rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): (detected by 1, t=10502 jiffies, g=140673, q=810) rcu: All QSes seen, last rcu_preempt kthread activity 10491 (4295035499-4295025008), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10491 jiffies! g140673 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:R running task stack:28864 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4681 [inline] __schedule+0x93a/0x26f0 kernel/sched/core.c:5938 schedule+0xd3/0x270 kernel/sched/core.c:6017 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1881 rcu_gp_fqs_loop kernel/rcu/tree.c:1996 [inline] rcu_gp_kthread+0xd34/0x1980 kernel/rcu/tree.c:2169 kthread+0x3e5/0x4d0 kernel/kthread.c:319 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 1 CPU: 1 PID: 30903 Comm: syz-executor.4 Not tainted 5.14.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:105 nmi_cpu_backtrace.cold+0x44/0xd7 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1b3/0x230 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_check_gp_kthread_starvation.cold+0x1d1/0x1d6 kernel/rcu/tree_stall.h:479 print_other_cpu_stall kernel/rcu/tree_stall.h:584 [inline] check_cpu_stall kernel/rcu/tree_stall.h:709 [inline] rcu_pending kernel/rcu/tree.c:3922 [inline] rcu_sched_clock_irq+0x2001/0x20c0 kernel/rcu/tree.c:2641 update_process_times+0x16d/0x200 kernel/time/timer.c:1785 tick_sched_handle+0x9b/0x180 kernel/time/tick-sched.c:226 tick_sched_timer+0x1b0/0x2d0 kernel/time/tick-sched.c:1421 __run_hrtimer kernel/time/hrtimer.c:1537 [inline] __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1601 hrtimer_interrupt+0x330/0xa00 kernel/time/hrtimer.c:1663 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1089 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1106 sysvec_apic_timer_interrupt+0x40/0xc0 arch/x86/kernel/apic/apic.c:1100 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:lock_timer_base+0x0/0x1f0 kernel/time/timer.c:932 Code: e6 74 57 00 eb aa 48 89 df e8 dc 74 57 00 eb d2 66 2e 0f 1f 84 00 00 00 00 00 e8 bb 3a 11 00 0f 0b c3 0f 1f 84 00 00 00 00 00 <41> 57 48 8d 47 20 41 56 49 89 c6 41 55 49 c1 ee 03 49 89 fd 41 54 RSP: 0018:ffffc90000dc0c18 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000100 RDX: ffff888020763880 RSI: ffffc90000dc0c80 RDI: ffff88803264ac10 RBP: ffff88803264ac10 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff8165096a R11: 0000000000000000 R12: ffff88803264ac10 R13: 1ffff920001b81a8 R14: ffffffff8735a690 R15: ffff88803264ac18 __mod_timer+0x398/0xe30 kernel/time/timer.c:1019 call_timer_fn+0x1a5/0x6b0 kernel/time/timer.c:1421 expire_timers kernel/time/timer.c:1466 [inline] __run_timers.part.0+0x675/0xa20 kernel/time/timer.c:1734 __run_timers kernel/time/timer.c:1715 [inline] run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1747 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558 invoke_softirq kernel/softirq.c:432 [inline] __irq_exit_rcu+0x16e/0x1c0 kernel/softirq.c:636 irq_exit_rcu+0x5/0x20 kernel/softirq.c:648 sysvec_apic_timer_interrupt+0x93/0xc0 arch/x86/kernel/apic/apic.c:1100 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:163 [inline] RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x60 kernel/kcov.c:197 Code: 01 f0 4d 89 03 e9 63 fd ff ff b9 ff ff ff ff ba 08 00 00 00 4d 8b 03 48 0f bd ca 49 8b 45 00 48 63 c9 e9 64 ff ff ff 0f 1f 00 <65> 8b 05 f9 46 8c 7e 89 c1 48 8b 34 24 81 e1 00 01 00 00 65 48 8b RSP: 0018:ffffc9000367f6b0 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffffc9000367f770 RCX: ffff888020763880 RDX: 0000000000000000 RSI: ffff888020763880 RDI: 0000000000000003 RBP: ffff888015e097a0 R08: 0000000000000000 R09: 00000000000022e1 R10: ffffffff884d02b5 R11: 00000000000022e1 R12: 00000000000022e1 R13: 00000000000022e1 R14: ffffffff8d3a7440 R15: 0000000000000001 sctp_v4_cmp_addr net/sctp/protocol.c:305 [inline] sctp_v4_cmp_addr+0x112/0x1d0 net/sctp/protocol.c:298 sctp_bind_addr_state+0x103/0x1d0 net/sctp/bind_addr.c:407 sctp_copy_local_addr_list+0x1fe/0x4f0 net/sctp/protocol.c:163 sctp_copy_one_addr net/sctp/bind_addr.c:460 [inline] sctp_bind_addr_copy+0xde/0x460 net/sctp/bind_addr.c:56 sctp_connect_new_asoc+0x1cd/0x770 net/sctp/socket.c:1092 sctp_sendmsg_new_asoc net/sctp/socket.c:1690 [inline] sctp_sendmsg+0x13bc/0x1d30 net/sctp/socket.c:2000 inet_sendmsg+0x99/0xe0 net/ipv4/af_inet.c:821 sock_sendmsg_nosec net/socket.c:703 [inline] sock_sendmsg+0xcf/0x120 net/socket.c:723 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2392 ___sys_sendmsg+0xf3/0x170 net/socket.c:2446 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2475 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4665e9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f4e92333188 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665e9 RDX: 0000000000040000 RSI: 00000000200001c0 RDI: 0000000000000005 RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80 R13: 0000000000a9fb1f R14: 00007f4e92333300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: e6 74 out %al,$0x74 2: 57 push %rdi 3: 00 eb add %ch,%bl 5: aa stos %al,%es:(%rdi) 6: 48 89 df mov %rbx,%rdi 9: e8 dc 74 57 00 callq 0x5774ea e: eb d2 jmp 0xffffffe2 10: 66 2e 0f 1f 84 00 00 nopw %cs:0x0(%rax,%rax,1) 17: 00 00 00 1a: e8 bb 3a 11 00 callq 0x113ada 1f: 0f 0b ud2 21: c3 retq 22: 0f 1f 84 00 00 00 00 nopl 0x0(%rax,%rax,1) 29: 00 * 2a: 41 57 push %r15 <-- trapping instruction 2c: 48 8d 47 20 lea 0x20(%rdi),%rax 30: 41 56 push %r14 32: 49 89 c6 mov %rax,%r14 35: 41 55 push %r13 37: 49 c1 ee 03 shr $0x3,%r14 3b: 49 89 fd mov %rdi,%r13 3e: 41 54 push %r12