ void __scsi_remove_device(struct scsi_device *sdev)
>  	mutex_unlock(&sdev->state_mutex);
> 
>  	blk_cleanup_queue(sdev->request_queue);
> -	cancel_work_sync(&sdev->requeue_work);
> +	if (cancel_work_sync(&sdev->requeue_work))
> +		percpu_ref_put(&sdev->request_queue->q_usage_counter);
> 
>  	if (sdev->host->hostt->slave_destroy)
>  		sdev->host->hostt->slave_destroy(sdev);

Getting/putting the percpu ref from different contexts is just a
nightmare for maintaining the correctness.


Thanks,
Ming
zhengbin Aug. 19, 2019, 11:48 a.m. UTC | #2
On 2019/8/19 12:08, Ming Lei wrote:
> On Mon, Aug 19, 2019 at 10:39:05AM +0800, zhengbin wrote:
>> KASAN reports a use-after-free in 4.19-stable,
>> which won't happen after commit 47cdee29ef9d
>> ("block: move blk_exit_queue into __blk_release_queue").
>> However, backport this patch to 4.19-stable will be a lot of work and
>> the risk is great. Moreover, we should make sure scsi_requeue_run_queue
>> is done before blk_cleanup_queue.
> I have backported that patchset to v4.18 based kernel, and it won't
> take lots of work at all.

In fact, I want to backport it to 4.19, if backport, we need to do:

1. need to backport 0d945c1f966b ("block: remove the queue_lock indirection"), cause commit 47cdee29ef9d

("block: move blk_exit_queue into __blk_release_queue") reverts a063057d7c73

("block: Fix a race between request queue removal and the block cgroup controller"), if we do not backport 0d945c1f966b,

the bug fixed by a063057d7c73 will exist too.

2. If we backport 0d945c1f966b, see the comment: "With the legacy request path gone there is no good reason to keep queue_lock as a pointer".

we need to backport the driver patches which kill the queue_lock. For example:

89c6b1650969 ("paride: convert pcd to blk-mq")  --->the second para of blk_init_queue is queue_lock

99fe8b02a825 ("paride: convert pd to blk-mq")

...

3. In SCSI, 4.19-stable has blk-sq(single queue) & mq.  Blk-sq uses queue_lock, while these need  to adapt. For example:

scsi_lib.c:     spin_lock_irqsave(q->queue_lock, flags);
scsi_lib.c:     spin_unlock_irqrestore(q->queue_lock, flags);
scsi_lib.c:              * drops the queue_lock and can add us back to the
scsi_lib.c:     spin_lock_irqsave(q->queue_lock, flags);
scsi_lib.c:     spin_unlock_irqrestore(q->queue_lock, flags);
scsi_lib.c:             spin_lock_irqsave(q->queue_lock, flags);
scsi_lib.c:             spin_unlock_irqrestore(q->queue_lock, flags);
scsi_lib.c: * Called with the queue_lock held.
...

>> BUG: KASAN: use-after-free in dd_has_work+0x50/0xe8
>> Read of size 8 at addr ffff808b57c6f168 by task kworker/53:1H/6910
>>
>> CPU: 53 PID: 6910 Comm: kworker/53:1H Kdump: loaded Tainted: G
>> Hardware name: Huawei TaiShan 2280 /BC11SPCD, BIOS 1.59 01/31/2019
>> Workqueue: kblockd scsi_requeue_run_queue
>> Call trace:
>>  dump_backtrace+0x0/0x270
>>  show_stack+0x24/0x30
>>  dump_stack+0xb4/0xe4
>>  print_address_description+0x68/0x278
>>  kasan_report+0x204/0x330
>>  __asan_load8+0x88/0xb0
>>  dd_has_work+0x50/0xe8
>>  blk_mq_run_hw_queue+0x19c/0x218
>>  blk_mq_run_hw_queues+0x7c/0xb0
>>  scsi_run_queue+0x3ec/0x520
>>  scsi_requeue_run_queue+0x2c/0x38
>>  process_one_work+0x2e4/0x6d8
>>  worker_thread+0x6c/0x6a8
>>  kthread+0x1b4/0x1c0
>>  ret_from_fork+0x10/0x18
>>
>> Allocated by task 46843:
>>  kasan_kmalloc+0xe0/0x190
>>  kmem_cache_alloc_node_trace+0x10c/0x258
>>  dd_init_queue+0x68/0x190
>>  blk_mq_init_sched+0x1cc/0x300
>>  elevator_init_mq+0x90/0xe0
>>  blk_mq_init_allocated_queue+0x700/0x728
>>  blk_mq_init_queue+0x48/0x90
>>  scsi_mq_alloc_queue+0x34/0xb0
>>  scsi_alloc_sdev+0x340/0x530
>>  scsi_probe_and_add_lun+0x46c/0x1260
>>  __scsi_scan_target+0x1b8/0x7b0
>>  scsi_scan_target+0x140/0x150
>>  fc_scsi_scan_rport+0x164/0x178 [scsi_transport_fc]
>>  process_one_work+0x2e4/0x6d8
>>  worker_thread+0x6c/0x6a8
>>  kthread+0x1b4/0x1c0
>>  ret_from_fork+0x10/0x18
>>
>> Freed by task 46843:
>>  __kasan_slab_free+0x120/0x228
>>  kasan_slab_free+0x10/0x18
>>  kfree+0x88/0x218
>>  dd_exit_queue+0x5c/0x78
>>  blk_mq_exit_sched+0x104/0x130
>>  elevator_exit+0xa8/0xc8
>>  blk_exit_queue+0x48/0x78
>>  blk_cleanup_queue+0x170/0x248
>>  __scsi_remove_device+0x84/0x1b0
>>  scsi_probe_and_add_lun+0xd00/0x1260
>>  __scsi_scan_target+0x1b8/0x7b0
>>  scsi_scan_target+0x140/0x150
>>  fc_scsi_scan_rport+0x164/0x178 [scsi_transport_fc]
>>  process_one_work+0x2e4/0x6d8
>>  worker_thread+0x6c/0x6a8
>>  kthread+0x1b4/0x1c0
>>  ret_from_fork+0x10/0x18
>>
>> Fixes: 8dc765d438f1 ("SCSI: fix queue cleanup race before queue initialization is done")
>> Signed-off-by: zhengbin <zhengbin13@huawei.com>
>> ---
>>  drivers/scsi/scsi_lib.c   | 24 ++++++++++++++++++------
>>  drivers/scsi/scsi_sysfs.c |  3 ++-
>>  2 files changed, 20 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
>> index 75b926e..42f1475 100644
>> --- a/drivers/scsi/scsi_lib.c
>> +++ b/drivers/scsi/scsi_lib.c
>> @@ -208,7 +208,13 @@ static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, bool unbusy)
>>  	}
>>  	spin_lock_irqsave(q->queue_lock, flags);
>>  	blk_requeue_request(q, cmd->request);
>> -	kblockd_schedule_work(&device->requeue_work);
>> +	/*
>> +	 * need to get q_usage_counter which will be
>> +	 * put in scsi_requeue_run_queue.
>> +	 */
>> +	percpu_ref_get(&q->q_usage_counter);
>> +	if (!kblockd_schedule_work(&device->requeue_work))
>> +		percpu_ref_put(&q->q_usage_counter);
>>  	spin_unlock_irqrestore(q->queue_lock, flags);
>>  }
>>
>> @@ -548,6 +554,11 @@ void scsi_requeue_run_queue(struct work_struct *work)
>>  	sdev = container_of(work, struct scsi_device, requeue_work);
>>  	q = sdev->request_queue;
>>  	scsi_run_queue(q);
>> +	/*
>> +	 * need to put q_usage_counter which is got in
>> +	 * scsi_end_request or __scsi_queue_insert.
>> +	 */
>> +	percpu_ref_put(&q->q_usage_counter);
>>  }
>>
>>  /*
>> @@ -706,12 +717,13 @@ static bool scsi_end_request(struct request *req, blk_status_t error,
>>  		__blk_mq_end_request(req, error);
>>
>>  		if (scsi_target(sdev)->single_lun ||
>> -		    !list_empty(&sdev->host->starved_list))
>> -			kblockd_schedule_work(&sdev->requeue_work);
>> -		else
>> +		    !list_empty(&sdev->host->starved_list)) {
>> +			if (!kblockd_schedule_work(&sdev->requeue_work))
>> +				percpu_ref_put(&q->q_usage_counter);
>> +		} else {
>>  			blk_mq_run_hw_queues(q, true);
>> -
>> -		percpu_ref_put(&q->q_usage_counter);
>> +			percpu_ref_put(&q->q_usage_counter);
>> +		}
>>  	} else {
>>  		unsigned long flags;
>>
>> diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
>> index 3aee946..2dc422e 100644
>> --- a/drivers/scsi/scsi_sysfs.c
>> +++ b/drivers/scsi/scsi_sysfs.c
>> @@ -1392,7 +1392,8 @@ void __scsi_remove_device(struct scsi_device *sdev)
>>  	mutex_unlock(&sdev->state_mutex);
>>
>>  	blk_cleanup_queue(sdev->request_queue);
>> -	cancel_work_sync(&sdev->requeue_work);
>> +	if (cancel_work_sync(&sdev->requeue_work))
>> +		percpu_ref_put(&sdev->request_queue->q_usage_counter);
>>
>>  	if (sdev->host->hostt->slave_destroy)
>>  		sdev->host->hostt->slave_destroy(sdev);
> Getting/putting the percpu ref from different contexts is just a
> nightmare for maintaining the correctness.
>
>
> Thanks,
> Ming
>
> .
>

Patch
diff mbox series

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 75b926e..42f1475 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -208,7 +208,13 @@  static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, bool unbusy)
 	}
 	spin_lock_irqsave(q->queue_lock, flags);
 	blk_requeue_request(q, cmd->request);
-	kblockd_schedule_work(&device->requeue_work);
+	/*
+	 * need to get q_usage_counter which will be
+	 * put in scsi_requeue_run_queue.
+	 */
+	percpu_ref_get(&q->q_usage_counter);
+	if (!kblockd_schedule_work(&device->requeue_work))
+		percpu_ref_put(&q->q_usage_counter);
 	spin_unlock_irqrestore(q->queue_lock, flags);
 }

@@ -548,6 +554,11 @@  void scsi_requeue_run_queue(struct work_struct *work)
 	sdev = container_of(work, struct scsi_device, requeue_work);
 	q = sdev->request_queue;
 	scsi_run_queue(q);
+	/*
+	 * need to put q_usage_counter which is got in
+	 * scsi_end_request or __scsi_queue_insert.
+	 */
+	percpu_ref_put(&q->q_usage_counter);
 }

 /*
@@ -706,12 +717,13 @@  static bool scsi_end_request(struct request *req, blk_status_t error,
 		__blk_mq_end_request(req, error);

 		if (scsi_target(sdev)->single_lun ||
-		    !list_empty(&sdev->host->starved_list))
-			kblockd_schedule_work(&sdev->requeue_work);
-		else
+		    !list_empty(&sdev->host->starved_list)) {
+			if (!kblockd_schedule_work(&sdev->requeue_work))
+				percpu_ref_put(&q->q_usage_counter);
+		} else {
 			blk_mq_run_hw_queues(q, true);
-
-		percpu_ref_put(&q->q_usage_counter);
+			percpu_ref_put(&q->q_usage_counter);
+		}
 	} else {
 		unsigned long flags;

diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 3aee946..2dc422e 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -1392,7 +1392,8 @@  void __scsi_remove_device(struct scsi_device *sdev)
 	mutex_unlock(&sdev->state_mutex);

 	blk_cleanup_queue(sdev->request_queue);
-	cancel_work_sync(&sdev->requeue_work);
+	if (cancel_work_sync(&sdev->requeue_work))
+		percpu_ref_put(&sdev->request_queue->q_usage_counter);

 	if (sdev->host->hostt->slave_destroy)
 		sdev->host->hostt->slave_destroy(sdev);