sctp: Fix oops when sending queued ASCONF chunks

When we finish processing ASCONF_ACK chunk, we try to send
the next queued ASCONF.  This action runs the sctp state
machine recursively and it's not prepared to do so.

kernel BUG at kernel/timer.c:790!
invalid opcode: 0000 [#1] SMP
last sysfs file: /sys/module/ipv6/initstate
Modules linked in: sha256_generic sctp libcrc32c ipv6 dm_multipath
uinput 8139too i2c_piix4 8139cp mii i2c_core pcspkr virtio_net joydev
floppy virtio_blk virtio_pci [last unloaded: scsi_wait_scan]

Pid: 0, comm: swapper Not tainted 2.6.34-rc4 #15 /Bochs
EIP: 0060:[<c044a2ef>] EFLAGS: 00010286 CPU: 0
EIP is at add_timer+0xd/0x1b
EAX: cecbab14 EBX: 000000f0 ECX: c0957b1c EDX: 03595cf4
ESI: cecba800 EDI: cf276f00 EBP: c0957aa0 ESP: c0957aa0
 DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
Process swapper (pid: 0, ti=c0956000 task=c0988ba0 task.ti=c0956000)
Stack:
 c0957ae0 d1851214 c0ab62e4 c0ab5f26 0500ffff 00000004 00000005 00000004
<0> 00000000 d18694fd 00000004 1666b892 cecba800 cecba800 c0957b14
00000004
<0> c0957b94 d1851b11 ceda8b00 cecba800 cf276f00 00000001 c0957b14
000000d0
Call Trace:
 [<d1851214>] ? sctp_side_effects+0x607/0xdfc [sctp]
 [<d1851b11>] ? sctp_do_sm+0x108/0x159 [sctp]
 [<d1863386>] ? sctp_pname+0x0/0x1d [sctp]
 [<d1861a56>] ? sctp_primitive_ASCONF+0x36/0x3b [sctp]
 [<d185657c>] ? sctp_process_asconf_ack+0x2a4/0x2d3 [sctp]
 [<d184e35c>] ? sctp_sf_do_asconf_ack+0x1dd/0x2b4 [sctp]
 [<d1851ac1>] ? sctp_do_sm+0xb8/0x159 [sctp]
 [<d1863334>] ? sctp_cname+0x0/0x52 [sctp]
 [<d1854377>] ? sctp_assoc_bh_rcv+0xac/0xe1 [sctp]
 [<d1858f0f>] ? sctp_inq_push+0x2d/0x30 [sctp]
 [<d186329d>] ? sctp_rcv+0x797/0x82e [sctp]

Tested-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: Yuansong Qiao <ysqiao@research.ait.ie>
Signed-off-by: Shuaijun Zhang <szhang@research.ait.ie>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 33 insertions, 16 deletions

diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
index f6fc5c1a4078..0fd5b4c88358 100644
--- a/net/sctp/sm_make_chunk.c
+++ b/net/sctp/sm_make_chunk.c
@@ -3318,21 +3318,6 @@ int sctp_process_asconf_ack(struct sctp_association *asoc,
         sctp_chunk_free(asconf);
         asoc->addip_last_asconf = NULL;
 
-        /* Send the next asconf chunk from the addip chunk queue. */
-        if (!list_empty(&asoc->addip_chunk_list)) {
-                struct list_head *entry = asoc->addip_chunk_list.next;
-                asconf = list_entry(entry, struct sctp_chunk, list);
-
-                list_del_init(entry);
-
-                /* Hold the chunk until an ASCONF_ACK is received. */
-                sctp_chunk_hold(asconf);
-                if (sctp_primitive_ASCONF(asoc, asconf))
-                        sctp_chunk_free(asconf);
-                else
-                        asoc->addip_last_asconf = asconf;
-        }
-
         return retval;
 }
 
diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
index 4c5bed9af4e3..d5ae450b6f02 100644
--- a/net/sctp/sm_sideeffect.c
+++ b/net/sctp/sm_sideeffect.c
@@ -962,6 +962,29 @@ static int sctp_cmd_send_msg(struct sctp_association *asoc,
 }
 
 
+/* Sent the next ASCONF packet currently stored in the association.
+ * This happens after the ASCONF_ACK was succeffully processed.
+ */
+static void sctp_cmd_send_asconf(struct sctp_association *asoc)
+{
+        /* Send the next asconf chunk from the addip chunk
+         * queue.
+         */
+        if (!list_empty(&asoc->addip_chunk_list)) {
+                struct list_head *entry = asoc->addip_chunk_list.next;
+                struct sctp_chunk *asconf = list_entry(entry,
+                                                struct sctp_chunk, list);
+                list_del_init(entry);
+
+                /* Hold the chunk until an ASCONF_ACK is received. */
+                sctp_chunk_hold(asconf);
+                if (sctp_primitive_ASCONF(asoc, asconf))
+                        sctp_chunk_free(asconf);
+                else
+                        asoc->addip_last_asconf = asconf;
+        }
+}
+
 
 /* These three macros allow us to pull the debugging code out of the
  * main flow of sctp_do_sm() to keep attention focused on the real
@@ -1617,6 +1640,9 @@ static int sctp_cmd_interpreter(sctp_event_t event_type,
                         }
                         error = sctp_cmd_send_msg(asoc, cmd->obj.msg);
                         break;
+                case SCTP_CMD_SEND_NEXT_ASCONF:
+                        sctp_cmd_send_asconf(asoc);
+                        break;
                 default:
                         printk(KERN_WARNING "Impossible command: %u, %p\n",
                                cmd->verb, cmd->obj.ptr);
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index abf601a1b847..24b2cd555637 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -3676,8 +3676,14 @@ sctp_disposition_t sctp_sf_do_asconf_ack(const struct sctp_endpoint *ep,
                                 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
 
                 if (!sctp_process_asconf_ack((struct sctp_association *)asoc,
-                                             asconf_ack))
+                                             asconf_ack)) {
+                        /* Successfully processed ASCONF_ACK.  We can
+                         * release the next asconf if we have one.
+                         */
+                        sctp_add_cmd_sf(commands, SCTP_CMD_SEND_NEXT_ASCONF,
+                                        SCTP_NULL());
                         return SCTP_DISPOSITION_CONSUME;
+                }
 
                 abort = sctp_make_abort(asoc, asconf_ack,
                                         sizeof(sctp_errhdr_t));