rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 0, t=10502 jiffies, g=24457, q=13) rcu: All QSes seen, last rcu_preempt kthread activity 10497 (4294967317-4294956820), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10497 jiffies! g24457 f0x2 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: NMI backtrace for cpu 0 CPU: 0 PID: 10528 Comm: syz-executor.1 Not tainted 5.15.0-rc2-next-20210920-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_check_gp_kthread_starvation.cold+0x1fb/0x200 kernel/rcu/tree_stall.h:481 print_other_cpu_stall kernel/rcu/tree_stall.h:586 [inline] check_cpu_stall kernel/rcu/tree_stall.h:729 [inline] rcu_pending kernel/rcu/tree.c:3878 [inline] rcu_sched_clock_irq+0x2125/0x2200 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:get_current arch/x86/include/asm/current.h:15 [inline] RIP: 0010:___might_sleep+0x172/0x2c0 kernel/sched/core.c:9479 Code: 48 83 e8 64 48 39 d0 0f 89 bb fa a0 07 48 85 d2 0f 84 b2 fa a0 07 5b 5d 41 5c 41 5d 41 5e c3 9c 58 f6 c4 02 0f 84 2c ff ff ff <65> 4c 8b 2c 25 40 f0 01 00 49 8d 7d 2c 48 b8 00 00 00 00 00 fc ff RSP: 0018:ffffc9000b74f6d0 EFLAGS: 00000202 RAX: 0000000000000246 RBX: 0000000000000000 RCX: 0000000000000001 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8880754bdb3c RBP: ffffffff8a8b0100 R08: 0000000000000000 R09: ffffffff8fd069cf R10: fffffbfff1fa0d39 R11: 0000000000000000 R12: 0000000000000c9f R13: 0000000000000000 R14: ffff8880754bd700 R15: ffff88807dde8bc0 lock_sock_fast+0x49/0x100 net/core/sock.c:3231 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: 0033:0x7fd6ba795739 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:00007fd6b7d0c188 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007fd6ba899f80 RCX: 00007fd6ba795739 RDX: 0000000000000002 RSI: 00000000200017c0 RDI: 0000000000000005 RBP: 00007fd6ba7efcc4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000100 R11: 0000000000000246 R12: 00007fd6ba899f80 R13: 00007ffd965ccb7f R14: 00007fd6b7d0c300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: 48 83 e8 64 sub $0x64,%rax 4: 48 39 d0 cmp %rdx,%rax 7: 0f 89 bb fa a0 07 jns 0x7a0fac8 d: 48 85 d2 test %rdx,%rdx 10: 0f 84 b2 fa a0 07 je 0x7a0fac8 16: 5b pop %rbx 17: 5d pop %rbp 18: 41 5c pop %r12 1a: 41 5d pop %r13 1c: 41 5e pop %r14 1e: c3 retq 1f: 9c pushfq 20: 58 pop %rax 21: f6 c4 02 test $0x2,%ah 24: 0f 84 2c ff ff ff je 0xffffff56 * 2a: 65 4c 8b 2c 25 40 f0 mov %gs:0x1f040,%r13 <-- trapping instruction 31: 01 00 33: 49 8d 7d 2c lea 0x2c(%r13),%rdi 37: 48 rex.W 38: b8 00 00 00 00 mov $0x0,%eax 3d: 00 fc add %bh,%ah 3f: ff .byte 0xff