Re: [PATCH RESEND] iscsi: Don't destroy session if there are outstanding connections

2020-01-15 Thread Martin K. Petersen 


Gabriel,

> A faulty userspace that calls destroy_session() before destroying the
> connections can trigger the failure.  This patch prevents the issue by
> refusing to destroy the session if there are outstanding connections.

Applied to 5.6/scsi-queue, thanks!

-- 
Martin K. Petersen  Oracle Linux Engineering

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Re: [PATCH RESEND] iscsi: Don't destroy session if there are outstanding connections

2020-01-14 Thread Lee Duncan 
On 1/13/20 2:36 PM, Gabriel Krisman Bertazi wrote:
> Gabriel Krisman Bertazi  writes:
> 
>> From: Nick Black 
>>
>> Hi,
>>
>> I thought this was already committed for some reason, until it bit me
>> again today.  Any opposition to this one?
> 
> Hi,
> 
> Pinging this patch.  Any oposion?
> 
>>> 8
>>
>> A faulty userspace that calls destroy_session() before destroying the
>> connections can trigger the failure.  This patch prevents the
>> issue by refusing to destroy the session if there are outstanding
>> connections.
>>
>> [ cut here ]
>> kernel BUG at mm/slub.c:306!
>> invalid opcode:  [#1] SMP PTI
>> CPU: 1 PID: 1224 Comm: iscsid Not tainted 5.4.0-rc2.iscsi+ #7
>> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 
>> 04/01/2014
>> RIP: 0010:__slab_free+0x181/0x350
>> [...]
>> [ 1209.686056] RSP: 0018:a93d4074fae0 EFLAGS: 00010246
>> [ 1209.686694] RAX: 934efa5ad800 RBX: 801a RCX: 
>> 934efa5ad800
>> [ 1209.687651] RDX: 934efa5ad800 RSI: eb4041e96b00 RDI: 
>> 934efd402c40
>> [ 1209.688582] RBP: a93d4074fb80 R08: 0001 R09: 
>> bb5dfa26
>> [ 1209.689425] R10: 934efa5ad800 R11: 0001 R12: 
>> eb4041e96b00
>> [ 1209.690285] R13: 934efa5ad800 R14: 934efd402c40 R15: 
>> 
>> [ 1209.691213] FS:  7f7945dfb540() GS:934efda8() 
>> knlGS:
>> [ 1209.692316] CS:  0010 DS:  ES:  CR0: 80050033
>> [ 1209.693013] CR2: 55877fd3da80 CR3: 77384000 CR4: 
>> 06e0
>> [ 1209.693897] DR0:  DR1:  DR2: 
>> 
>> [ 1209.694773] DR3:  DR6: fffe0ff0 DR7: 
>> 0400
>> [ 1209.695631] Call Trace:
>> [ 1209.695957]  ? __wake_up_common_lock+0x8a/0xc0
>> [ 1209.696712]  iscsi_pool_free+0x26/0x40
>> [ 1209.697263]  iscsi_session_teardown+0x2f/0xf0
>> [ 1209.698117]  iscsi_sw_tcp_session_destroy+0x45/0x60
>> [ 1209.698831]  iscsi_if_rx+0xd88/0x14e0
>> [ 1209.699370]  netlink_unicast+0x16f/0x200
>> [ 1209.699932]  netlink_sendmsg+0x21a/0x3e0
>> [ 1209.700446]  sock_sendmsg+0x4f/0x60
>> [ 1209.700902]  ___sys_sendmsg+0x2ae/0x320
>> [ 1209.701451]  ? cp_new_stat+0x150/0x180
>> [ 1209.701922]  __sys_sendmsg+0x59/0xa0
>> [ 1209.702357]  do_syscall_64+0x52/0x160
>> [ 1209.702812]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
>> [ 1209.703419] RIP: 0033:0x7f7946433914
>> [...]
>> [ 1209.706084] RSP: 002b:7fffb99f2378 EFLAGS: 0246 ORIG_RAX: 
>> 002e
>> [ 1209.706994] RAX: ffda RBX: 55bc869eac20 RCX: 
>> 7f7946433914
>> [ 1209.708082] RDX:  RSI: 7fffb99f2390 RDI: 
>> 0005
>> [ 1209.709120] RBP: 7fffb99f2390 R08: 55bc84fe9320 R09: 
>> 7fffb99f1f07
>> [ 1209.710110] R10:  R11: 0246 R12: 
>> 0038
>> [ 1209.711085] R13: 55bc8502306e R14:  R15: 
>> 
>>  Modules linked in:
>>  ---[ end trace a2d933ede7f730d8 ]---
>>
>> Co-developed-by: Salman Qazi 
>> Signed-off-by: Salman Qazi 
>> Co-developed-by: Junho Ryu 
>> Signed-off-by: Junho Ryu 
>> Co-developed-by: Khazhismel Kumykov 
>> Signed-off-by: Khazhismel Kumykov 
>> Signed-off-by: Nick Black 
>> Co-developed-by: Gabriel Krisman Bertazi 
>> Signed-off-by: Gabriel Krisman Bertazi 
>> ---
>>  drivers/scsi/iscsi_tcp.c|  4 
>>  drivers/scsi/scsi_transport_iscsi.c | 26 +++---
>>  2 files changed, 27 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c
>> index 0bc63a7ab41c..b5dd1caae5e9 100644
>> --- a/drivers/scsi/iscsi_tcp.c
>> +++ b/drivers/scsi/iscsi_tcp.c
>> @@ -887,6 +887,10 @@ iscsi_sw_tcp_session_create(struct iscsi_endpoint *ep, 
>> uint16_t cmds_max,
>>  static void iscsi_sw_tcp_session_destroy(struct iscsi_cls_session 
>> *cls_session)
>>  {
>>  struct Scsi_Host *shost = iscsi_session_to_shost(cls_session);
>> +struct iscsi_session *session = cls_session->dd_data;
>> +
>> +if (WARN_ON_ONCE(session->leadconn))
>> +return;
>>  
>>  iscsi_tcp_r2tpool_free(cls_session->dd_data);
>>  iscsi_session_teardown(cls_session);
>> diff --git a/drivers/scsi/scsi_transport_iscsi.c 
>> b/drivers/scsi/scsi_transport_iscsi.c
>> index ed8d9709b9b9..271afea654e2 100644
>> --- a/drivers/scsi/scsi_transport_iscsi.c
>> +++ b/drivers/scsi/scsi_transport_iscsi.c
>> @@ -2947,6 +2947,24 @@ iscsi_set_path(struct iscsi_transport *transport, 
>> struct iscsi_uevent *ev)
>>  return err;
>>  }
>>  
>> +static int iscsi_session_has_conns(int sid)
>> +{
>> +struct iscsi_cls_conn *conn;
>> +unsigned long flags;
>> +int found = 0;
>> +
>> +spin_lock_irqsave(, flags);
>> +list_for_each_entry(conn, , conn_list) {
>> +if (iscsi_conn_get_sid(conn) == sid) {
>> +found = 1;
>> +break;
>> +

Re: [PATCH RESEND] iscsi: Don't destroy session if there are outstanding connections

2020-01-13 Thread Gabriel Krisman Bertazi 
Gabriel Krisman Bertazi  writes:

> From: Nick Black 
>
> Hi,
>
> I thought this was already committed for some reason, until it bit me
> again today.  Any opposition to this one?

Hi,

Pinging this patch.  Any oposion?

>>8
>
> A faulty userspace that calls destroy_session() before destroying the
> connections can trigger the failure.  This patch prevents the
> issue by refusing to destroy the session if there are outstanding
> connections.
>
> [ cut here ]
> kernel BUG at mm/slub.c:306!
> invalid opcode:  [#1] SMP PTI
> CPU: 1 PID: 1224 Comm: iscsid Not tainted 5.4.0-rc2.iscsi+ #7
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 
> 04/01/2014
> RIP: 0010:__slab_free+0x181/0x350
> [...]
> [ 1209.686056] RSP: 0018:a93d4074fae0 EFLAGS: 00010246
> [ 1209.686694] RAX: 934efa5ad800 RBX: 801a RCX: 
> 934efa5ad800
> [ 1209.687651] RDX: 934efa5ad800 RSI: eb4041e96b00 RDI: 
> 934efd402c40
> [ 1209.688582] RBP: a93d4074fb80 R08: 0001 R09: 
> bb5dfa26
> [ 1209.689425] R10: 934efa5ad800 R11: 0001 R12: 
> eb4041e96b00
> [ 1209.690285] R13: 934efa5ad800 R14: 934efd402c40 R15: 
> 
> [ 1209.691213] FS:  7f7945dfb540() GS:934efda8() 
> knlGS:
> [ 1209.692316] CS:  0010 DS:  ES:  CR0: 80050033
> [ 1209.693013] CR2: 55877fd3da80 CR3: 77384000 CR4: 
> 06e0
> [ 1209.693897] DR0:  DR1:  DR2: 
> 
> [ 1209.694773] DR3:  DR6: fffe0ff0 DR7: 
> 0400
> [ 1209.695631] Call Trace:
> [ 1209.695957]  ? __wake_up_common_lock+0x8a/0xc0
> [ 1209.696712]  iscsi_pool_free+0x26/0x40
> [ 1209.697263]  iscsi_session_teardown+0x2f/0xf0
> [ 1209.698117]  iscsi_sw_tcp_session_destroy+0x45/0x60
> [ 1209.698831]  iscsi_if_rx+0xd88/0x14e0
> [ 1209.699370]  netlink_unicast+0x16f/0x200
> [ 1209.699932]  netlink_sendmsg+0x21a/0x3e0
> [ 1209.700446]  sock_sendmsg+0x4f/0x60
> [ 1209.700902]  ___sys_sendmsg+0x2ae/0x320
> [ 1209.701451]  ? cp_new_stat+0x150/0x180
> [ 1209.701922]  __sys_sendmsg+0x59/0xa0
> [ 1209.702357]  do_syscall_64+0x52/0x160
> [ 1209.702812]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
> [ 1209.703419] RIP: 0033:0x7f7946433914
> [...]
> [ 1209.706084] RSP: 002b:7fffb99f2378 EFLAGS: 0246 ORIG_RAX: 
> 002e
> [ 1209.706994] RAX: ffda RBX: 55bc869eac20 RCX: 
> 7f7946433914
> [ 1209.708082] RDX:  RSI: 7fffb99f2390 RDI: 
> 0005
> [ 1209.709120] RBP: 7fffb99f2390 R08: 55bc84fe9320 R09: 
> 7fffb99f1f07
> [ 1209.710110] R10:  R11: 0246 R12: 
> 0038
> [ 1209.711085] R13: 55bc8502306e R14:  R15: 
> 
>  Modules linked in:
>  ---[ end trace a2d933ede7f730d8 ]---
>
> Co-developed-by: Salman Qazi 
> Signed-off-by: Salman Qazi 
> Co-developed-by: Junho Ryu 
> Signed-off-by: Junho Ryu 
> Co-developed-by: Khazhismel Kumykov 
> Signed-off-by: Khazhismel Kumykov 
> Signed-off-by: Nick Black 
> Co-developed-by: Gabriel Krisman Bertazi 
> Signed-off-by: Gabriel Krisman Bertazi 
> ---
>  drivers/scsi/iscsi_tcp.c|  4 
>  drivers/scsi/scsi_transport_iscsi.c | 26 +++---
>  2 files changed, 27 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c
> index 0bc63a7ab41c..b5dd1caae5e9 100644
> --- a/drivers/scsi/iscsi_tcp.c
> +++ b/drivers/scsi/iscsi_tcp.c
> @@ -887,6 +887,10 @@ iscsi_sw_tcp_session_create(struct iscsi_endpoint *ep, 
> uint16_t cmds_max,
>  static void iscsi_sw_tcp_session_destroy(struct iscsi_cls_session 
> *cls_session)
>  {
>   struct Scsi_Host *shost = iscsi_session_to_shost(cls_session);
> + struct iscsi_session *session = cls_session->dd_data;
> +
> + if (WARN_ON_ONCE(session->leadconn))
> + return;
>  
>   iscsi_tcp_r2tpool_free(cls_session->dd_data);
>   iscsi_session_teardown(cls_session);
> diff --git a/drivers/scsi/scsi_transport_iscsi.c 
> b/drivers/scsi/scsi_transport_iscsi.c
> index ed8d9709b9b9..271afea654e2 100644
> --- a/drivers/scsi/scsi_transport_iscsi.c
> +++ b/drivers/scsi/scsi_transport_iscsi.c
> @@ -2947,6 +2947,24 @@ iscsi_set_path(struct iscsi_transport *transport, 
> struct iscsi_uevent *ev)
>   return err;
>  }
>  
> +static int iscsi_session_has_conns(int sid)
> +{
> + struct iscsi_cls_conn *conn;
> + unsigned long flags;
> + int found = 0;
> +
> + spin_lock_irqsave(, flags);
> + list_for_each_entry(conn, , conn_list) {
> + if (iscsi_conn_get_sid(conn) == sid) {
> + found = 1;
> + break;
> + }
> + }
> + spin_unlock_irqrestore(, flags);
> +
> + return found;
> +}
> +
>  static int
>  iscsi_set_iface_params(struct iscsi_transport *transport,
>

Re: [PATCH RESEND] iscsi: Don't destroy session if there are outstanding connections

2020-01-10 Thread The Lee-Man 


On Thursday, December 26, 2019 at 12:31:55 PM UTC-8, Gabriel Krisman 
Bertazi wrote:
>
> From: Nick Black  
>
> Hi, 
>
> I thought this was already committed for some reason, until it bit me 
> again today.  Any opposition to this one? 
>
> >8 
>
> A faulty userspace that calls destroy_session() before destroying the 
> connections can trigger the failure.  This patch prevents the 
> issue by refusing to destroy the session if there are outstanding 
> connections. 
>
> [ cut here ] 
> kernel BUG at mm/slub.c:306! 
> invalid opcode:  [#1] SMP PTI 
> CPU: 1 PID: 1224 Comm: iscsid Not tainted 5.4.0-rc2.iscsi+ #7 
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 
> 04/01/2014 
> RIP: 0010:__slab_free+0x181/0x350 
> [...] 
> [ 1209.686056] RSP: 0018:a93d4074fae0 EFLAGS: 00010246 
> [ 1209.686694] RAX: 934efa5ad800 RBX: 801a RCX: 
> 934efa5ad800 
> [ 1209.687651] RDX: 934efa5ad800 RSI: eb4041e96b00 RDI: 
> 934efd402c40 
> [ 1209.688582] RBP: a93d4074fb80 R08: 0001 R09: 
> bb5dfa26 
> [ 1209.689425] R10: 934efa5ad800 R11: 0001 R12: 
> eb4041e96b00 
> [ 1209.690285] R13: 934efa5ad800 R14: 934efd402c40 R15: 
>  
> [ 1209.691213] FS:  7f7945dfb540() GS:934efda8() 
> knlGS: 
> [ 1209.692316] CS:  0010 DS:  ES:  CR0: 80050033 
> [ 1209.693013] CR2: 55877fd3da80 CR3: 77384000 CR4: 
> 06e0 
> [ 1209.693897] DR0:  DR1:  DR2: 
>  
> [ 1209.694773] DR3:  DR6: fffe0ff0 DR7: 
> 0400 
> [ 1209.695631] Call Trace: 
> [ 1209.695957]  ? __wake_up_common_lock+0x8a/0xc0 
> [ 1209.696712]  iscsi_pool_free+0x26/0x40 
> [ 1209.697263]  iscsi_session_teardown+0x2f/0xf0 
> [ 1209.698117]  iscsi_sw_tcp_session_destroy+0x45/0x60 
> [ 1209.698831]  iscsi_if_rx+0xd88/0x14e0 
> [ 1209.699370]  netlink_unicast+0x16f/0x200 
> [ 1209.699932]  netlink_sendmsg+0x21a/0x3e0 
> [ 1209.700446]  sock_sendmsg+0x4f/0x60 
> [ 1209.700902]  ___sys_sendmsg+0x2ae/0x320 
> [ 1209.701451]  ? cp_new_stat+0x150/0x180 
> [ 1209.701922]  __sys_sendmsg+0x59/0xa0 
> [ 1209.702357]  do_syscall_64+0x52/0x160 
> [ 1209.702812]  entry_SYSCALL_64_after_hwframe+0x44/0xa9 
> [ 1209.703419] RIP: 0033:0x7f7946433914 
> [...] 
> [ 1209.706084] RSP: 002b:7fffb99f2378 EFLAGS: 0246 ORIG_RAX: 
> 002e 
> [ 1209.706994] RAX: ffda RBX: 55bc869eac20 RCX: 
> 7f7946433914 
> [ 1209.708082] RDX:  RSI: 7fffb99f2390 RDI: 
> 0005 
> [ 1209.709120] RBP: 7fffb99f2390 R08: 55bc84fe9320 R09: 
> 7fffb99f1f07 
> [ 1209.710110] R10:  R11: 0246 R12: 
> 0038 
> [ 1209.711085] R13: 55bc8502306e R14:  R15: 
>  
>  Modules linked in: 
>  ---[ end trace a2d933ede7f730d8 ]--- 
>
> Co-developed-by: Salman Qazi  
> Signed-off-by: Salman Qazi  
> Co-developed-by: Junho Ryu  
> Signed-off-by: Junho Ryu  
> Co-developed-by: Khazhismel Kumykov  
> Signed-off-by: Khazhismel Kumykov  
> Signed-off-by: Nick Black  
> Co-developed-by: Gabriel Krisman Bertazi  
> Signed-off-by: Gabriel Krisman Bertazi  
> --- 
>  drivers/scsi/iscsi_tcp.c|  4  
>  drivers/scsi/scsi_transport_iscsi.c | 26 +++--- 
>  2 files changed, 27 insertions(+), 3 deletions(-) 
>
> diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c 
> index 0bc63a7ab41c..b5dd1caae5e9 100644 
> --- a/drivers/scsi/iscsi_tcp.c 
> +++ b/drivers/scsi/iscsi_tcp.c 
> @@ -887,6 +887,10 @@ iscsi_sw_tcp_session_create(struct iscsi_endpoint 
> *ep, uint16_t cmds_max, 
>  static void iscsi_sw_tcp_session_destroy(struct iscsi_cls_session 
> *cls_session) 
>  { 
>  struct Scsi_Host *shost = iscsi_session_to_shost(cls_session); 
> +struct iscsi_session *session = cls_session->dd_data; 
> + 
> +if (WARN_ON_ONCE(session->leadconn)) 
> +return; 
>   
>  iscsi_tcp_r2tpool_free(cls_session->dd_data); 
>  iscsi_session_teardown(cls_session); 
> diff --git a/drivers/scsi/scsi_transport_iscsi.c 
> b/drivers/scsi/scsi_transport_iscsi.c 
> index ed8d9709b9b9..271afea654e2 100644 
> --- a/drivers/scsi/scsi_transport_iscsi.c 
> +++ b/drivers/scsi/scsi_transport_iscsi.c 
> @@ -2947,6 +2947,24 @@ iscsi_set_path(struct iscsi_transport *transport, 
> struct iscsi_uevent *ev) 
>  return err; 
>  } 
>   
> +static int iscsi_session_has_conns(int sid) 
> +{ 
> +struct iscsi_cls_conn *conn; 
> +unsigned long flags; 
> +int found = 0; 
> + 
> +spin_lock_irqsave(, flags); 
> +list_for_each_entry(conn, , conn_list) { 
> +if (iscsi_conn_get_sid(conn) == sid) { 
> +found = 1; 
> +break; 
> +} 
> +

[PATCH RESEND] iscsi: Don't destroy session if there are outstanding connections

2019-12-26 Thread Gabriel Krisman Bertazi 
From: Nick Black 

Hi,

I thought this was already committed for some reason, until it bit me
again today.  Any opposition to this one?

>8

A faulty userspace that calls destroy_session() before destroying the
connections can trigger the failure.  This patch prevents the
issue by refusing to destroy the session if there are outstanding
connections.

[ cut here ]
kernel BUG at mm/slub.c:306!
invalid opcode:  [#1] SMP PTI
CPU: 1 PID: 1224 Comm: iscsid Not tainted 5.4.0-rc2.iscsi+ #7
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
RIP: 0010:__slab_free+0x181/0x350
[...]
[ 1209.686056] RSP: 0018:a93d4074fae0 EFLAGS: 00010246
[ 1209.686694] RAX: 934efa5ad800 RBX: 801a RCX: 934efa5ad800
[ 1209.687651] RDX: 934efa5ad800 RSI: eb4041e96b00 RDI: 934efd402c40
[ 1209.688582] RBP: a93d4074fb80 R08: 0001 R09: bb5dfa26
[ 1209.689425] R10: 934efa5ad800 R11: 0001 R12: eb4041e96b00
[ 1209.690285] R13: 934efa5ad800 R14: 934efd402c40 R15: 
[ 1209.691213] FS:  7f7945dfb540() GS:934efda8() 
knlGS:
[ 1209.692316] CS:  0010 DS:  ES:  CR0: 80050033
[ 1209.693013] CR2: 55877fd3da80 CR3: 77384000 CR4: 06e0
[ 1209.693897] DR0:  DR1:  DR2: 
[ 1209.694773] DR3:  DR6: fffe0ff0 DR7: 0400
[ 1209.695631] Call Trace:
[ 1209.695957]  ? __wake_up_common_lock+0x8a/0xc0
[ 1209.696712]  iscsi_pool_free+0x26/0x40
[ 1209.697263]  iscsi_session_teardown+0x2f/0xf0
[ 1209.698117]  iscsi_sw_tcp_session_destroy+0x45/0x60
[ 1209.698831]  iscsi_if_rx+0xd88/0x14e0
[ 1209.699370]  netlink_unicast+0x16f/0x200
[ 1209.699932]  netlink_sendmsg+0x21a/0x3e0
[ 1209.700446]  sock_sendmsg+0x4f/0x60
[ 1209.700902]  ___sys_sendmsg+0x2ae/0x320
[ 1209.701451]  ? cp_new_stat+0x150/0x180
[ 1209.701922]  __sys_sendmsg+0x59/0xa0
[ 1209.702357]  do_syscall_64+0x52/0x160
[ 1209.702812]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 1209.703419] RIP: 0033:0x7f7946433914
[...]
[ 1209.706084] RSP: 002b:7fffb99f2378 EFLAGS: 0246 ORIG_RAX: 
002e
[ 1209.706994] RAX: ffda RBX: 55bc869eac20 RCX: 7f7946433914
[ 1209.708082] RDX:  RSI: 7fffb99f2390 RDI: 0005
[ 1209.709120] RBP: 7fffb99f2390 R08: 55bc84fe9320 R09: 7fffb99f1f07
[ 1209.710110] R10:  R11: 0246 R12: 0038
[ 1209.711085] R13: 55bc8502306e R14:  R15: 
 Modules linked in:
 ---[ end trace a2d933ede7f730d8 ]---

Co-developed-by: Salman Qazi 
Signed-off-by: Salman Qazi 
Co-developed-by: Junho Ryu 
Signed-off-by: Junho Ryu 
Co-developed-by: Khazhismel Kumykov 
Signed-off-by: Khazhismel Kumykov 
Signed-off-by: Nick Black 
Co-developed-by: Gabriel Krisman Bertazi 
Signed-off-by: Gabriel Krisman Bertazi 
---
 drivers/scsi/iscsi_tcp.c|  4 
 drivers/scsi/scsi_transport_iscsi.c | 26 +++---
 2 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c
index 0bc63a7ab41c..b5dd1caae5e9 100644
--- a/drivers/scsi/iscsi_tcp.c
+++ b/drivers/scsi/iscsi_tcp.c
@@ -887,6 +887,10 @@ iscsi_sw_tcp_session_create(struct iscsi_endpoint *ep, 
uint16_t cmds_max,
 static void iscsi_sw_tcp_session_destroy(struct iscsi_cls_session *cls_session)
 {
struct Scsi_Host *shost = iscsi_session_to_shost(cls_session);
+   struct iscsi_session *session = cls_session->dd_data;
+
+   if (WARN_ON_ONCE(session->leadconn))
+   return;
 
iscsi_tcp_r2tpool_free(cls_session->dd_data);
iscsi_session_teardown(cls_session);
diff --git a/drivers/scsi/scsi_transport_iscsi.c 
b/drivers/scsi/scsi_transport_iscsi.c
index ed8d9709b9b9..271afea654e2 100644
--- a/drivers/scsi/scsi_transport_iscsi.c
+++ b/drivers/scsi/scsi_transport_iscsi.c
@@ -2947,6 +2947,24 @@ iscsi_set_path(struct iscsi_transport *transport, struct 
iscsi_uevent *ev)
return err;
 }
 
+static int iscsi_session_has_conns(int sid)
+{
+   struct iscsi_cls_conn *conn;
+   unsigned long flags;
+   int found = 0;
+
+   spin_lock_irqsave(, flags);
+   list_for_each_entry(conn, , conn_list) {
+   if (iscsi_conn_get_sid(conn) == sid) {
+   found = 1;
+   break;
+   }
+   }
+   spin_unlock_irqrestore(, flags);
+
+   return found;
+}
+
 static int
 iscsi_set_iface_params(struct iscsi_transport *transport,
   struct iscsi_uevent *ev, uint32_t len)
@@ -3524,10 +3542,12 @@ iscsi_if_recv_msg(struct sk_buff *skb, struct nlmsghdr 
*nlh, uint32_t *group)
break;
case ISCSI_UEVENT_DESTROY_SESSION:
session = iscsi_session_lookup(ev->u.d_session.sid);
-   if