diff mbox series

[net,1/2] iavf: Fix use-after-free in free_netdev

Message ID 20230408140030.5769-2-dinghui@sangfor.com.cn
State New
Headers
Series iavf: Fix issues when setting channels concurrency |

Commit Message

Ding Hui April 8, 2023, 2 p.m. UTC 
  We do netif_napi_add() for all allocated q_vectors[], but potentially
do netif_napi_del() for part of them, then kfree q_vectors and lefted
invalid pointers at dev->napi_list.

If num_active_queues is changed to less than allocated q_vectors[] by
by unexpected, when iavf_remove, we might see UAF in free_netdev like this:

[ 4093.900222] ==================================================================
[ 4093.900230] BUG: KASAN: use-after-free in free_netdev+0x308/0x390
[ 4093.900232] Read of size 8 at addr ffff88b4dc145640 by task test-iavf-1.sh/6699
[ 4093.900233]
[ 4093.900236] CPU: 10 PID: 6699 Comm: test-iavf-1.sh Kdump: loaded Tainted: G           O     --------- -t - 4.18.0 #1
[ 4093.900238] Hardware name: Powerleader PR2008AL/H12DSi-N6, BIOS 2.0 04/09/2021
[ 4093.900239] Call Trace:
[ 4093.900244]  dump_stack+0x71/0xab
[ 4093.900249]  print_address_description+0x6b/0x290
[ 4093.900251]  ? free_netdev+0x308/0x390
[ 4093.900252]  kasan_report+0x14a/0x2b0
[ 4093.900254]  free_netdev+0x308/0x390
[ 4093.900261]  iavf_remove+0x825/0xd20 [iavf]
[ 4093.900265]  pci_device_remove+0xa8/0x1f0
[ 4093.900268]  device_release_driver_internal+0x1c6/0x460
[ 4093.900271]  pci_stop_bus_device+0x101/0x150
[ 4093.900273]  pci_stop_and_remove_bus_device+0xe/0x20
[ 4093.900275]  pci_iov_remove_virtfn+0x187/0x420
[ 4093.900277]  ? pci_iov_add_virtfn+0xe10/0xe10
[ 4093.900278]  ? pci_get_subsys+0x90/0x90
[ 4093.900280]  sriov_disable+0xed/0x3e0
[ 4093.900282]  ? bus_find_device+0x12d/0x1a0
[ 4093.900290]  i40e_free_vfs+0x754/0x1210 [i40e]
[ 4093.900298]  ? i40e_reset_all_vfs+0x880/0x880 [i40e]
[ 4093.900299]  ? pci_get_device+0x7c/0x90
[ 4093.900300]  ? pci_get_subsys+0x90/0x90
[ 4093.900306]  ? pci_vfs_assigned.part.7+0x144/0x210
[ 4093.900309]  ? __mutex_lock_slowpath+0x10/0x10
[ 4093.900315]  i40e_pci_sriov_configure+0x1fa/0x2e0 [i40e]
[ 4093.900318]  sriov_numvfs_store+0x214/0x290
[ 4093.900320]  ? sriov_totalvfs_show+0x30/0x30
[ 4093.900321]  ? __mutex_lock_slowpath+0x10/0x10
[ 4093.900323]  ? __check_object_size+0x15a/0x350
[ 4093.900326]  kernfs_fop_write+0x280/0x3f0
[ 4093.900329]  vfs_write+0x145/0x440
[ 4093.900330]  ksys_write+0xab/0x160
[ 4093.900332]  ? __ia32_sys_read+0xb0/0xb0
[ 4093.900334]  ? fput_many+0x1a/0x120
[ 4093.900335]  ? filp_close+0xf0/0x130
[ 4093.900338]  do_syscall_64+0xa0/0x370
[ 4093.900339]  ? page_fault+0x8/0x30
[ 4093.900341]  entry_SYSCALL_64_after_hwframe+0x65/0xca
[ 4093.900357] RIP: 0033:0x7f16ad4d22c0
[ 4093.900359] Code: 73 01 c3 48 8b 0d d8 cb 2c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 83 3d 89 24 2d 00 00 75 10 b8 01 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 fe dd 01 00 48 89 04 24
[ 4093.900360] RSP: 002b:00007ffd6491b7f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[ 4093.900362] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f16ad4d22c0
[ 4093.900363] RDX: 0000000000000002 RSI: 0000000001a41408 RDI: 0000000000000001
[ 4093.900364] RBP: 0000000001a41408 R08: 00007f16ad7a1780 R09: 00007f16ae1f2700
[ 4093.900364] R10: 0000000000000001 R11: 0000000000000246 R12: 0000000000000002
[ 4093.900365] R13: 0000000000000001 R14: 00007f16ad7a0620 R15: 0000000000000001
[ 4093.900367]
[ 4093.900368] Allocated by task 820:
[ 4093.900371]  kasan_kmalloc+0xa6/0xd0
[ 4093.900373]  __kmalloc+0xfb/0x200
[ 4093.900376]  iavf_init_interrupt_scheme+0x63b/0x1320 [iavf]
[ 4093.900380]  iavf_watchdog_task+0x3d51/0x52c0 [iavf]
[ 4093.900382]  process_one_work+0x56a/0x11f0
[ 4093.900383]  worker_thread+0x8f/0xf40
[ 4093.900384]  kthread+0x2a0/0x390
[ 4093.900385]  ret_from_fork+0x1f/0x40
[ 4093.900387]  0xffffffffffffffff
[ 4093.900387]
[ 4093.900388] Freed by task 6699:
[ 4093.900390]  __kasan_slab_free+0x137/0x190
[ 4093.900391]  kfree+0x8b/0x1b0
[ 4093.900394]  iavf_free_q_vectors+0x11d/0x1a0 [iavf]
[ 4093.900397]  iavf_remove+0x35a/0xd20 [iavf]
[ 4093.900399]  pci_device_remove+0xa8/0x1f0
[ 4093.900400]  device_release_driver_internal+0x1c6/0x460
[ 4093.900401]  pci_stop_bus_device+0x101/0x150
[ 4093.900402]  pci_stop_and_remove_bus_device+0xe/0x20
[ 4093.900403]  pci_iov_remove_virtfn+0x187/0x420
[ 4093.900404]  sriov_disable+0xed/0x3e0
[ 4093.900409]  i40e_free_vfs+0x754/0x1210 [i40e]
[ 4093.900415]  i40e_pci_sriov_configure+0x1fa/0x2e0 [i40e]
[ 4093.900416]  sriov_numvfs_store+0x214/0x290
[ 4093.900417]  kernfs_fop_write+0x280/0x3f0
[ 4093.900418]  vfs_write+0x145/0x440
[ 4093.900419]  ksys_write+0xab/0x160
[ 4093.900420]  do_syscall_64+0xa0/0x370
[ 4093.900421]  entry_SYSCALL_64_after_hwframe+0x65/0xca
[ 4093.900422]  0xffffffffffffffff
[ 4093.900422]
[ 4093.900424] The buggy address belongs to the object at ffff88b4dc144200
                which belongs to the cache kmalloc-8k of size 8192
[ 4093.900425] The buggy address is located 5184 bytes inside of
                8192-byte region [ffff88b4dc144200, ffff88b4dc146200)
[ 4093.900425] The buggy address belongs to the page:
[ 4093.900427] page:ffffea00d3705000 refcount:1 mapcount:0 mapping:ffff88bf04415c80 index:0x0 compound_mapcount: 0
[ 4093.900430] flags: 0x10000000008100(slab|head)
[ 4093.900433] raw: 0010000000008100 dead000000000100 dead000000000200 ffff88bf04415c80
[ 4093.900434] raw: 0000000000000000 0000000000030003 00000001ffffffff 0000000000000000
[ 4093.900434] page dumped because: kasan: bad access detected
[ 4093.900435]
[ 4093.900435] Memory state around the buggy address:
[ 4093.900436]  ffff88b4dc145500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 4093.900437]  ffff88b4dc145580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 4093.900438] >ffff88b4dc145600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 4093.900438]                                            ^
[ 4093.900439]  ffff88b4dc145680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 4093.900440]  ffff88b4dc145700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[ 4093.900440] ==================================================================

Fix it by letting netif_napi_del() match to netif_napi_add().

Signed-off-by: Ding Hui <dinghui@sangfor.com.cn>
Cc: Donglin Peng <pengdonglin@sangfor.com.cn>
CC: Huang Cun <huangcun@sangfor.com.cn>
---
 drivers/net/ethernet/intel/iavf/iavf_main.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

Comments

Michal Kubiak April 18, 2023, 4:02 p.m. UTC | #1 
On Sat, Apr 08, 2023 at 10:00:29PM +0800, Ding Hui wrote:
> We do netif_napi_add() for all allocated q_vectors[], but potentially
> do netif_napi_del() for part of them, then kfree q_vectors and lefted
> invalid pointers at dev->napi_list.
> 
> If num_active_queues is changed to less than allocated q_vectors[] by
> by unexpected, when iavf_remove, we might see UAF in free_netdev like this:

Nitpick: the word "by" is accidentally doubled.

Also, I would recommend to add a description of reproduction steps (most
preferably a script or a command sequence) which triggers such an error
reported by KASAN.

> 
> [ 4093.900222] ==================================================================
> [ 4093.900230] BUG: KASAN: use-after-free in free_netdev+0x308/0x390
> [ 4093.900232] Read of size 8 at addr ffff88b4dc145640 by task test-iavf-1.sh/6699
> [ 4093.900233]
> [ 4093.900236] CPU: 10 PID: 6699 Comm: test-iavf-1.sh Kdump: loaded Tainted: G           O     --------- -t - 4.18.0 #1
> [ 4093.900238] Hardware name: Powerleader PR2008AL/H12DSi-N6, BIOS 2.0 04/09/2021
> [ 4093.900239] Call Trace:
> [ 4093.900244]  dump_stack+0x71/0xab
> [ 4093.900249]  print_address_description+0x6b/0x290
> [ 4093.900251]  ? free_netdev+0x308/0x390
> [ 4093.900252]  kasan_report+0x14a/0x2b0
> [ 4093.900254]  free_netdev+0x308/0x390
> [ 4093.900261]  iavf_remove+0x825/0xd20 [iavf]
> [ 4093.900265]  pci_device_remove+0xa8/0x1f0
> [ 4093.900268]  device_release_driver_internal+0x1c6/0x460
> [ 4093.900271]  pci_stop_bus_device+0x101/0x150
> [ 4093.900273]  pci_stop_and_remove_bus_device+0xe/0x20
> [ 4093.900275]  pci_iov_remove_virtfn+0x187/0x420
> [ 4093.900277]  ? pci_iov_add_virtfn+0xe10/0xe10
> [ 4093.900278]  ? pci_get_subsys+0x90/0x90
> [ 4093.900280]  sriov_disable+0xed/0x3e0
> [ 4093.900282]  ? bus_find_device+0x12d/0x1a0
> [ 4093.900290]  i40e_free_vfs+0x754/0x1210 [i40e]
> [ 4093.900298]  ? i40e_reset_all_vfs+0x880/0x880 [i40e]
> [ 4093.900299]  ? pci_get_device+0x7c/0x90
> [ 4093.900300]  ? pci_get_subsys+0x90/0x90
> [ 4093.900306]  ? pci_vfs_assigned.part.7+0x144/0x210
> [ 4093.900309]  ? __mutex_lock_slowpath+0x10/0x10
> [ 4093.900315]  i40e_pci_sriov_configure+0x1fa/0x2e0 [i40e]
> [ 4093.900318]  sriov_numvfs_store+0x214/0x290
> [ 4093.900320]  ? sriov_totalvfs_show+0x30/0x30
> [ 4093.900321]  ? __mutex_lock_slowpath+0x10/0x10
> [ 4093.900323]  ? __check_object_size+0x15a/0x350
> [ 4093.900326]  kernfs_fop_write+0x280/0x3f0
> [ 4093.900329]  vfs_write+0x145/0x440
> [ 4093.900330]  ksys_write+0xab/0x160
> [ 4093.900332]  ? __ia32_sys_read+0xb0/0xb0
> [ 4093.900334]  ? fput_many+0x1a/0x120
> [ 4093.900335]  ? filp_close+0xf0/0x130
> [ 4093.900338]  do_syscall_64+0xa0/0x370
> [ 4093.900339]  ? page_fault+0x8/0x30
> [ 4093.900341]  entry_SYSCALL_64_after_hwframe+0x65/0xca
> [ 4093.900357] RIP: 0033:0x7f16ad4d22c0
> ---
>  drivers/net/ethernet/intel/iavf/iavf_main.c | 6 +-----
>  1 file changed, 1 insertion(+), 5 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/iavf/iavf_main.c b/drivers/net/ethernet/intel/iavf/iavf_main.c
> index 095201e83c9d..a57e3425f960 100644
> --- a/drivers/net/ethernet/intel/iavf/iavf_main.c
> +++ b/drivers/net/ethernet/intel/iavf/iavf_main.c
> @@ -1849,19 +1849,15 @@ static int iavf_alloc_q_vectors(struct iavf_adapter *adapter)
>  static void iavf_free_q_vectors(struct iavf_adapter *adapter)
>  {
>  	int q_idx, num_q_vectors;
> -	int napi_vectors;
>  
>  	if (!adapter->q_vectors)
>  		return;
>  
>  	num_q_vectors = adapter->num_msix_vectors - NONQ_VECS;
> -	napi_vectors = adapter->num_active_queues;
>  
>  	for (q_idx = 0; q_idx < num_q_vectors; q_idx++) {
>  		struct iavf_q_vector *q_vector = &adapter->q_vectors[q_idx];
> -
> -		if (q_idx < napi_vectors)
> -			netif_napi_del(&q_vector->napi);
> +		netif_napi_del(&q_vector->napi);
>  	}
>  	kfree(adapter->q_vectors);
>  	adapter->q_vectors = NULL;

The fix looks correct to me.
We actually call "netif_napi_add()" for all allocated q_vectors unconditionally
in "iavf_alloc_q_vectors()").

Thanks,
Michal

> -- 
> 2.17.1
>
Michal Kubiak April 18, 2023, 4:08 p.m. UTC | #2 
On Tue, Apr 18, 2023 at 06:02:39PM +0200, Michal Kubiak wrote:
> Also, I would recommend to add a description of reproduction steps (most
> preferably a script or a command sequence) which triggers such an error
> reported by KASAN.

Oh, sorry. I have overlooked the scripts from the cover letter.
But still - maybe it will be a good idea to have them in the commit
message (to track them more easily using "git log")?

Michal
Tony Nguyen April 18, 2023, 4:50 p.m. UTC | #3 
On 4/8/2023 7:00 AM, Ding Hui wrote:
> We do netif_napi_add() for all allocated q_vectors[], but potentially
> do netif_napi_del() for part of them, then kfree q_vectors and lefted
> invalid pointers at dev->napi_list.
> 
> If num_active_queues is changed to less than allocated q_vectors[] by
> by unexpected, when iavf_remove, we might see UAF in free_netdev like this:
> 
> [ 4093.900222] ==================================================================
> [ 4093.900230] BUG: KASAN: use-after-free in free_netdev+0x308/0x390
> [ 4093.900232] Read of size 8 at addr ffff88b4dc145640 by task test-iavf-1.sh/6699

...

> Fix it by letting netif_napi_del() match to netif_napi_add().
> 

Should this have a Fixes:?

> Signed-off-by: Ding Hui <dinghui@sangfor.com.cn>
> Cc: Donglin Peng <pengdonglin@sangfor.com.cn>
> CC: Huang Cun <huangcun@sangfor.com.cn>
Ding Hui April 19, 2023, 12:50 a.m. UTC | #4 
On 2023/4/19 0:02, Michal Kubiak wrote:
> On Sat, Apr 08, 2023 at 10:00:29PM +0800, Ding Hui wrote:
>> We do netif_napi_add() for all allocated q_vectors[], but potentially
>> do netif_napi_del() for part of them, then kfree q_vectors and lefted
>> invalid pointers at dev->napi_list.
>>
>> If num_active_queues is changed to less than allocated q_vectors[] by
>> by unexpected, when iavf_remove, we might see UAF in free_netdev like this:
> 
> Nitpick: the word "by" is accidentally doubled.
> 

Oops, I noticed too, and I'll update in v2.

> Also, I would recommend to add a description of reproduction steps (most
> preferably a script or a command sequence) which triggers such an error
> reported by KASAN.
> 

Sure, I'll update in v2.

>>
>> [ 4093.900222] ==================================================================
>> [ 4093.900230] BUG: KASAN: use-after-free in free_netdev+0x308/0x390
>> [ 4093.900232] Read of size 8 at addr ffff88b4dc145640 by task test-iavf-1.sh/6699
>> [ 4093.900233]
>> [ 4093.900236] CPU: 10 PID: 6699 Comm: test-iavf-1.sh Kdump: loaded Tainted: G           O     --------- -t - 4.18.0 #1
>> [ 4093.900238] Hardware name: Powerleader PR2008AL/H12DSi-N6, BIOS 2.0 04/09/2021
>> [ 4093.900239] Call Trace:
>> [ 4093.900244]  dump_stack+0x71/0xab
>> [ 4093.900249]  print_address_description+0x6b/0x290
>> [ 4093.900251]  ? free_netdev+0x308/0x390
>> [ 4093.900252]  kasan_report+0x14a/0x2b0
>> [ 4093.900254]  free_netdev+0x308/0x390
>> [ 4093.900261]  iavf_remove+0x825/0xd20 [iavf]
>> [ 4093.900265]  pci_device_remove+0xa8/0x1f0
>> [ 4093.900268]  device_release_driver_internal+0x1c6/0x460
>> [ 4093.900271]  pci_stop_bus_device+0x101/0x150
>> [ 4093.900273]  pci_stop_and_remove_bus_device+0xe/0x20
>> [ 4093.900275]  pci_iov_remove_virtfn+0x187/0x420
>> [ 4093.900277]  ? pci_iov_add_virtfn+0xe10/0xe10
>> [ 4093.900278]  ? pci_get_subsys+0x90/0x90
>> [ 4093.900280]  sriov_disable+0xed/0x3e0
>> [ 4093.900282]  ? bus_find_device+0x12d/0x1a0
>> [ 4093.900290]  i40e_free_vfs+0x754/0x1210 [i40e]
>> [ 4093.900298]  ? i40e_reset_all_vfs+0x880/0x880 [i40e]
>> [ 4093.900299]  ? pci_get_device+0x7c/0x90
>> [ 4093.900300]  ? pci_get_subsys+0x90/0x90
>> [ 4093.900306]  ? pci_vfs_assigned.part.7+0x144/0x210
>> [ 4093.900309]  ? __mutex_lock_slowpath+0x10/0x10
>> [ 4093.900315]  i40e_pci_sriov_configure+0x1fa/0x2e0 [i40e]
>> [ 4093.900318]  sriov_numvfs_store+0x214/0x290
>> [ 4093.900320]  ? sriov_totalvfs_show+0x30/0x30
>> [ 4093.900321]  ? __mutex_lock_slowpath+0x10/0x10
>> [ 4093.900323]  ? __check_object_size+0x15a/0x350
>> [ 4093.900326]  kernfs_fop_write+0x280/0x3f0
>> [ 4093.900329]  vfs_write+0x145/0x440
>> [ 4093.900330]  ksys_write+0xab/0x160
>> [ 4093.900332]  ? __ia32_sys_read+0xb0/0xb0
>> [ 4093.900334]  ? fput_many+0x1a/0x120
>> [ 4093.900335]  ? filp_close+0xf0/0x130
>> [ 4093.900338]  do_syscall_64+0xa0/0x370
>> [ 4093.900339]  ? page_fault+0x8/0x30
>> [ 4093.900341]  entry_SYSCALL_64_after_hwframe+0x65/0xca
>> [ 4093.900357] RIP: 0033:0x7f16ad4d22c0
>> ---
>>   drivers/net/ethernet/intel/iavf/iavf_main.c | 6 +-----
>>   1 file changed, 1 insertion(+), 5 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/intel/iavf/iavf_main.c b/drivers/net/ethernet/intel/iavf/iavf_main.c
>> index 095201e83c9d..a57e3425f960 100644
>> --- a/drivers/net/ethernet/intel/iavf/iavf_main.c
>> +++ b/drivers/net/ethernet/intel/iavf/iavf_main.c
>> @@ -1849,19 +1849,15 @@ static int iavf_alloc_q_vectors(struct iavf_adapter *adapter)
>>   static void iavf_free_q_vectors(struct iavf_adapter *adapter)
>>   {
>>   	int q_idx, num_q_vectors;
>> -	int napi_vectors;
>>   
>>   	if (!adapter->q_vectors)
>>   		return;
>>   
>>   	num_q_vectors = adapter->num_msix_vectors - NONQ_VECS;
>> -	napi_vectors = adapter->num_active_queues;
>>   
>>   	for (q_idx = 0; q_idx < num_q_vectors; q_idx++) {
>>   		struct iavf_q_vector *q_vector = &adapter->q_vectors[q_idx];
>> -
>> -		if (q_idx < napi_vectors)
>> -			netif_napi_del(&q_vector->napi);
>> +		netif_napi_del(&q_vector->napi);
>>   	}
>>   	kfree(adapter->q_vectors);
>>   	adapter->q_vectors = NULL;
> 
> The fix looks correct to me.
> We actually call "netif_napi_add()" for all allocated q_vectors unconditionally
> in "iavf_alloc_q_vectors()").
> 

If you don't mind, I'll add Acked-by: tag in v2, thanks.

> Thanks,
> Michal
> 
>> -- 
>> 2.17.1
>>
>
Ding Hui April 19, 2023, 1 a.m. UTC | #5 
On 2023/4/19 0:50, Tony Nguyen wrote:
> On 4/8/2023 7:00 AM, Ding Hui wrote:
>> We do netif_napi_add() for all allocated q_vectors[], but potentially
>> do netif_napi_del() for part of them, then kfree q_vectors and lefted
>> invalid pointers at dev->napi_list.
>>
>> If num_active_queues is changed to less than allocated q_vectors[] by
>> by unexpected, when iavf_remove, we might see UAF in free_netdev like 
>> this:
>>
>> [ 4093.900222] 
>> ==================================================================
>> [ 4093.900230] BUG: KASAN: use-after-free in free_netdev+0x308/0x390
>> [ 4093.900232] Read of size 8 at addr ffff88b4dc145640 by task 
>> test-iavf-1.sh/6699
> 
> ...
> 
>> Fix it by letting netif_napi_del() match to netif_napi_add().
>>
> 
> Should this have a Fixes:?
> 

Yes, I searched the git log, and found that the mismatched usage was
introduced since the beginning of i40evf_main.c, so I'll add

Fixes: 5eae00c57f5e ("i40evf: main driver core")

in v2.
diff mbox series

Patch

diff --git a/drivers/net/ethernet/intel/iavf/iavf_main.c b/drivers/net/ethernet/intel/iavf/iavf_main.c
index 095201e83c9d..a57e3425f960 100644
--- a/drivers/net/ethernet/intel/iavf/iavf_main.c
+++ b/drivers/net/ethernet/intel/iavf/iavf_main.c
@@ -1849,19 +1849,15 @@  static int iavf_alloc_q_vectors(struct iavf_adapter *adapter)
 static void iavf_free_q_vectors(struct iavf_adapter *adapter)
 {
 	int q_idx, num_q_vectors;
-	int napi_vectors;
 
 	if (!adapter->q_vectors)
 		return;
 
 	num_q_vectors = adapter->num_msix_vectors - NONQ_VECS;
-	napi_vectors = adapter->num_active_queues;
 
 	for (q_idx = 0; q_idx < num_q_vectors; q_idx++) {
 		struct iavf_q_vector *q_vector = &adapter->q_vectors[q_idx];
-
-		if (q_idx < napi_vectors)
-			netif_napi_del(&q_vector->napi);
+		netif_napi_del(&q_vector->napi);
 	}
 	kfree(adapter->q_vectors);
 	adapter->q_vectors = NULL;