Re: [PATCH] iscsi-target: fix panic when add the second TCP connection to iSCSI session

[Feng Li]

Add lszhu@xxxxxxxx

2016-07-11 22:23 GMT+08:00 åå <lifeng1519@xxxxxxxxx>:
> This problem exists at least from v3.16.
> The upstream kernel still exists this issue.
>
> I have tested my patch and the following panic is disappeared.
>
> Thanks,
> - Alex
>
> #dmesg
>
> [ 1160.788676] sd 16:0:0:0: [sde] Attached SCSI disk
> [ 1383.962626] target_core_get_fabric() failed for usb_gadget
> [ 1404.788910] TARGET_CORE[iSCSI]: Unsupported SCSI Opcode 0x1b,
> sending CHECK_CONDITION.
> [ 1404.858451] BUG: unable to handle kernel NULL pointer dereference
> at 00000000000001f8
> [ 1404.858911] IP: [<ffffffffa05ee5d8>]
> iscsi_target_login_thread+0x728/0x10b0 [iscsi_target_mod]
> [ 1404.859746] PGD 230c29067 PUD 232060067 PMD 0
> [ 1404.859963] Oops: 0000 [#1] SMP
> [ 1404.860154] Modules linked in: crc32c_generic tcm_loop tcm_qla2xxx
> qla2xxx iscsi_target_mod ib_srpt vhost_scsi vhost tcm_fc libfc
> scsi_transport_fc scsi_tgt target_core_file target_core_iblock
> target_core_pscsi target_core_mod configfs nbd
> vmw_vsock_vmci_transport vsock bridge stp llc vmhgfs(O) snd_ens1371
> snd_rawmidi snd_seq_device snd_ac97_codec snd_pcm snd_timer snd
> vmw_balloon evdev soundcore ac97_bus gameport ppdev pcspkr sg psmouse
> serio_raw parport_pc vmwgfx parport battery ttm drm_kms_helper drm
> i2c_piix4 shpchp i2c_core vmw_vmci processor thermal_sys ac button
> binfmt_misc md_mod ib_iser rdma_cm iw_cm ib_cm ib_sa ib_mad ib_core
> ib_addr iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi
> hid_generic usbhid hid ext4 crc16 mbcache jbd2 sd_mod crc_t10dif
> crct10dif_generic crct10dif_common ata_generic
> [ 1404.861278]  mptspi scsi_transport_spi mptscsih ata_piix uhci_hcd
> ehci_pci ehci_hcd mptbase libata usbcore e1000 usb_common scsi_mod
> sunrpc dm_mirror dm_region_hash dm_log dm_mod autofs4
> [ 1404.861742] CPU: 2 PID: 1865 Comm: iscsi_np Tainted: G           O
> 3.16.0-4-amd64 #1 Debian 3.16.7-ckt25-1
> [ 1404.861868] Hardware name: VMware, Inc. VMware Virtual
> Platform/440BX Desktop Reference Platform, BIOS 6.00 07/02/2015
> [ 1404.862033] task: ffff880234c849a0 ti: ffff8800b9c20000 task.ti:
> ffff8800b9c20000
> [ 1404.862114] RIP: 0010:[<ffffffffa05ee5d8>]  [<ffffffffa05ee5d8>]
> iscsi_target_login_thread+0x728/0x10b0 [iscsi_target_mod]
> [ 1404.862233] RSP: 0018:ffff8800b9c23e60  EFLAGS: 00010246
> [ 1404.862282] RAX: 0000000000000000 RBX: ffff88023125b800 RCX: ffff8802b4d8d000
> [ 1404.862344] RDX: 000000000000002d RSI: 00000000fffffe01 RDI: ffff880233ef1800
> [ 1404.862406] RBP: ffff8800b9651a00 R08: 00000000d5a073de R09: ffff88023487e6c0
> [ 1404.862585] R10: 00000000ead0c2e5 R11: 00000000d039ef6a R12: ffff88023125b854
> [ 1404.865580] R13: ffff88023125b908 R14: ffff880233ef1800 R15: ffff880234c849a0
> [ 1404.867732] FS:  00007fba67e2fb80(0000) GS:ffff88023e640000(0000)
> knlGS:0000000000000000
> [ 1404.869772] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
> [ 1404.871850] CR2: 00000000000001f8 CR3: 0000000230ffa000 CR4: 00000000000007e0
> [ 1404.874271] Stack:
> [ 1404.877492]  ffff88023125b908 00ff880234c849a0 ffff88023125b858
> ffff88023481f400
> [ 1404.880162]  ffffffff81510d00 ffff880230768000 ffff8800b9c23fd8
> 0000000000012f00
> [ 1404.883545]  ffff880234c849a0 ffff880233e9da40 ffff88023125b800
> ffffffffa05edeb0
> [ 1404.885865] Call Trace:
> [ 1404.888384]  [<ffffffff81510d00>] ? __schedule+0x250/0x700
> [ 1404.890619]  [<ffffffffa05edeb0>] ?
> iscsi_target_login_sess_out+0x240/0x240 [iscsi_target_mod]
> [ 1404.892668]  [<ffffffff8108809d>] ? kthread+0xbd/0xe0
> [ 1404.894646]  [<ffffffff81087fe0>] ? kthread_create_on_node+0x180/0x180
> [ 1404.896553]  [<ffffffff81514958>] ? ret_from_fork+0x58/0x90
> [ 1404.898556]  [<ffffffff81087fe0>] ? kthread_create_on_node+0x180/0x180
> [ 1404.900597] Code: 09 00 00 48 89 ea 4c 89 f6 48 89 df e8 52 1b 00
> 00 85 c0 0f 88 82 02 00 00 0f b6 44 24 0f 4c 89 f7 88 45 09 49 8b 86
> d8 04 00 00 <4c> 8b a8 f8 01 00 00 49 8b 86 a0 04 00 00 ff 90 98 00 00
> 00 41
> [ 1404.906962] RIP  [<ffffffffa05ee5d8>]
> iscsi_target_login_thread+0x728/0x10b0 [iscsi_target_mod]
> [ 1404.908962]  RSP <ffff8800b9c23e60>
> [ 1404.910940] CR2: 00000000000001f8
> [ 1404.917670] ---[ end trace d29d8c681ab2bdfb ]---
> [ 1419.859690] iSCSI Login timeout on Network Portal 10.182.70.69:3260
> [ 1479.832056] iSCSI Login timeout on Network Portal 10.182.70.68:3260
> [ 1479.835739] iSCSI Login negotiation failed.
> [ 1549.332632] iSCSI Login timeout on Network Portal 10.182.70.68:3260
> [ 1549.338432] iSCSI Login negotiation failed.
> [ 1564.358423] iSCSI Login timeout on Network Portal 10.182.70.68:3260
> [ 1564.362443] iSCSI Login negotiation failed.
>
> 2016-07-12 6:15 GMT+08:00 Feng Li <li.feng@xxxxxxxxxx>:
>> From: Feng Li <lifeng1519@xxxxxxxxx>
>>
>> In MC/S scenario, the conn->sess has been set NULL in
>> iscsi_login_non_zero_tsih_s1 when the second connection comes here,
>> then kernel panic.
>>
>> The conn->sess will be assigned in iscsi_login_non_zero_tsih_s2. So
>> we should check whether it's NULL before calling.
>>
>> Signed-off-by: Feng Li <lifeng1519@xxxxxxxxx>
>> ---
>>  drivers/target/iscsi/iscsi_target_login.c | 5 +++--
>>  1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/target/iscsi/iscsi_target_login.c b/drivers/target/iscsi/iscsi_target_login.c
>> index b5212f0..adf419f 100644
>> --- a/drivers/target/iscsi/iscsi_target_login.c
>> +++ b/drivers/target/iscsi/iscsi_target_login.c
>> @@ -1371,8 +1371,9 @@ static int __iscsi_target_login_thread(struct iscsi_np *np)
>>         }
>>         login->zero_tsih = zero_tsih;
>>
>> -       conn->sess->se_sess->sup_prot_ops =
>> -               conn->conn_transport->iscsit_get_sup_prot_ops(conn);
>> +       if (conn->sess)
>> +               conn->sess->se_sess->sup_prot_ops =
>> +                       conn->conn_transport->iscsit_get_sup_prot_ops(conn);
>>
>>         tpg = conn->tpg;
>>         if (!tpg) {
>> --
>> 2.9.0
>>
>
>
>
> --
> Thanks and Best Regards,
> Feng Li(Alex)



-- 
Thanks and Best Regards,
Feng Li(Alex)