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authorXin Long <lucien.xin@gmail.com>2019-04-29 14:16:19 +0800
committerDavid S. Miller <davem@davemloft.net>2019-05-01 09:18:57 -0400
commitfbd019737d71e405f86549fd738f81e2ff3dd073 (patch)
tree9043120e7c2c2da0e4cb851f5d2bb9881ca3d6bb
parent37e9c087c81447cebd4ca022226829e319b0e280 (diff)
downloadlinux-fbd019737d71e405f86549fd738f81e2ff3dd073.tar.bz2
sctp: avoid running the sctp state machine recursively
Ying triggered a call trace when doing an asconf testing: BUG: scheduling while atomic: swapper/12/0/0x10000100 Call Trace: <IRQ> [<ffffffffa4375904>] dump_stack+0x19/0x1b [<ffffffffa436fcaf>] __schedule_bug+0x64/0x72 [<ffffffffa437b93a>] __schedule+0x9ba/0xa00 [<ffffffffa3cd5326>] __cond_resched+0x26/0x30 [<ffffffffa437bc4a>] _cond_resched+0x3a/0x50 [<ffffffffa3e22be8>] kmem_cache_alloc_node+0x38/0x200 [<ffffffffa423512d>] __alloc_skb+0x5d/0x2d0 [<ffffffffc0995320>] sctp_packet_transmit+0x610/0xa20 [sctp] [<ffffffffc098510e>] sctp_outq_flush+0x2ce/0xc00 [sctp] [<ffffffffc098646c>] sctp_outq_uncork+0x1c/0x20 [sctp] [<ffffffffc0977338>] sctp_cmd_interpreter.isra.22+0xc8/0x1460 [sctp] [<ffffffffc0976ad1>] sctp_do_sm+0xe1/0x350 [sctp] [<ffffffffc099443d>] sctp_primitive_ASCONF+0x3d/0x50 [sctp] [<ffffffffc0977384>] sctp_cmd_interpreter.isra.22+0x114/0x1460 [sctp] [<ffffffffc0976ad1>] sctp_do_sm+0xe1/0x350 [sctp] [<ffffffffc097b3a4>] sctp_assoc_bh_rcv+0xf4/0x1b0 [sctp] [<ffffffffc09840f1>] sctp_inq_push+0x51/0x70 [sctp] [<ffffffffc099732b>] sctp_rcv+0xa8b/0xbd0 [sctp] As it shows, the first sctp_do_sm() running under atomic context (NET_RX softirq) invoked sctp_primitive_ASCONF() that uses GFP_KERNEL flag later, and this flag is supposed to be used in non-atomic context only. Besides, sctp_do_sm() was called recursively, which is not expected. Vlad tried to fix this recursive call in Commit c0786693404c ("sctp: Fix oops when sending queued ASCONF chunks") by introducing a new command SCTP_CMD_SEND_NEXT_ASCONF. But it didn't work as this command is still used in the first sctp_do_sm() call, and sctp_primitive_ASCONF() will be called in this command again. To avoid calling sctp_do_sm() recursively, we send the next queued ASCONF not by sctp_primitive_ASCONF(), but by sctp_sf_do_prm_asconf() in the 1st sctp_do_sm() directly. Reported-by: Ying Xu <yinxu@redhat.com> Signed-off-by: Xin Long <lucien.xin@gmail.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/net/sctp/command.h1
-rw-r--r--net/sctp/sm_sideeffect.c29
-rw-r--r--net/sctp/sm_statefuns.c35
3 files changed, 27 insertions, 38 deletions
diff --git a/include/net/sctp/command.h b/include/net/sctp/command.h
index 6640f84fe536..6d5beac29bc1 100644
--- a/include/net/sctp/command.h
+++ b/include/net/sctp/command.h
@@ -105,7 +105,6 @@ enum sctp_verb {
SCTP_CMD_T1_RETRAN, /* Mark for retransmission after T1 timeout */
SCTP_CMD_UPDATE_INITTAG, /* Update peer inittag */
SCTP_CMD_SEND_MSG, /* Send the whole use message */
- SCTP_CMD_SEND_NEXT_ASCONF, /* Send the next ASCONF after ACK */
SCTP_CMD_PURGE_ASCONF_QUEUE, /* Purge all asconf queues.*/
SCTP_CMD_SET_ASOC, /* Restore association context */
SCTP_CMD_LAST
diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
index 1d143bc3f73d..4aa03588f87b 100644
--- a/net/sctp/sm_sideeffect.c
+++ b/net/sctp/sm_sideeffect.c
@@ -1112,32 +1112,6 @@ static void 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)
-{
- struct net *net = sock_net(asoc->base.sk);
-
- /* 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(net, 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
* functionality there.
@@ -1783,9 +1757,6 @@ static int sctp_cmd_interpreter(enum sctp_event_type event_type,
}
sctp_cmd_send_msg(asoc, cmd->obj.msg, gfp);
break;
- case SCTP_CMD_SEND_NEXT_ASCONF:
- sctp_cmd_send_asconf(asoc);
- break;
case SCTP_CMD_PURGE_ASCONF_QUEUE:
sctp_asconf_queue_teardown(asoc);
break;
diff --git a/net/sctp/sm_statefuns.c b/net/sctp/sm_statefuns.c
index c9ae3404b1bb..713a669d2058 100644
--- a/net/sctp/sm_statefuns.c
+++ b/net/sctp/sm_statefuns.c
@@ -3824,6 +3824,29 @@ enum sctp_disposition sctp_sf_do_asconf(struct net *net,
return SCTP_DISPOSITION_CONSUME;
}
+static enum sctp_disposition sctp_send_next_asconf(
+ struct net *net,
+ const struct sctp_endpoint *ep,
+ struct sctp_association *asoc,
+ const union sctp_subtype type,
+ struct sctp_cmd_seq *commands)
+{
+ struct sctp_chunk *asconf;
+ struct list_head *entry;
+
+ if (list_empty(&asoc->addip_chunk_list))
+ return SCTP_DISPOSITION_CONSUME;
+
+ entry = asoc->addip_chunk_list.next;
+ asconf = list_entry(entry, struct sctp_chunk, list);
+
+ list_del_init(entry);
+ sctp_chunk_hold(asconf);
+ asoc->addip_last_asconf = asconf;
+
+ return sctp_sf_do_prm_asconf(net, ep, asoc, type, asconf, commands);
+}
+
/*
* ADDIP Section 4.3 General rules for address manipulation
* When building TLV parameters for the ASCONF Chunk that will add or
@@ -3915,14 +3938,10 @@ enum sctp_disposition sctp_sf_do_asconf_ack(struct net *net,
SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
if (!sctp_process_asconf_ack((struct sctp_association *)asoc,
- 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;
- }
+ asconf_ack))
+ return sctp_send_next_asconf(net, ep,
+ (struct sctp_association *)asoc,
+ type, commands);
abort = sctp_make_abort(asoc, asconf_ack,
sizeof(struct sctp_errhdr));