On Thursday, December 26, 2019 at 12:31:55 PM UTC-8, Gabriel Krisman
Bertazi wrote:
>
> From: Nick Black <n...@google.com>
>
> 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: 0000 [#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:ffffa93d4074fae0 EFLAGS: 00010246
> [ 1209.686694] RAX: ffff934efa5ad800 RBX: 000000008010000a RCX:
> ffff934efa5ad800
> [ 1209.687651] RDX: ffff934efa5ad800 RSI: ffffeb4041e96b00 RDI:
> ffff934efd402c40
> [ 1209.688582] RBP: ffffa93d4074fb80 R08: 0000000000000001 R09:
> ffffffffbb5dfa26
> [ 1209.689425] R10: ffff934efa5ad800 R11: 0000000000000001 R12:
> ffffeb4041e96b00
> [ 1209.690285] R13: ffff934efa5ad800 R14: ffff934efd402c40 R15:
> 0000000000000000
> [ 1209.691213] FS: 00007f7945dfb540(0000) GS:ffff934efda80000(0000)
> knlGS:0000000000000000
> [ 1209.692316] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 1209.693013] CR2: 000055877fd3da80 CR3: 0000000077384000 CR4:
> 00000000000006e0
> [ 1209.693897] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
> 0000000000000000
> [ 1209.694773] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7:
> 0000000000000400
> [ 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:00007fffb99f2378 EFLAGS: 00000246 ORIG_RAX:
> 000000000000002e
> [ 1209.706994] RAX: ffffffffffffffda RBX: 000055bc869eac20 RCX:
> 00007f7946433914
> [ 1209.708082] RDX: 0000000000000000 RSI: 00007fffb99f2390 RDI:
> 0000000000000005
> [ 1209.709120] RBP: 00007fffb99f2390 R08: 000055bc84fe9320 R09:
> 00007fffb99f1f07
> [ 1209.710110] R10: 0000000000000000 R11: 0000000000000246 R12:
> 0000000000000038
> [ 1209.711085] R13: 000055bc8502306e R14: 0000000000000000 R15:
> 0000000000000000
> Modules linked in:
> ---[ end trace a2d933ede7f730d8 ]---
>
> Co-developed-by: Salman Qazi <sq...@google.com>
> Signed-off-by: Salman Qazi <sq...@google.com>
> Co-developed-by: Junho Ryu <j...@google.com>
> Signed-off-by: Junho Ryu <j...@google.com>
> Co-developed-by: Khazhismel Kumykov <kha...@google.com>
> Signed-off-by: Khazhismel Kumykov <kha...@google.com>
> Signed-off-by: Nick Black <n...@google.com>
> Co-developed-by: Gabriel Krisman Bertazi <kris...@collabora.com>
> Signed-off-by: Gabriel Krisman Bertazi <kris...@collabora.com>
> ---
> 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(&connlock, flags);
> + list_for_each_entry(conn, &connlist, conn_list) {
> + if (iscsi_conn_get_sid(conn) == sid) {
> + found = 1;
> + break;
> + }
> + }
> + spin_unlock_irqrestore(&connlock, 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 (session)
> - transport->destroy_session(session);
> - else
> + if (!session)
> err = -EINVAL;
> + else if (iscsi_session_has_conns(ev->u.d_session.sid))
> + err = -EBUSY;
> + else
> + transport->destroy_session(session);
> break;
> case ISCSI_UEVENT_UNBIND_SESSION:
> session = iscsi_session_lookup(ev->u.d_session.sid);
> --
> 2.24.1
>
>
Reviewed-by: Lee Duncan <ldun...@suse.com>
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