On Wed, May 16, 2018 at 2:12 PM, Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote: > On Wed, May 16, 2018 at 1:02 PM, Xin Long <lucien.xin@xxxxxxxxx> wrote: >>>> <syzbot+ff0b569fb5111dcd1a36@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: >>>>> Hello, >>>>> >>>>> syzbot found the following crash on: >>>>> >>>>> HEAD commit: 961423f9fcbc Merge branch 'sctp-Introduce-sctp_flush_ctx' >>>>> git tree: net-next >>>>> console output: https://syzkaller.appspot.com/x/log.txt?x=1366aea7800000 >>>>> kernel config: https://syzkaller.appspot.com/x/.config?x=51fb0a6913f757db >>>>> dashboard link: https://syzkaller.appspot.com/bug?extid=ff0b569fb5111dcd1a36 >>>>> compiler: gcc (GCC) 8.0.1 20180413 (experimental) >>>>> >>>>> Unfortunately, I don't have any reproducer for this crash yet. >>>>> >>>>> IMPORTANT: if you fix the bug, please add the following tag to the commit: >>>>> Reported-by: syzbot+ff0b569fb5111dcd1a36@xxxxxxxxxxxxxxxxxxxxxxxxx >>>>> >>>>> INFO: rcu_sched self-detected stall on CPU >>>>> 0-....: (1 GPs behind) idle=dae/1/4611686018427387908 >>>>> softirq=93090/93091 fqs=30902 >>>>> (t=125000 jiffies g=51107 c=51106 q=972) >>>>> NMI backtrace for cpu 0 >>>>> CPU: 0 PID: 24668 Comm: syz-executor6 Not tainted 4.17.0-rc4+ #44 >>>>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS >>>>> Google 01/01/2011 >>>>> Call Trace: >>>>> <IRQ> >>>>> __dump_stack lib/dump_stack.c:77 [inline] >>>>> dump_stack+0x1b9/0x294 lib/dump_stack.c:113 >>>>> nmi_cpu_backtrace.cold.4+0x19/0xce lib/nmi_backtrace.c:103 >>>>> nmi_trigger_cpumask_backtrace+0x151/0x192 lib/nmi_backtrace.c:62 >>>>> arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 >>>>> trigger_single_cpu_backtrace include/linux/nmi.h:156 [inline] >>>>> rcu_dump_cpu_stacks+0x175/0x1c2 kernel/rcu/tree.c:1376 >>>>> print_cpu_stall kernel/rcu/tree.c:1525 [inline] >>>>> check_cpu_stall.isra.61.cold.80+0x36c/0x59a kernel/rcu/tree.c:1593 >>>>> __rcu_pending kernel/rcu/tree.c:3356 [inline] >>>>> rcu_pending kernel/rcu/tree.c:3401 [inline] >>>>> rcu_check_callbacks+0x21b/0xad0 kernel/rcu/tree.c:2763 >>>>> update_process_times+0x2d/0x70 kernel/time/timer.c:1636 >>>>> tick_sched_handle+0x9f/0x180 kernel/time/tick-sched.c:164 >>>>> tick_sched_timer+0x45/0x130 kernel/time/tick-sched.c:1274 >>>>> __run_hrtimer kernel/time/hrtimer.c:1398 [inline] >>>>> __hrtimer_run_queues+0x3e3/0x10a0 kernel/time/hrtimer.c:1460 >>>>> hrtimer_interrupt+0x2f3/0x750 kernel/time/hrtimer.c:1518 >>>>> local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1025 [inline] >>>>> smp_apic_timer_interrupt+0x15d/0x710 arch/x86/kernel/apic/apic.c:1050 >>>>> apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:863 >>>>> RIP: 0010:sctp_v6_xmit+0x259/0x6b0 net/sctp/ipv6.c:219 >>>>> RSP: 0018:ffff8801dae068e8 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 >>>>> RAX: 0000000000000007 RBX: ffff8801bb7ec800 RCX: ffffffff86f1b345 >>>>> RDX: 0000000000000000 RSI: ffffffff86f1b381 RDI: ffff8801b73d97c4 >>>>> RBP: ffff8801dae06988 R08: ffff88019505c300 R09: ffffed003b5c46c2 >>>>> R10: ffffed003b5c46c2 R11: ffff8801dae23613 R12: ffff88011fd57300 >>>>> R13: ffff8801bb7ecec8 R14: 0000000000000029 R15: 0000000000000002 >>>>> sctp_packet_transmit+0x26f6/0x3ba0 net/sctp/output.c:642 >>>>> sctp_outq_flush_transports net/sctp/outqueue.c:1164 [inline] >>>>> sctp_outq_flush+0x5f5/0x3430 net/sctp/outqueue.c:1212 >>>>> sctp_outq_uncork+0x6a/0x80 net/sctp/outqueue.c:776 >>>>> sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1820 [inline] >>>>> sctp_side_effects net/sctp/sm_sideeffect.c:1220 [inline] >>>>> sctp_do_sm+0x596/0x7160 net/sctp/sm_sideeffect.c:1191 >>>>> sctp_generate_heartbeat_event+0x218/0x450 net/sctp/sm_sideeffect.c:406 >>>> Shocks, this timer event again. Can we try to minimize the repo.syz and >>>> get a short script, not neccessary to reproduce the issue 100%. we need >>>> to know what it was doing when this happened. >>>> >>>> Thanks. >>> >>> It's possible to reply the whole log from console output following >>> these instructions: >>> https://github.com/google/syzkaller/blob/master/docs/executing_syzkaller_programs.md >> Thanks, it's running now. >> Usually how long will it take to finish running this 5000-line log? > > If you run with -repeat=0 then it will run infinitely repeating the > log again and again. If you see: > > parsed 1000 programs > ... > executed 5000 programs > > then it looped 5 times already. You can run with -repeat=10. > > syzbot has tried replaying the log, but for some reason it wasn't able > to reproduce the crash (maybe accumulated state, or maybe it crashed > in a different way). You can also try logs from other sctp hangs. #syz fix: sctp: not allow to set rto_min with a value below 200 msecs -- To unsubscribe from this list: send the line "unsubscribe linux-sctp" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
