From: Xin Long lucien.xin@gmail.com
[ Upstream commit fbd019737d71e405f86549fd738f81e2ff3dd073 ]
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- include/net/sctp/command.h | 1 - net/sctp/sm_sideeffect.c | 29 ----------------------------- net/sctp/sm_statefuns.c | 35 +++++++++++++++++++++++++++-------- 3 files changed, 27 insertions(+), 38 deletions(-)
--- 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 --- a/net/sctp/sm_sideeffect.c +++ b/net/sctp/sm_sideeffect.c @@ -1112,32 +1112,6 @@ static void sctp_cmd_send_msg(struct sct }
-/* 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 sct } 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; --- a/net/sctp/sm_statefuns.c +++ b/net/sctp/sm_statefuns.c @@ -3824,6 +3824,29 @@ enum sctp_disposition sctp_sf_do_asconf( 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_ 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));