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

From: Feng Li
Date: Sun Jul 17 2016 - 22:20:30 EST


Hi Sumit,

I have tested and the oops is disappeared.

Could you double check if you have patched successfully?
This stack is still the same.

The place is 0x00000000000001f8.

gdb> p (int)&((struct iscsi_session*)0)->se_sess
$3 = 0x1f8

2016-07-14 17:59 GMT+08:00 Sumit Rai <sumit.rai@xxxxxxxxxxxxxx>:
> Thanks for the patch Feng, I have tested this patch and below panic has also disappeared.
> (initially reported at http://article.gmane.org/gmane.linux.scsi.target.devel/12735).
>
> dmesg
> =====
> [ 862.784477] BUG: unable to handle kernel NULL pointer dereference at 00000000000001f8
> [ 862.784486] IP: [<ffffffffc0604b44>] iscsi_target_login_thread+0x724/0xfa0 [iscsi_target_mod]
> [ 862.784570] PGD 0
> [ 862.784572] Oops: 0000 [#1] SMP
> [ 862.784575] Modules linked in: target_core_user uio tcm_fc libfc ib_srpt tcm_usb_gadget
> libcomposite udc_core tcm_loop vhost_scsi vhost iscsi_target_mod tcm_qla2xxx qla2xxx
> scsi_transport_fc target_core_file target_core_iblock target_core_pscsi target_core_mod
> configfs pci_stub vboxpci(OE) vboxnetadp(OE) vboxnetflt(OE) vboxdrv(OE)
> vmw_vsock_vmci_transport vsock vmhgfs(OE) coretemp kvm_intel kvm binfmt_misc irqbypass
> crct10dif_pclmul crc32_pclmul aesni_intel vmw_balloon aes_x86_64 lrw gf128mul glue_helper
> ablk_helper cryptd joydev input_leds serio_raw i2c_piix4 vmw_vmci shpchp 8250_fintek mac_hid
> ib_iser rdma_cm iw_cm ib_cm ib_sa ib_mad ib_core ib_addr iscsi_tcp libiscsi_tcp libiscsi
> scsi_transport_iscsi parport_pc ppdev lp parport autofs4 hid_generic usbhid hid vmwgfx ttm psmouse
> drm_kms_helper syscopyarea
> [ 862.784609] sysfillrect sysimgblt mptspi mptscsih fb_sys_fops drm ahci libahci e1000 mptbase
> scsi_transport_spi pata_acpi floppy fjes
> [ 862.784618] CPU: 0 PID: 9241 Comm: iscsi_np Tainted: G OE 4.4.0-24-generic #43-Ubuntu
> [ 862.784620] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform,
> BIOS 6.00 05/20/2014
> [ 862.784622] task: ffff8800759d1b80 ti: ffff880075a00000 task.ti: ffff880075a00000
> [ 862.784624] RIP: 0010:[<ffffffffc0604b44>] [<ffffffffc0604b44>]
> iscsi_target_login_thread+0x724/0xfa0 [iscsi_target_mod]
> [ 862.784632] RSP: 0018:ffff880075a03e40 EFLAGS: 00010246
> [ 862.784633] RAX: 0000000000000000 RBX: ffff880075a52800 RCX: 0000000000037726
> [ 862.784635] RDX: 0000000000037725 RSI: ffff88007b619fe0 RDI: ffff880033bce800
> [ 862.784636] RBP: ffff880075a03ec0 R08: 0000000000019fe0 R09: ffffffffc06067c6
> [ 862.784637] R10: ffffea0001d1d880 R11: 654d687475410032 R12: ffff880074763140
> [ 862.784638] R13: ffff880075a52820 R14: ffff880075a528d8 R15: ffff880033bce800
> [ 862.784640] FS: 0000000000000000(0000) GS:ffff88007b600000(0000) knlGS:0000000000000000
> [ 862.784641] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
> [ 862.784642] CR2: 00000000000001f8 CR3: 0000000072f8e000 CR4: 00000000000406f0
> [ 862.784716] Stack:
> [ 862.784719] ffff880075e87080 ffff88003526f358 ffff8800799cc420 ffff880000000000
> [ 862.784721] ffff880079cd0100 ffff880075a52828 00ff88003526ee00 ffff880075a528d8
> [ 862.784723] ffff8800759d1b80 ffff880075a52800 0000000058f0fa77 ffff880075a0aac0
> [ 862.784725] Call Trace:
> [ 862.784736] [<ffffffffc0604420>] ? iscsi_target_login_sess_out+0x240/0x240 [iscsi_target_mod]
> [ 862.784782] [<ffffffff810a06a8>] kthread+0xd8/0xf0
> [ 862.784786] [<ffffffff810a05d0>] ? kthread_create_on_node+0x1e0/0x1e0
> [ 862.784789] [<ffffffff81825f8f>] ret_from_fork+0x3f/0x70
> [ 862.784791] [<ffffffff810a05d0>] ? kthread_create_on_node+0x1e0/0x1e0
> [ 862.784792] Code: 00 00 4c 89 e2 4c 89 fe 48 89 df e8 c7 19 00 00 85 c0 0f 88 32 01 00 00 0f b6 45 b7 4c 89 ff 41 88 44 24 09
> 49 8b 87 48 05 00 00 <4c> 8b b0 f8 01 00 00 49 8b 87 10 05 00 00 ff 90 98 00 00 00 41
> [ 862.784811] RIP [<ffffffffc0604b44>] iscsi_target_login_thread+0x724/0xfa0 [iscsi_target_mod]
> [ 862.784819] RSP <ffff880075a03e40>
> [ 862.784820] CR2: 00000000000001f8
> [ 862.784823] ---[ end trace 7e41630f165c8027 ]---
>
> Regards,
> Sumit Rai
>> On Jul 12, 2016, at 8:46 AM, Feng Li <lifeng1519@xxxxxxxxx> wrote:
>>
>> 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)
>



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