rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 0-...!: (1 GPs behind) idle=bfd/1/0x4000000000000000 softirq=230835/230836 fqs=2 (t=10502 jiffies g=454269 q=28) rcu: rcu_preempt kthread starved for 10499 jiffies! g454269 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: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:1966 rcu_gp_kthread+0x1de/0x320 kernel/rcu/tree.c:2139 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 21410 Comm: syz-executor.1 Not tainted 5.15.0-rc3-next-20211001-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:variable_test_bit arch/x86/include/asm/bitops.h:214 [inline] RIP: 0010:test_bit include/asm-generic/bitops/instrumented-non-atomic.h:135 [inline] RIP: 0010:hlock_class kernel/locking/lockdep.c:199 [inline] RIP: 0010:__lock_acquire+0xbc2/0x54a0 kernel/locking/lockdep.c:5024 Code: 74 61 00 41 0f b7 5c 24 20 66 81 e3 ff 1f 0f b7 db be 08 00 00 00 48 89 d8 48 c1 f8 06 48 8d 3c c5 40 79 d1 8f e8 7e 77 61 00 <48> 0f a3 1d 26 1f 76 0e 0f 83 f1 0b 00 00 48 8d 1c 5b 48 c1 e3 06 RSP: 0018:ffffc9000450f4e8 EFLAGS: 00000046 RAX: 0000000000000001 RBX: 000000000000063b RCX: ffffffff815b5a12 RDX: fffffbfff1fa2f41 RSI: 0000000000000008 RDI: ffffffff8fd17a00 RBP: ffff8880182e618a R08: 0000000000000000 R09: ffffffff8fd17a07 R10: fffffbfff1fa2f40 R11: 0000000000000000 R12: ffff8880182e6168 R13: ffff8880182e5700 R14: 0000000000000001 R15: ffffffffffffffff FS: 00007f574f256700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2ce25000 CR3: 000000007ef81000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lock_acquire kernel/locking/lockdep.c:5637 [inline] lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5602 lock_sock_nested+0x2f/0xf0 net/core/sock.c:3272 lock_sock include/net/sock.h:1636 [inline] mptcp_wait_data net/mptcp/protocol.c:1812 [inline] mptcp_recvmsg+0x1087/0x27b0 net/mptcp/protocol.c:2122 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: 0033:0x7f5751d008d9 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:00007f574f256188 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f5751e05020 RCX: 00007f5751d008d9 RDX: 0000000000000002 RSI: 00000000200017c0 RDI: 0000000000000004 RBP: 00007f5751d5acb4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000100 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fffe636008f R14: 00007f574f256300 R15: 0000000000022000 NMI backtrace for cpu 0 CPU: 0 PID: 21403 Comm: syz-executor.4 Not tainted 5.15.0-rc3-next-20211001-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:604 [inline] check_cpu_stall kernel/rcu/tree_stall.h:688 [inline] rcu_pending kernel/rcu/tree.c:3889 [inline] rcu_sched_clock_irq.cold+0x9d/0x746 kernel/rcu/tree.c:2608 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:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x38/0x70 kernel/locking/spinlock.c:194 Code: 74 24 10 e8 1a ad 25 f8 48 89 ef e8 62 23 26 f8 81 e3 00 02 00 00 75 25 9c 58 f6 c4 02 75 2d 48 85 db 74 01 fb bf 01 00 00 00 e3 c0 19 f8 65 8b 05 3c 6e cc 76 85 c0 74 0a 5b 5d c3 e8 d0 a1 RSP: 0018:ffffc9000475f728 EFLAGS: 00000206 RAX: 0000000000000002 RBX: 0000000000000200 RCX: 1ffffffff1fac53e RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001 RBP: ffff8880ad844840 R08: 0000000000000001 R09: ffffffff8fd17a07 R10: 0000000000000001 R11: 0000000000000000 R12: ffff888029198060 R13: dffffc0000000000 R14: ffff888029198238 R15: ffffc9000475f828 mptcp_wait_data net/mptcp/protocol.c:1809 [inline] mptcp_recvmsg+0xf8e/0x27b0 net/mptcp/protocol.c:2122 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: 0033:0x7fb1c09b68d9 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:00007fb1bdf2d188 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007fb1c0abaf60 RCX: 00007fb1c09b68d9 RDX: 0000000000000002 RSI: 00000000200017c0 RDI: 0000000000000004 RBP: 00007fb1c0a10cb4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000100 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffe7b6af3ef R14: 00007fb1bdf2d300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: 74 61 je 0x63 2: 00 41 0f add %al,0xf(%rcx) 5: b7 5c mov $0x5c,%bh 7: 24 20 and $0x20,%al 9: 66 81 e3 ff 1f and $0x1fff,%bx e: 0f b7 db movzwl %bx,%ebx 11: be 08 00 00 00 mov $0x8,%esi 16: 48 89 d8 mov %rbx,%rax 19: 48 c1 f8 06 sar $0x6,%rax 1d: 48 8d 3c c5 40 79 d1 lea -0x702e86c0(,%rax,8),%rdi 24: 8f 25: e8 7e 77 61 00 callq 0x6177a8 * 2a: 48 0f a3 1d 26 1f 76 bt %rbx,0xe761f26(%rip) # 0xe761f58 <-- trapping instruction 31: 0e 32: 0f 83 f1 0b 00 00 jae 0xc29 38: 48 8d 1c 5b lea (%rbx,%rbx,2),%rbx 3c: 48 c1 e3 06 shl $0x6,%rbx