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Date: Thu, 29 Apr 2010 15:09:20 +0100
From: Shuaijun Zhang <szhang@...earch.ait.ie>
To: Vlad Yasevich <vladislav.yasevich@...com>
CC: netdev@...r.kernel.org, davem@...emloft.net,
linux-sctp@...r.kernel.org, Yuansong Qiao <ysqiao@...earch.ait.ie>
Subject: Re: [PATCH 5/5] sctp: Fix oops when sending queued ASCONF chunks
Vlad Yasevich wrote:
> 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
>
According to the call trace below, it seems that our modification did
not take affect.
sctp_primitive_ASCONF should be invoked after sctp_side_effects().
Our code fixed the same problem in kernel 2.6.27.28.
Not sure about the difference between 2.6.34-rc4 kernel and 2.6.27.28
kernel.
> 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] <--- sctp_side_effects() should show up here before send next asconf
> [<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@...fujitsu.com>
> Signed-off-by: Yuansong Qiao <ysqiao@...earch.ait.ie>
> Signed-off-by: Shuaijun Zhang <szhang@...earch.ait.ie>
> Signed-off-by: Vlad Yasevich <vladislav.yasevich@...com>
> ---
> include/net/sctp/command.h | 1 +
> net/sctp/sm_make_chunk.c | 15 ---------------
> net/sctp/sm_sideeffect.c | 26 ++++++++++++++++++++++++++
> net/sctp/sm_statefuns.c | 8 +++++++-
> 4 files changed, 34 insertions(+), 16 deletions(-)
>
> diff --git a/include/net/sctp/command.h b/include/net/sctp/command.h
> index 8be5135..2c55a7e 100644
> --- a/include/net/sctp/command.h
> +++ b/include/net/sctp/command.h
> @@ -107,6 +107,7 @@ typedef enum {
> 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_LAST
> } sctp_verb_t;
>
> diff --git a/net/sctp/sm_make_chunk.c b/net/sctp/sm_make_chunk.c
> index f6fc5c1..0fd5b4c 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 4c5bed9..d5ae450 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 abf601a..24b2cd5 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));
>
--
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