Hi, There is an other branch where softlockup for nametbl_lock occurs.
tipc_named_rcv() Grabs nametbl_lock tipc_update_nametbl() (publish/withdraw) tipc_node_subscribe()/unsubscribe() tipc_node_write_unlock() << lockup occurs if it needs to process NODE UP/DOWN LINK UP/DOWN, as it grabs nametbl_lock again >> /Partha On 11/21/2016 01:04 PM, Parthasarathy Bhuvaragan wrote: > Hi, > > tipc_nametbl_withdraw() triggers the softlockup as it tries to grab > nametbl_lock twice if the node triggered a TIPC_NOTIFY_LINK_DOWN event > while its is running. The erroneous call chain is: > > tipc_nametbl_withdraw() Grab nametbl_lock > tipc_named_process_backlog() > tipc_update_nametbl() > if (dtype == WITHDRAWAL) tipc_node_unsubscribe() > tipc_node_write_unlock() > if (flags & TIPC_NOTIFY_LINK_DOWN) tipc_nametbl_withdraw() > spin_lock_bh(&tn->nametbl_lock); << Soft Lockup >> > > Three callers which can cause this under module exit: > > Case1: > tipc_exit_net() > tipc_nametbl_withdraw() Grab nametbl_lock > > Case2: > tipc_server_stop() > tipc_conn_kref_release > tipc_sock_release > sock_release() > tipc_release() > tipc_sk_withdraw() > tipc_nametbl_withdraw() > > Case3: > tipc_server_stop() > tipc_conn_kref_release() > kernel_bind() > tipc_bind() > tipc_sk_withdraw() > tipc_nametbl_withdraw() > > I will work on a solution for this. > > What kind of test were you performing when this occurred (linkup/down)? > Do you read link statistics periodically in your tests? > > /Partha > > On 11/21/2016 05:30 AM, John Thompson wrote: >> Hi Partha, >> >> I was doing some some more testing today and have still observed the >> problem (contrary to what I had emailed earlier). >> >> Here is the kernel dump. >> >> <0>NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [Pluggable >> Serve:2221] >> <6>Modules linked in: tipc jitterentropy_rng echainiv drbg >> platform_driver(O) >> <6>CPU: 0 PID: 2221 Comm: Pluggable Serve Tainted: P O >> <6>task: ae54ced0 ti: aec42000 task.ti: aec42000 >> <6>NIP: 8069257c LR: c13ebf50 CTR: 80692540 >> <6>REGS: aec43ad0 TRAP: 0901 Tainted: P O >> <6>MSR: 00029002 <CE,EE,ME> CR: 48002444 XER: 00000000 >> <6> >> <6>GPR00: c13ea408 aec43b80 ae54ced0 a624690c 00000000 a6271d84 a39a60cc >> fffffffd >> <6>GPR08: aeefbbc8 00000001 00000001 00000004 80692540 >> <6>NIP [8069257c] _raw_spin_lock_bh+0x3c/0x70 >> <6>LR [c13ebf50] tipc_nametbl_unsubscribe+0x50/0x120 [tipc] >> <6>Call Trace: >> <6>[aec43b80] [800fa258] check_object+0xc8/0x270 (unreliable) >> <6>[aec43ba0] [c13ea408] tipc_named_reinit+0xf8/0x820 [tipc] >> <6>[aec43bb0] [c13ea6c0] tipc_named_reinit+0x3b0/0x820 [tipc] >> <6>[aec43bd0] [c13f7bbc] tipc_nl_publ_dump+0x50c/0xed0 [tipc] >> <6>[aec43c00] [c13f865c] tipc_conn_sendmsg+0xdc/0x170 [tipc] >> <6>[aec43c30] [c13eacbc] tipc_subscrp_report_overlap+0xbc/0xd0 [tipc] >> <6>[aec43c70] [c13eb27c] tipc_topsrv_stop+0x45c/0x4f0 [tipc] >> <6>[aec43ca0] [c13eb7a8] tipc_nametbl_remove_publ+0x58/0x110 [tipc] >> <6>[aec43cd0] [c13ebc68] tipc_nametbl_withdraw+0x68/0x140 [tipc] >> <6>[aec43d00] [c13f3c34] tipc_nl_node_dump_link+0x1904/0x45d0 [tipc] >> <6>[aec43d30] [c13f4848] tipc_nl_node_dump_link+0x2518/0x45d0 [tipc] > TIPC_CMD_SHOW_LINK_STATS or TIPC_NL_LINK_GET >> <6>[aec43d70] [804f29e0] sock_release+0x30/0xf0 >> <6>[aec43d80] [804f2ab4] sock_close+0x14/0x30 >> <6>[aec43d90] [80105844] __fput+0x94/0x200 >> <6>[aec43db0] [8003dca4] task_work_run+0xd4/0x100 >> <6>[aec43dd0] [80023620] do_exit+0x280/0x980 >> <6>[aec43e10] [80024c48] do_group_exit+0x48/0xb0 >> <6>[aec43e30] [80030344] get_signal+0x244/0x4f0 >> <6>[aec43e80] [80007734] do_signal+0x34/0x1c0 >> <6>[aec43f30] [800079a8] do_notify_resume+0x68/0x80 >> <6>[aec43f40] [8000fa1c] do_user_signal+0x74/0xc4 >> <6>--- interrupt: c00 at 0xf4f3d08 >> <6> LR = 0xf4f3ce8 >> <6>Instruction dump: >> <6>912a0008 39400001 7d201828 2c090000 40820010 7d40192d 40a2fff0 7c2004ac >> <6>2f890000 4dbe0020 7c210b78 81230000 <2f890000> 40befff4 7c421378 >> 7d201828 >> <0>Kernel panic - not syncing: softlockup: hung tasks >> <6>CPU: 0 PID: 2221 Comm: Pluggable Serve Tainted: P O L >> <6>Call Trace: >> <6>[aec43930] [80694e20] dump_stack+0x84/0xb0 (unreliable) >> <6>[aec43940] [80692ca8] panic+0xd8/0x214 >> <6>[aec439a0] [800a0258] watchdog_timer_fn+0x2d8/0x2e0 >> <6>[aec439f0] [8007ae58] __hrtimer_run_queues+0x118/0x1d0 >> <6>[aec43a30] [8007b608] hrtimer_interrupt+0xd8/0x270 >> <6>[aec43a80] [8000983c] __timer_interrupt+0xac/0x1b0 >> <6>[aec43aa0] [80009b70] timer_interrupt+0xb0/0xe0 >> <6>[aec43ac0] [8000f450] ret_from_except+0x0/0x18 >> <6>--- interrupt: 901 at _raw_spin_lock_bh+0x3c/0x70 >> <6> LR = tipc_nametbl_unsubscribe+0x50/0x120 [tipc] >> <6>[aec43b80] [800fa258] check_object+0xc8/0x270 (unreliable) >> <6>[aec43ba0] [c13ea408] tipc_named_reinit+0xf8/0x820 [tipc] >> <6>[aec43bb0] [c13ea6c0] tipc_named_reinit+0x3b0/0x820 [tipc] >> <6>[aec43bd0] [c13f7bbc] tipc_nl_publ_dump+0x50c/0xed0 [tipc] >> <6>[aec43c00] [c13f865c] tipc_conn_sendmsg+0xdc/0x170 [tipc] >> <6>[aec43c30] [c13eacbc] tipc_subscrp_report_overlap+0xbc/0xd0 [tipc] >> <6>[aec43c70] [c13eb27c] tipc_topsrv_stop+0x45c/0x4f0 [tipc] >> <6>[aec43ca0] [c13eb7a8] tipc_nametbl_remove_publ+0x58/0x110 [tipc] >> <6>[aec43cd0] [c13ebc68] tipc_nametbl_withdraw+0x68/0x140 [tipc] >> <6>[aec43d00] [c13f3c34] tipc_nl_node_dump_link+0x1904/0x45d0 [tipc] >> <6>[aec43d30] [c13f4848] tipc_nl_node_dump_link+0x2518/0x45d0 [tipc] >> <6>[aec43d70] [804f29e0] sock_release+0x30/0xf0 >> <6>[aec43d80] [804f2ab4] sock_close+0x14/0x30 >> <6>[aec43d90] [80105844] __fput+0x94/0x200 >> <6>[aec43db0] [8003dca4] task_work_run+0xd4/0x100 >> <6>[aec43dd0] [80023620] do_exit+0x280/0x980 >> <6>[aec43e10] [80024c48] do_group_exit+0x48/0xb0 >> <6>[aec43e30] [80030344] get_signal+0x244/0x4f0 >> <6>[aec43e80] [80007734] do_signal+0x34/0x1c0 >> <6>[aec43f30] [800079a8] do_notify_resume+0x68/0x80 >> <6>[aec43f40] [8000fa1c] do_user_signal+0x74/0xc4 >> <6>--- interrupt: c00 at 0xf4f3d08 >> <6> LR = 0xf4f3ce8 >> >> >> On Mon, Nov 21, 2016 at 9:59 AM, John Thompson <thompa....@gmail.com >> <mailto:thompa....@gmail.com>> wrote: >> >> Hi Partha, >> >> In my testing over the weekend the patch performed well - I didn't >> see any kernel dumps due to this issue. >> >> Thanks for the quick response. >> JT >> >> >> On Fri, Nov 18, 2016 at 10:34 AM, John Thompson >> <thompa....@gmail.com <mailto:thompa....@gmail.com>> wrote: >> >> Hi, >> >> I will be able to have some test results by the start of next >> week on the first patch. >> >> Regards, >> JT >> >> >> On Thu, Nov 17, 2016 at 11:27 PM, Ying Xue >> <ying....@windriver.com <mailto:ying....@windriver.com>> wrote: >> >> On 11/17/2016 07:04 AM, John Thompson wrote: >> >> Hi Partha / Ying, >> >> I will try out the patch and let you know how it goes. >> I also note about providing the other CPU core dumps - >> in one of my cases I >> didn't have them but in others I did but >> they were interleaved and so were difficult to interpret. >> >> >> Thanks, it's unnecessary for us to collect more logs as its >> soft lockup scenario should be just what Partha described. >> >> Regards, >> Ying >> >> >> >> Thanks for getting a patch together so quickly. >> >> JT >> >> On Wed, Nov 16, 2016 at 10:23 PM, Parthasarathy Bhuvaragan < >> parthasarathy.bhuvara...@ericsson.com >> <mailto:parthasarathy.bhuvara...@ericsson.com>> wrote: >> >> Hi Ying / John, >> >> The soft lock is the call chain of >> tipc_nametbl_withdraw(), when it >> performs the tipc_conn_kref_release() as it tries to >> grab nametbl_lock >> again while holding it already. >> >> tipc_nametbl_withdraw >> spin_lock_bh(&tn->nametbl_lock); >> tipc_nametbl_remove_publ >> spin_lock_bh(&seq->lock); >> tipc_nameseq_remove_publ >> tipc_subscrp_report_overlap >> tipc_subscrp_send_event >> tipc_conn_sendmsg >> >> << Here, the (test_bit(CF_CONNECTED, &con->flags)) >> Fails, leading to the >> else case where do do a conn_put() and that triggers >> the cleanup as >> refcount reached 0. Leading the call chain below : >> >> tipc_conn_kref_release >> tipc_sock_release >> tipc_conn_release >> tipc_subscrb_delete >> tipc_subscrp_delete >> tipc_nametbl_unsubscribe >> spin_lock_bh(&tn->nametbl_lock); >> << !! Soft Lockup >> >> >> One cause is that tipc_exit_net() calls first calls >> tipc_topsrv_stop() and >> then tipc_nametbl_withdraw() in scope of >> tipc_net_stop(). >> >> The above chain will only occur in a narrow window >> for a given connection: >> CPU#1: >> tipc_nametbl_withdraw() manages to perform >> tipc_conn_lookup() and steps >> the refcount to 2, while in CPU#2 the following occurs: >> CPU#2: >> tipc_server_stop() calls tipc_close_conn(con). This >> performs a conn_put() >> decrementing refcount to 1. >> Now, CPU#1 continues and detects that the connection >> is not CF_CONNECTED >> and does a conn_put(), triggering the release callback. >> >> Before commit 333f796235a527, the above wont happen. >> >> /Partha >> >> >> On 11/15/2016 04:11 PM, Xue, Ying wrote: >> >> Hi John, >> >> Regarding the stack trace you provided below, I >> get the two potential >> call chains: >> >> tipc_nametbl_withdraw >> spin_lock_bh(&tn->nametbl_lock); >> tipc_nametbl_remove_publ >> spin_lock_bh(&seq->lock); >> tipc_nameseq_remove_publ >> tipc_subscrp_report_overlap >> tipc_subscrp_send_event >> tipc_conn_sendmsg >> spin_lock_bh(&con->outqueue_lock); >> list_add_tail(&e->list, >> &con->outqueue); >> >> >> tipc_topsrv_stop >> tipc_server_stop >> tipc_close_conn >> kernel_sock_shutdown >> tipc_subscrb_delete >> spin_lock_bh(&subscriber->lock); >> tipc_nametbl_unsubscribe(sub); >> spin_lock_bh(&tn->nametbl_lock); >> >> Although I suspect this is a revert lock issue >> leading to the soft >> lockup, I am still unable to understand which >> lock together with >> nametbl_lock is taken reversely on the two >> different paths above. >> However, you just gave us the log printed on >> CPU#2, but the logs >> outputted by other cores are also important. So >> if possible, please share >> them with us. >> >> By the way, I agree with you, and it seems that >> commit 333f796235a527 is >> related to the soft lockup. >> >> Regards, >> Ying >> >> -----Original Message----- >> From: John Thompson [mailto:thompa....@gmail.com >> <mailto:thompa....@gmail.com>] >> Sent: Tuesday, November 15, 2016 8:01 AM >> To: tipc-discussion@lists.sourceforge.net >> <mailto:tipc-discussion@lists.sourceforge.net> >> Subject: [tipc-discussion] v4.7: soft lockup >> when releasing a socket >> >> Hi, >> >> I am seeing an occasional kernel soft lockup. I >> have TIPC v4.7 and the >> kernel dump occurs when the system is going down >> for a reboot. >> >> The kernel dump is: >> >> <0>NMI watchdog: BUG: soft lockup - CPU#2 stuck >> for 23s! [exfx:1474] >> <6>Modules linked in: tipc jitterentropy_rng >> echainiv drbg >> platform_driver(O) ipifwd(PO) >> ... >> <6> >> <6>GPR00: c15333e8 a4e0fb80 a4ee3600 a51748ac >> 00000000 ae475024 a537feec >> fffffffd >> <6>GPR08: a2197408 00000001 00000001 00000004 >> 80691c00 <6>NIP [80691c40] >> _raw_spin_lock_bh+0x40/0x70 <6>LR [c1534f30] >> tipc_nametbl_unsubscribe+0x50/0x120 >> [tipc] <6>Call Trace: >> <6>[a4e0fba0] [c15333e8] >> tipc_named_reinit+0xf8/0x820 [tipc] >> <6>[a4e0fbb0] [c15336a0] >> tipc_named_reinit+0x3b0/0x820 [tipc] <6>[a4e0fbd0] >> [c1540bac] tipc_nl_publ_dump+0x50c/0xed0 [tipc] >> <6>[a4e0fc00] [c154164c] >> tipc_conn_sendmsg+0xdc/0x170 [tipc] >> <6>[a4e0fc30] [c1533c9c] >> tipc_subscrp_report_overlap+0xbc/0xd0 [tipc] >> <6>[a4e0fc70] [c153425c] >> tipc_topsrv_stop+0x45c/0x4f0 [tipc] >> <6>[a4e0fca0] [c1534788] >> tipc_nametbl_remove_publ+0x58/0x110 [tipc] >> <6>[a4e0fcd0] [c1534c48] >> tipc_nametbl_withdraw+0x68/0x140 [tipc] >> <6>[a4e0fd00] [c153cc24] >> tipc_nl_node_dump_link+0x1904/0x45d0 [tipc] >> <6>[a4e0fd30] [c153d838] >> tipc_nl_node_dump_link+0x2518/0x45d0 [tipc] >> <6>[a4e0fd70] [804f2870] >> sock_release+0x30/0xf0 <6>[a4e0fd80] [804f2944] >> sock_close+0x14/0x30 >> <6>[a4e0fd90] [80105844] __fput+0x94/0x200 >> <6>[a4e0fdb0] [8003dca4] >> task_work_run+0xd4/0x100 <6>[a4e0fdd0] >> [80023620] do_exit+0x280/0x980 >> <6>[a4e0fe10] [80024c48] do_group_exit+0x48/0xb0 >> <6>[a4e0fe30] [80030344] >> get_signal+0x244/0x4f0 <6>[a4e0fe80] [80007734] >> do_signal+0x34/0x1c0 >> <6>[a4e0ff30] [800079a8] >> do_notify_resume+0x68/0x80 <6>[a4e0ff40] >> [8000fa1c] do_user_signal+0x74/0xc4 >> >> >> From the stack dump it looks like >> tipc_named_reinit is trying to >> >> >> acquire nametbl_lock. >> >> From looking at the call chain I can see that >> tipc_conn_sendmsg can >> >> >> send up calling conn_put >> >> which will go on and call the tipc_named_reinit >> via tipc_sock_release. >> >> As tipc_nametbl_withdraw (from the stack dump) >> has already acquired the >> nametbl_lock, tipc_named_reinit >> >> cannot get it and so the process hangs. >> >> >> The call to tipc_sock_release (added in Commit >> 333f796235a527 >> >> <http://git.atlnz.lc/cgit/cgit.cgi/upstream_imports/linux- >> >> <http://git.atlnz.lc/cgit/cgit.cgi/upstream_imports/linux-> >> >> stable.git/commit/?id=333f796235a52727db7e0a13888045f3aa3d5335>) >> seems to have changed the behaviour >> >> such that it tries to do a lot more when >> shutting the connection down. >> >> >> If there is other information I can provide >> please let me know. >> >> Regards, >> >> John >> >> ------------------------------------------------------------ >> ------------------ >> _______________________________________________ >> tipc-discussion mailing list >> tipc-discussion@lists.sourceforge.net >> <mailto:tipc-discussion@lists.sourceforge.net> >> >> https://lists.sourceforge.net/lists/listinfo/tipc-discussion >> >> <https://lists.sourceforge.net/lists/listinfo/tipc-discussion> >> >> ------------------------------------------------------------ >> ------------------ >> _______________________________________________ >> tipc-discussion mailing list >> tipc-discussion@lists.sourceforge.net >> <mailto:tipc-discussion@lists.sourceforge.net> >> >> https://lists.sourceforge.net/lists/listinfo/tipc-discussion >> >> <https://lists.sourceforge.net/lists/listinfo/tipc-discussion> >> >> >> >> >> ------------------------------------------------------------------------------ >> _______________________________________________ >> tipc-discussion mailing list >> tipc-discussion@lists.sourceforge.net >> <mailto:tipc-discussion@lists.sourceforge.net> >> https://lists.sourceforge.net/lists/listinfo/tipc-discussion >> >> <https://lists.sourceforge.net/lists/listinfo/tipc-discussion> >> >> >> >> >> > > ------------------------------------------------------------------------------ > _______________________________________________ > tipc-discussion mailing list > tipc-discussion@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/tipc-discussion > ------------------------------------------------------------------------------ _______________________________________________ tipc-discussion mailing list tipc-discussion@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/tipc-discussion