rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (10499 ticks this GP) idle=9dd/1/0x4000000000000000 softirq=16902/16902 fqs=38 (t=10500 jiffies g=22173 q=323) rcu: rcu_preempt kthread starved for 10419 jiffies! g22173 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 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:28696 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4955 [inline] __schedule+0x940/0x26f0 kernel/sched/core.c:6236 schedule+0xd3/0x270 kernel/sched/core.c:6315 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x186/0x810 kernel/rcu/tree.c:1955 rcu_gp_kthread+0x1de/0x320 kernel/rcu/tree.c:2128 kthread+0x405/0x4f0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 10610 Comm: syz-executor.0 Not tainted 5.15.0-rc2-next-20210921-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:rcu_lockdep_current_cpu_online+0x7/0x150 kernel/rcu/tree.c:1166 Code: 4c 24 30 4c 8b 54 24 28 48 8b 54 24 20 48 8b 44 24 18 e9 41 fe ff ff 66 66 2e 0f 1f 84 00 00 00 00 00 90 65 8b 15 09 04 a0 7e <81> e2 00 00 f0 00 b8 01 00 00 00 75 0a 8b 15 ba 75 0c 0c 85 d2 75 RSP: 0018:ffffc900046df5f0 EFLAGS: 00000202 RAX: 0000000000000001 RBX: 1ffff920008dbec3 RCX: ffffffff8161de24 RDX: 0000000000000202 RSI: 0000000000000004 RDI: ffff8880b9c32a08 RBP: 0000000000000001 R08: 0000000000000000 R09: ffff8880b9c32a0b R10: ffffed1017386541 R11: 0000000000000000 R12: 0000000000000001 R13: 0000000000000000 R14: ffff888081348c60 R15: 0000000000000000 FS: 00007f0bc018e700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2dc29000 CR3: 000000001ecd7000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: rcu_read_lock_held_common kernel/rcu/update.c:112 [inline] rcu_read_lock_held_common kernel/rcu/update.c:102 [inline] rcu_read_lock_sched_held+0x25/0x70 kernel/rcu/update.c:123 trace_lock_acquire include/trace/events/lock.h:13 [inline] lock_acquire+0x442/0x510 kernel/locking/lockdep.c:5596 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline] _raw_spin_lock_bh+0x2f/0x40 kernel/locking/spinlock.c:178 spin_lock_bh include/linux/spinlock.h:373 [inline] lock_sock_nested+0x5d/0xf0 net/core/sock.c:3186 lock_sock include/net/sock.h:1612 [inline] mptcp_wait_data net/mptcp/protocol.c:1770 [inline] mptcp_recvmsg+0x1047/0x27b0 net/mptcp/protocol.c:2080 inet6_recvmsg+0x11b/0x5e0 net/ipv6/af_inet6.c:659 sock_recvmsg_nosec net/socket.c:944 [inline] ____sys_recvmsg+0x527/0x600 net/socket.c:2626 ___sys_recvmsg+0x127/0x200 net/socket.c:2670 do_recvmmsg+0x24d/0x6d0 net/socket.c:2764 __sys_recvmmsg net/socket.c:2843 [inline] __do_sys_recvmmsg net/socket.c:2866 [inline] __se_sys_recvmmsg net/socket.c:2859 [inline] __x64_sys_recvmmsg+0x20b/0x260 net/socket.c:2859 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: 0033:0x7f0bc2c17739 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:00007f0bc018e188 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f0bc2d1bf80 RCX: 00007f0bc2c17739 RDX: 0000000000000002 RSI: 00000000200017c0 RDI: 0000000000000003 RBP: 00007f0bc2c71cc4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000100 R11: 0000000000000246 R12: 00007f0bc2d1bf80 R13: 00007fff21552f8f R14: 00007f0bc018e300 R15: 0000000000022000 NMI backtrace for cpu 1 CPU: 1 PID: 10594 Comm: syz-executor.4 Not tainted 5.15.0-rc2-next-20210921-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:106 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x1ae/0x220 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_dump_cpu_stacks+0x25e/0x3f0 kernel/rcu/tree_stall.h:343 print_cpu_stall kernel/rcu/tree_stall.h:627 [inline] check_cpu_stall kernel/rcu/tree_stall.h:711 [inline] rcu_pending kernel/rcu/tree.c:3878 [inline] rcu_sched_clock_irq.cold+0x9d/0x746 kernel/rcu/tree.c:2597 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:1428 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:lock_acquire+0x1ef/0x510 kernel/locking/lockdep.c:5593 Code: 77 a6 7e 83 f8 01 0f 85 b4 02 00 00 9c 58 f6 c4 02 0f 85 9f 02 00 00 48 83 7c 24 08 00 74 01 fb 48 b8 00 00 00 00 00 fc ff df <48> 01 c3 48 c7 03 00 00 00 00 48 c7 43 08 00 00 00 00 48 8b 84 24 RSP: 0018:ffffc9000467f618 EFLAGS: 00000206 RAX: dffffc0000000000 RBX: 1ffff920008cfec5 RCX: ffffffff815b2f8f RDX: 1ffff11006e2dc2c RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff8fd029cf R10: fffffbfff1fa0539 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: ffff8880260ea6a0 R15: 0000000000000000 lock_sock_fast+0x36/0x100 net/core/sock.c:3229 mptcp_subflow_cleanup_rbuf net/mptcp/protocol.c:465 [inline] mptcp_cleanup_rbuf net/mptcp/protocol.c:499 [inline] mptcp_recvmsg+0xad3/0x27b0 net/mptcp/protocol.c:2027 inet6_recvmsg+0x11b/0x5e0 net/ipv6/af_inet6.c:659 sock_recvmsg_nosec net/socket.c:944 [inline] ____sys_recvmsg+0x527/0x600 net/socket.c:2626 ___sys_recvmsg+0x127/0x200 net/socket.c:2670 do_recvmmsg+0x24d/0x6d0 net/socket.c:2764 __sys_recvmmsg net/socket.c:2843 [inline] __do_sys_recvmmsg net/socket.c:2866 [inline] __se_sys_recvmmsg net/socket.c:2859 [inline] __x64_sys_recvmmsg+0x20b/0x260 net/socket.c:2859 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: 0033:0x7f0997722739 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:00007f0994c99188 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f0997826f80 RCX: 00007f0997722739 RDX: 0000000000000002 RSI: 00000000200017c0 RDI: 0000000000000003 RBP: 00007f099777ccc4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000100 R11: 0000000000000246 R12: 00007f0997826f80 R13: 00007ffc162987df R14: 00007f0994c99300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: 4c 24 30 rex.WR and $0x30,%al 3: 4c 8b 54 24 28 mov 0x28(%rsp),%r10 8: 48 8b 54 24 20 mov 0x20(%rsp),%rdx d: 48 8b 44 24 18 mov 0x18(%rsp),%rax 12: e9 41 fe ff ff jmpq 0xfffffe58 17: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1) 1e: 00 00 00 00 22: 90 nop 23: 65 8b 15 09 04 a0 7e mov %gs:0x7ea00409(%rip),%edx # 0x7ea00433 * 2a: 81 e2 00 00 f0 00 and $0xf00000,%edx <-- trapping instruction 30: b8 01 00 00 00 mov $0x1,%eax 35: 75 0a jne 0x41 37: 8b 15 ba 75 0c 0c mov 0xc0c75ba(%rip),%edx # 0xc0c75f7 3d: 85 d2 test %edx,%edx 3f: 75 .byte 0x75