diff mbox series

[v2] scsi: libsas: stop discovering if oob mode is disconnected

Message ID 20191205114144.39640-1-yanaijie@huawei.com (mailing list archive)
State Superseded
Headers show
Series [v2] scsi: libsas: stop discovering if oob mode is disconnected | expand

Commit Message

Jason Yan Dec. 5, 2019, 11:41 a.m. UTC
The discovering of sas port is driving by workqueue in libsas. When
libsas is processing port events or phy events in workqueue, new evnets
may rise up and change the state of some structures such as asd_sas_phy.
This may cause some problems such as follows:

==>thread 1                       ==>thread 2

                                  ==>phy up
                                  ==>phy_up_v3_hw()
                                    ==>oob_mode = SATA_OOB_MODE;
                                  ==>phy donw quickly
                                  ==>hisi_sas_phy_down()
                                    ==>sas_ha->notify_phy_event()
                                    ==>sas_phy_disconnected()
                                      ==>oob_mode = OOB_NOT_CONNECTED
==>workqueue wakeup
==>sas_form_port()
  ==>sas_discover_domain()
    ==>sas_get_port_device()
      ==>oob_mode is OOB_NOT_CONNECTED and device
         is wrongly taken as expander

This at last lead to the panic when libsas trying to issue a command to
discover the device.

[183047.614035] Unable to handle kernel NULL pointer dereference at
virtual address 0000000000000058
[183047.622896] Mem abort info:
[183047.625762]   ESR = 0x96000004
[183047.628893]   Exception class = DABT (current EL), IL = 32 bits
[183047.634888]   SET = 0, FnV = 0
[183047.638015]   EA = 0, S1PTW = 0
[183047.641232] Data abort info:
[183047.644189]   ISV = 0, ISS = 0x00000004
[183047.648100]   CM = 0, WnR = 0
[183047.651145] user pgtable: 4k pages, 48-bit VAs, pgdp =
00000000b7df67be
[183047.657834] [0000000000000058] pgd=0000000000000000
[183047.662789] Internal error: Oops: 96000004 [#1] SMP
[183047.667740] Process kworker/u16:2 (pid: 31291, stack limit =
0x00000000417c4974)
[183047.675208] CPU: 0 PID: 3291 Comm: kworker/u16:2 Tainted: G
W  OE 4.19.36-vhulk1907.1.0.h410.eulerosv2r8.aarch64 #1
[183047.687015] Hardware name: N/A N/A/Kunpeng Desktop Board D920S10,
BIOS 0.15 10/22/2019
[183047.695007] Workqueue: 0000:74:02.0_disco_q sas_discover_domain
[183047.700999] pstate: 20c00009 (nzCv daif +PAN +UAO)
[183047.705864] pc : prep_ata_v3_hw+0xf8/0x230 [hisi_sas_v3_hw]
[183047.711510] lr : prep_ata_v3_hw+0xb0/0x230 [hisi_sas_v3_hw]
[183047.717153] sp : ffff00000f28ba60
[183047.720541] x29: ffff00000f28ba60 x28: ffff8026852d7228
[183047.725925] x27: ffff8027dba3e0a8 x26: ffff8027c05fc200
[183047.731310] x25: 0000000000000000 x24: ffff8026bafa8dc0
[183047.736695] x23: ffff8027c05fc218 x22: ffff8026852d7228
[183047.742079] x21: ffff80007c2f2940 x20: ffff8027c05fc200
[183047.747464] x19: 0000000000f80800 x18: 0000000000000010
[183047.752848] x17: 0000000000000000 x16: 0000000000000000
[183047.758232] x15: ffff000089a5a4ff x14: 0000000000000005
[183047.763617] x13: ffff000009a5a50e x12: ffff8026bafa1e20
[183047.769001] x11: ffff0000087453b8 x10: ffff00000f28b870
[183047.774385] x9 : 0000000000000000 x8 : ffff80007e58f9b0
[183047.779770] x7 : 0000000000000000 x6 : 000000000000003f
[183047.785154] x5 : 0000000000000040 x4 : ffffffffffffffe0
[183047.790538] x3 : 00000000000000f8 x2 : 0000000002000007
[183047.795922] x1 : 0000000000000008 x0 : 0000000000000000
[183047.801307] Call trace:
[183047.803827]  prep_ata_v3_hw+0xf8/0x230 [hisi_sas_v3_hw]
[183047.809127]  hisi_sas_task_prep+0x750/0x888 [hisi_sas_main]
[183047.814773]  hisi_sas_task_exec.isra.7+0x88/0x1f0 [hisi_sas_main]
[183047.820939]  hisi_sas_queue_command+0x28/0x38 [hisi_sas_main]
[183047.826757]  smp_execute_task_sg+0xec/0x218
[183047.831013]  smp_execute_task+0x74/0xa0
[183047.834921]  sas_discover_expander.part.7+0x9c/0x5f8
[183047.839959]  sas_discover_root_expander+0x90/0x160
[183047.844822]  sas_discover_domain+0x1b8/0x1e8
[183047.849164]  process_one_work+0x1b4/0x3f8
[183047.853246]  worker_thread+0x54/0x470
[183047.856981]  kthread+0x134/0x138
[183047.860283]  ret_from_fork+0x10/0x18
[183047.863931] Code: f9407a80 528000e2 39409281 72a04002 (b9405800)
[183047.870097] kernel fault(0x1) notification starting on CPU 0
[183047.875828] kernel fault(0x1) notification finished on CPU 0
[183047.881559] Modules linked in: unibsp(OE) hns3(OE) hclge(OE)
hnae3(OE) mem_drv(OE) hisi_sas_v3_hw(OE) hisi_sas_main(OE)
[183047.892418] ---[ end trace 4cc26083fc11b783  ]---
[183047.897107] Kernel panic - not syncing: Fatal exception
[183047.902403] kernel fault(0x5) notification starting on CPU 0
[183047.908134] kernel fault(0x5) notification finished on CPU 0
[183047.913865] SMP: stopping secondary CPUs
[183047.917861] Kernel Offset: disabled
[183047.921422] CPU features: 0x2,a2a00a38
[183047.925243] Memory Limit: none
[183047.928372] kernel reboot(0x2) notification starting on CPU 0
[183047.934190] kernel reboot(0x2) notification finished on CPU 0
[183047.940008] ---[ end Kernel panic - not syncing: Fatal exception
]---

Fixes: 2908d778ab3e ("[SCSI] aic94xx: new driver")
Reported-by: Gao Chuan <gaochuan4@huawei.com>
Signed-off-by: Jason Yan <yanaijie@huawei.com>
---
 drivers/scsi/libsas/sas_discover.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

Comments

John Garry Dec. 5, 2019, 11:36 a.m. UTC | #1
On 05/12/2019 11:41, yanaijie wrote:
> The discovering of sas port is driving by workqueue in libsas. When

/s/driving/driven/

> libsas is processing port events or phy events in workqueue, new evnets

again,
/s/evnets/events/

> may rise up and change the state of some structures such as asd_sas_phy.
> This may cause some problems such as follows:
> 
> ==>thread 1                       ==>thread 2
> 
>                                    ==>phy up
>                                    ==>phy_up_v3_hw()
>                                      ==>oob_mode = SATA_OOB_MODE;
>                                    ==>phy donw quickly

and again,

/s/donw/down/

>                                    ==>hisi_sas_phy_down()
>                                      ==>sas_ha->notify_phy_event()
>                                      ==>sas_phy_disconnected()
>                                        ==>oob_mode = OOB_NOT_CONNECTED
> ==>workqueue wakeup
> ==>sas_form_port()
>    ==>sas_discover_domain()
>      ==>sas_get_port_device()
>        ==>oob_mode is OOB_NOT_CONNECTED and device
>           is wrongly taken as expander
> 
> This at last lead to the panic when libsas trying to issue a command to
> discover the device.
> 
> [183047.614035] Unable to handle kernel NULL pointer dereference at
> virtual address 0000000000000058
> [183047.622896] Mem abort info:
> [183047.625762]   ESR = 0x96000004
> [183047.628893]   Exception class = DABT (current EL), IL = 32 bits
> [183047.634888]   SET = 0, FnV = 0
> [183047.638015]   EA = 0, S1PTW = 0
> [183047.641232] Data abort info:
> [183047.644189]   ISV = 0, ISS = 0x00000004
> [183047.648100]   CM = 0, WnR = 0
> [183047.651145] user pgtable: 4k pages, 48-bit VAs, pgdp =
> 00000000b7df67be
> [183047.657834] [0000000000000058] pgd=0000000000000000
> [183047.662789] Internal error: Oops: 96000004 [#1] SMP
> [183047.667740] Process kworker/u16:2 (pid: 31291, stack limit =
> 0x00000000417c4974)
> [183047.675208] CPU: 0 PID: 3291 Comm: kworker/u16:2 Tainted: G
> W  OE 4.19.36-vhulk1907.1.0.h410.eulerosv2r8.aarch64 #1
> [183047.687015] Hardware name: N/A N/A/Kunpeng Desktop Board D920S10,
> BIOS 0.15 10/22/2019
> [183047.695007] Workqueue: 0000:74:02.0_disco_q sas_discover_domain
> [183047.700999] pstate: 20c00009 (nzCv daif +PAN +UAO)
> [183047.705864] pc : prep_ata_v3_hw+0xf8/0x230 [hisi_sas_v3_hw]
> [183047.711510] lr : prep_ata_v3_hw+0xb0/0x230 [hisi_sas_v3_hw]
> [183047.717153] sp : ffff00000f28ba60
> [183047.720541] x29: ffff00000f28ba60 x28: ffff8026852d7228
> [183047.725925] x27: ffff8027dba3e0a8 x26: ffff8027c05fc200
> [183047.731310] x25: 0000000000000000 x24: ffff8026bafa8dc0
> [183047.736695] x23: ffff8027c05fc218 x22: ffff8026852d7228
> [183047.742079] x21: ffff80007c2f2940 x20: ffff8027c05fc200
> [183047.747464] x19: 0000000000f80800 x18: 0000000000000010
> [183047.752848] x17: 0000000000000000 x16: 0000000000000000
> [183047.758232] x15: ffff000089a5a4ff x14: 0000000000000005
> [183047.763617] x13: ffff000009a5a50e x12: ffff8026bafa1e20
> [183047.769001] x11: ffff0000087453b8 x10: ffff00000f28b870
> [183047.774385] x9 : 0000000000000000 x8 : ffff80007e58f9b0
> [183047.779770] x7 : 0000000000000000 x6 : 000000000000003f
> [183047.785154] x5 : 0000000000000040 x4 : ffffffffffffffe0
> [183047.790538] x3 : 00000000000000f8 x2 : 0000000002000007
> [183047.795922] x1 : 0000000000000008 x0 : 0000000000000000
> [183047.801307] Call trace:
> [183047.803827]  prep_ata_v3_hw+0xf8/0x230 [hisi_sas_v3_hw]
> [183047.809127]  hisi_sas_task_prep+0x750/0x888 [hisi_sas_main]
> [183047.814773]  hisi_sas_task_exec.isra.7+0x88/0x1f0 [hisi_sas_main]
> [183047.820939]  hisi_sas_queue_command+0x28/0x38 [hisi_sas_main]
> [183047.826757]  smp_execute_task_sg+0xec/0x218
> [183047.831013]  smp_execute_task+0x74/0xa0
> [183047.834921]  sas_discover_expander.part.7+0x9c/0x5f8
> [183047.839959]  sas_discover_root_expander+0x90/0x160
> [183047.844822]  sas_discover_domain+0x1b8/0x1e8
> [183047.849164]  process_one_work+0x1b4/0x3f8
> [183047.853246]  worker_thread+0x54/0x470
> [183047.856981]  kthread+0x134/0x138
> [183047.860283]  ret_from_fork+0x10/0x18
> [183047.863931] Code: f9407a80 528000e2 39409281 72a04002 (b9405800)
> [183047.870097] kernel fault(0x1) notification starting on CPU 0
> [183047.875828] kernel fault(0x1) notification finished on CPU 0
> [183047.881559] Modules linked in: unibsp(OE) hns3(OE) hclge(OE)
> hnae3(OE) mem_drv(OE) hisi_sas_v3_hw(OE) hisi_sas_main(OE)
> [183047.892418] ---[ end trace 4cc26083fc11b783  ]---
> [183047.897107] Kernel panic - not syncing: Fatal exception
> [183047.902403] kernel fault(0x5) notification starting on CPU 0
> [183047.908134] kernel fault(0x5) notification finished on CPU 0
> [183047.913865] SMP: stopping secondary CPUs
> [183047.917861] Kernel Offset: disabled
> [183047.921422] CPU features: 0x2,a2a00a38
> [183047.925243] Memory Limit: none
> [183047.928372] kernel reboot(0x2) notification starting on CPU 0
> [183047.934190] kernel reboot(0x2) notification finished on CPU 0
> [183047.940008] ---[ end Kernel panic - not syncing: Fatal exception
> ]---
> 
> Fixes: 2908d778ab3e ("[SCSI] aic94xx: new driver")
> Reported-by: Gao Chuan <gaochuan4@huawei.com>
> Signed-off-by: Jason Yan <yanaijie@huawei.com>

Apart from typos:
Reviewed-by: John Garry <john.garry@huawei.com>

> ---
>   drivers/scsi/libsas/sas_discover.c | 11 ++++++++++-
>   1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/scsi/libsas/sas_discover.c b/drivers/scsi/libsas/sas_discover.c
> index f47b4b281b14..cb5d40d963e3 100644
> --- a/drivers/scsi/libsas/sas_discover.c
> +++ b/drivers/scsi/libsas/sas_discover.c
> @@ -81,12 +81,21 @@ static int sas_get_port_device(struct asd_sas_port *port)
>   		else
>   			dev->dev_type = SAS_SATA_DEV;
>   		dev->tproto = SAS_PROTOCOL_SATA;
> -	} else {
> +	} else if (port->oob_mode == SAS_OOB_MODE) {
>   		struct sas_identify_frame *id =
>   			(struct sas_identify_frame *) dev->frame_rcvd;
>   		dev->dev_type = id->dev_type;
>   		dev->iproto = id->initiator_bits;
>   		dev->tproto = id->target_bits;
> +	} else {
> +		/* If the oob mode is OOB_NOT_CONNECTED, the port is
> +		 * disconnected due to race with PHY down. We cannot
> +		 * continue to discover this port
> +		 */
> +		sas_put_device(dev);
> +		pr_warn("Port %16llx is disconnected when discovering\n",
> +			SAS_ADDR(port->attached_sas_addr));

note: there seems to be an inconsistency in libsas in format specifiers 
for printing a SAS address. We have a mix of %16llx, %llx, %016llx.

And then we have something like pm8001_ctl_host_sas_address_show(), 
which uses 0x%016llx, and not SAS_ADDR() macro.

Maybe we can tidy all that up separately.

Thanks

> +		return -ENODEV;
>   	}
>   
>   	sas_init_dev(dev);
>
Jason Yan Dec. 6, 2019, 12:40 a.m. UTC | #2
在 2019/12/5 19:36, John Garry 写道:
> On 05/12/2019 11:41, yanaijie wrote:
>> The discovering of sas port is driving by workqueue in libsas. When
> 
> /s/driving/driven/
> 

Oh, sorry I forgot to change these typos. I will fix these right now.


>> libsas is processing port events or phy events in workqueue, new evnets
> 
> again,
> /s/evnets/events/
> 
>> may rise up and change the state of some structures such as asd_sas_phy.
>> This may cause some problems such as follows:
>>
>> ==>thread 1                       ==>thread 2
>>
>>                                    ==>phy up
>>                                    ==>phy_up_v3_hw()
>>                                      ==>oob_mode = SATA_OOB_MODE;
>>                                    ==>phy donw quickly
> 
> and again,
> 
> /s/donw/down/
> 
>>                                    ==>hisi_sas_phy_down()
>>                                      ==>sas_ha->notify_phy_event()
>>                                      ==>sas_phy_disconnected()
>>                                        ==>oob_mode = OOB_NOT_CONNECTED
>> ==>workqueue wakeup
>> ==>sas_form_port()
>>    ==>sas_discover_domain()
>>      ==>sas_get_port_device()
>>        ==>oob_mode is OOB_NOT_CONNECTED and device
>>           is wrongly taken as expander
>>
>> This at last lead to the panic when libsas trying to issue a command to
>> discover the device.
>>
>> [183047.614035] Unable to handle kernel NULL pointer dereference at
>> virtual address 0000000000000058
>> [183047.622896] Mem abort info:
>> [183047.625762]   ESR = 0x96000004
>> [183047.628893]   Exception class = DABT (current EL), IL = 32 bits
>> [183047.634888]   SET = 0, FnV = 0
>> [183047.638015]   EA = 0, S1PTW = 0
>> [183047.641232] Data abort info:
>> [183047.644189]   ISV = 0, ISS = 0x00000004
>> [183047.648100]   CM = 0, WnR = 0
>> [183047.651145] user pgtable: 4k pages, 48-bit VAs, pgdp =
>> 00000000b7df67be
>> [183047.657834] [0000000000000058] pgd=0000000000000000
>> [183047.662789] Internal error: Oops: 96000004 [#1] SMP
>> [183047.667740] Process kworker/u16:2 (pid: 31291, stack limit =
>> 0x00000000417c4974)
>> [183047.675208] CPU: 0 PID: 3291 Comm: kworker/u16:2 Tainted: G
>> W  OE 4.19.36-vhulk1907.1.0.h410.eulerosv2r8.aarch64 #1
>> [183047.687015] Hardware name: N/A N/A/Kunpeng Desktop Board D920S10,
>> BIOS 0.15 10/22/2019
>> [183047.695007] Workqueue: 0000:74:02.0_disco_q sas_discover_domain
>> [183047.700999] pstate: 20c00009 (nzCv daif +PAN +UAO)
>> [183047.705864] pc : prep_ata_v3_hw+0xf8/0x230 [hisi_sas_v3_hw]
>> [183047.711510] lr : prep_ata_v3_hw+0xb0/0x230 [hisi_sas_v3_hw]
>> [183047.717153] sp : ffff00000f28ba60
>> [183047.720541] x29: ffff00000f28ba60 x28: ffff8026852d7228
>> [183047.725925] x27: ffff8027dba3e0a8 x26: ffff8027c05fc200
>> [183047.731310] x25: 0000000000000000 x24: ffff8026bafa8dc0
>> [183047.736695] x23: ffff8027c05fc218 x22: ffff8026852d7228
>> [183047.742079] x21: ffff80007c2f2940 x20: ffff8027c05fc200
>> [183047.747464] x19: 0000000000f80800 x18: 0000000000000010
>> [183047.752848] x17: 0000000000000000 x16: 0000000000000000
>> [183047.758232] x15: ffff000089a5a4ff x14: 0000000000000005
>> [183047.763617] x13: ffff000009a5a50e x12: ffff8026bafa1e20
>> [183047.769001] x11: ffff0000087453b8 x10: ffff00000f28b870
>> [183047.774385] x9 : 0000000000000000 x8 : ffff80007e58f9b0
>> [183047.779770] x7 : 0000000000000000 x6 : 000000000000003f
>> [183047.785154] x5 : 0000000000000040 x4 : ffffffffffffffe0
>> [183047.790538] x3 : 00000000000000f8 x2 : 0000000002000007
>> [183047.795922] x1 : 0000000000000008 x0 : 0000000000000000
>> [183047.801307] Call trace:
>> [183047.803827]  prep_ata_v3_hw+0xf8/0x230 [hisi_sas_v3_hw]
>> [183047.809127]  hisi_sas_task_prep+0x750/0x888 [hisi_sas_main]
>> [183047.814773]  hisi_sas_task_exec.isra.7+0x88/0x1f0 [hisi_sas_main]
>> [183047.820939]  hisi_sas_queue_command+0x28/0x38 [hisi_sas_main]
>> [183047.826757]  smp_execute_task_sg+0xec/0x218
>> [183047.831013]  smp_execute_task+0x74/0xa0
>> [183047.834921]  sas_discover_expander.part.7+0x9c/0x5f8
>> [183047.839959]  sas_discover_root_expander+0x90/0x160
>> [183047.844822]  sas_discover_domain+0x1b8/0x1e8
>> [183047.849164]  process_one_work+0x1b4/0x3f8
>> [183047.853246]  worker_thread+0x54/0x470
>> [183047.856981]  kthread+0x134/0x138
>> [183047.860283]  ret_from_fork+0x10/0x18
>> [183047.863931] Code: f9407a80 528000e2 39409281 72a04002 (b9405800)
>> [183047.870097] kernel fault(0x1) notification starting on CPU 0
>> [183047.875828] kernel fault(0x1) notification finished on CPU 0
>> [183047.881559] Modules linked in: unibsp(OE) hns3(OE) hclge(OE)
>> hnae3(OE) mem_drv(OE) hisi_sas_v3_hw(OE) hisi_sas_main(OE)
>> [183047.892418] ---[ end trace 4cc26083fc11b783  ]---
>> [183047.897107] Kernel panic - not syncing: Fatal exception
>> [183047.902403] kernel fault(0x5) notification starting on CPU 0
>> [183047.908134] kernel fault(0x5) notification finished on CPU 0
>> [183047.913865] SMP: stopping secondary CPUs
>> [183047.917861] Kernel Offset: disabled
>> [183047.921422] CPU features: 0x2,a2a00a38
>> [183047.925243] Memory Limit: none
>> [183047.928372] kernel reboot(0x2) notification starting on CPU 0
>> [183047.934190] kernel reboot(0x2) notification finished on CPU 0
>> [183047.940008] ---[ end Kernel panic - not syncing: Fatal exception
>> ]---
>>
>> Fixes: 2908d778ab3e ("[SCSI] aic94xx: new driver")
>> Reported-by: Gao Chuan <gaochuan4@huawei.com>
>> Signed-off-by: Jason Yan <yanaijie@huawei.com>
> 
> Apart from typos:
> Reviewed-by: John Garry <john.garry@huawei.com>
> 

Thanks.

>> ---
>>   drivers/scsi/libsas/sas_discover.c | 11 ++++++++++-
>>   1 file changed, 10 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/scsi/libsas/sas_discover.c 
>> b/drivers/scsi/libsas/sas_discover.c
>> index f47b4b281b14..cb5d40d963e3 100644
>> --- a/drivers/scsi/libsas/sas_discover.c
>> +++ b/drivers/scsi/libsas/sas_discover.c
>> @@ -81,12 +81,21 @@ static int sas_get_port_device(struct asd_sas_port 
>> *port)
>>           else
>>               dev->dev_type = SAS_SATA_DEV;
>>           dev->tproto = SAS_PROTOCOL_SATA;
>> -    } else {
>> +    } else if (port->oob_mode == SAS_OOB_MODE) {
>>           struct sas_identify_frame *id =
>>               (struct sas_identify_frame *) dev->frame_rcvd;
>>           dev->dev_type = id->dev_type;
>>           dev->iproto = id->initiator_bits;
>>           dev->tproto = id->target_bits;
>> +    } else {
>> +        /* If the oob mode is OOB_NOT_CONNECTED, the port is
>> +         * disconnected due to race with PHY down. We cannot
>> +         * continue to discover this port
>> +         */
>> +        sas_put_device(dev);
>> +        pr_warn("Port %16llx is disconnected when discovering\n",
>> +            SAS_ADDR(port->attached_sas_addr));
> 
> note: there seems to be an inconsistency in libsas in format specifiers 
> for printing a SAS address. We have a mix of %16llx, %llx, %016llx.
> 
> And then we have something like pm8001_ctl_host_sas_address_show(), 
> which uses 0x%016llx, and not SAS_ADDR() macro.
> 
> Maybe we can tidy all that up separately.
> 

Agree.

> Thanks
> 
>> +        return -ENODEV;
>>       }
>>       sas_init_dev(dev);
>>
> 
> 
> .
diff mbox series

Patch

diff --git a/drivers/scsi/libsas/sas_discover.c b/drivers/scsi/libsas/sas_discover.c
index f47b4b281b14..cb5d40d963e3 100644
--- a/drivers/scsi/libsas/sas_discover.c
+++ b/drivers/scsi/libsas/sas_discover.c
@@ -81,12 +81,21 @@  static int sas_get_port_device(struct asd_sas_port *port)
 		else
 			dev->dev_type = SAS_SATA_DEV;
 		dev->tproto = SAS_PROTOCOL_SATA;
-	} else {
+	} else if (port->oob_mode == SAS_OOB_MODE) {
 		struct sas_identify_frame *id =
 			(struct sas_identify_frame *) dev->frame_rcvd;
 		dev->dev_type = id->dev_type;
 		dev->iproto = id->initiator_bits;
 		dev->tproto = id->target_bits;
+	} else {
+		/* If the oob mode is OOB_NOT_CONNECTED, the port is
+		 * disconnected due to race with PHY down. We cannot
+		 * continue to discover this port
+		 */
+		sas_put_device(dev);
+		pr_warn("Port %16llx is disconnected when discovering\n",
+			SAS_ADDR(port->attached_sas_addr));
+		return -ENODEV;
 	}
 
 	sas_init_dev(dev);