rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (1 GPs behind) idle=809/1/0x4000000000000000 softirq=15136/15137 fqs=14 (t=10501 jiffies g=21625 q=163) rcu: rcu_preempt kthread starved for 10470 jiffies! g21625 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: 9731 Comm: syz-executor.2 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:trace_lock_release include/trace/events/lock.h:58 [inline] RIP: 0010:lock_release+0x516/0x720 kernel/locking/lockdep.c:5636 Code: 14 11 38 d0 7c 08 84 d2 0f 85 da 01 00 00 44 8b 05 07 16 13 0c 45 85 c0 0f 85 a5 fe ff ff e9 93 82 94 07 65 ff 05 2a 71 a6 7e <48> 8b 05 23 ba fe 0b e8 7e d1 05 00 85 c0 74 17 65 ff 0d 13 71 a6 RSP: 0018:ffffc90004c37660 EFLAGS: 00000203 RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff815b7a61 RDX: fffffbfff1adcc1b RSI: 0000000000000008 RDI: ffffffff8d6e60d0 RBP: 1ffff92000986ece R08: 0000000000000000 R09: ffffffff8d6e60d7 R10: fffffbfff1adcc1a R11: 0000000000000000 R12: ffff88807c7b0c60 R13: ffffc90004c37828 R14: dffffc0000000000 R15: ffff88807c7b0bc0 FS: 00007f4b0bca6700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2da2a000 CR3: 000000001ec0f000 CR4: 00000000001506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:174 [inline] _raw_spin_unlock_bh+0x12/0x30 kernel/locking/spinlock.c:210 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] sock_recvmsg net/socket.c:962 [inline] sock_recvmsg net/socket.c:958 [inline] ____sys_recvmsg+0x2c4/0x600 net/socket.c:2628 ___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: 0033:0x7f4b0e72f739 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:00007f4b0bca6188 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f4b0e833f80 RCX: 00007f4b0e72f739 RDX: 0000000000000001 RSI: 0000000020001280 RDI: 0000000000000003 RBP: 00007f4b0e789cc4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000100 R11: 0000000000000246 R12: 00007f4b0e833f80 R13: 00007ffca63597af R14: 00007f4b0bca6300 R15: 0000000000022000 NMI backtrace for cpu 1 CPU: 1 PID: 9714 Comm: syz-executor.1 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: <IRQ> __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 </IRQ> 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:ffffc90004b0f600 EFLAGS: 00000206 RAX: dffffc0000000000 RBX: 1ffff92000961ec2 RCX: ffffffff815b2f8f RDX: 1ffff11003ac688c RSI: 0000000000000201 RDI: 0000000000000000 RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff8fd029cf R10: fffffbfff1fa0539 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: ffff888025ac7120 R15: 0000000000000000 __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_fast+0x5d/0x100 net/core/sock.c:3232 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] sock_recvmsg net/socket.c:962 [inline] sock_recvmsg net/socket.c:958 [inline] ____sys_recvmsg+0x2c4/0x600 net/socket.c:2628 ___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: 0033:0x7fb6ecd0e739 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:00007fb6ea285188 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007fb6ece12f80 RCX: 00007fb6ecd0e739 RDX: 0000000000000001 RSI: 0000000020001280 RDI: 0000000000000003 RBP: 00007fb6ecd68cc4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000100 R11: 0000000000000246 R12: 00007fb6ece12f80 R13: 00007fff765e9c0f R14: 00007fb6ea285300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: 14 11 adc $0x11,%al 2: 38 d0 cmp %dl,%al 4: 7c 08 jl 0xe 6: 84 d2 test %dl,%dl 8: 0f 85 da 01 00 00 jne 0x1e8 e: 44 8b 05 07 16 13 0c mov 0xc131607(%rip),%r8d # 0xc13161c 15: 45 85 c0 test %r8d,%r8d 18: 0f 85 a5 fe ff ff jne 0xfffffec3 1e: e9 93 82 94 07 jmpq 0x79482b6 23: 65 ff 05 2a 71 a6 7e incl %gs:0x7ea6712a(%rip) # 0x7ea67154 * 2a: 48 8b 05 23 ba fe 0b mov 0xbfeba23(%rip),%rax # 0xbfeba54 <-- trapping instruction 31: e8 7e d1 05 00 callq 0x5d1b4 36: 85 c0 test %eax,%eax 38: 74 17 je 0x51 3a: 65 gs 3b: ff .byte 0xff 3c: 0d .byte 0xd 3d: 13 71 a6 adc -0x5a(%rcx),%esi