rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P9489/1:b..l (detected by 1, t=10502 jiffies, g=15625, q=43) task:syz-executor.5 state:R running task stack:27776 pid: 9489 ppid: 6577 flags:0x00000000 Call Trace: context_switch kernel/sched/core.c:4940 [inline] __schedule+0x940/0x26f0 kernel/sched/core.c:6287 preempt_schedule_common+0x45/0xc0 kernel/sched/core.c:6459 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:35 __raw_spin_unlock include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock+0x36/0x40 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:403 [inline] filemap_map_pages+0x1216/0x1880 mm/filemap.c:3338 do_fault_around mm/memory.c:4151 [inline] do_read_fault mm/memory.c:4166 [inline] do_fault mm/memory.c:4300 [inline] handle_pte_fault mm/memory.c:4558 [inline] __handle_mm_fault+0x28dd/0x5320 mm/memory.c:4693 handle_mm_fault+0x1c8/0x790 mm/memory.c:4791 faultin_page mm/gup.c:937 [inline] __get_user_pages+0x503/0xf80 mm/gup.c:1158 populate_vma_page_range+0x24d/0x330 mm/gup.c:1490 __mm_populate+0x1ea/0x3e0 mm/gup.c:1599 mm_populate include/linux/mm.h:2624 [inline] vm_mmap_pgoff+0x20e/0x290 mm/util.c:524 ksys_mmap_pgoff+0xe1/0x620 mm/mmap.c:1624 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: 0033:0x7f4ac7fc3739 RSP: 002b:00007f4ac5519188 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007f4ac80c8038 RCX: 00007f4ac7fc3739 RDX: b635773f06ebbeee RSI: 0000000000b36000 RDI: 0000000020000000 RBP: 00007f4ac801dcc4 R08: ffffffffffffffff R09: 0000000000000000 R10: 0000000000008031 R11: 0000000000000246 R12: 00007f4ac80c8038 R13: 00007fffa50ef54f R14: 00007f4ac5519300 R15: 0000000000022000 rcu: rcu_preempt kthread starved for 10498 jiffies! g15625 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:4940 [inline] __schedule+0x940/0x26f0 kernel/sched/core.c:6287 schedule+0xd3/0x270 kernel/sched/core.c:6366 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x186/0x800 kernel/rcu/tree.c:1957 rcu_gp_kthread+0x1de/0x320 kernel/rcu/tree.c:2130 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: 9490 Comm: syz-executor.3 Not tainted 5.15.0-rc1-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:3880 [inline] rcu_sched_clock_irq+0x2125/0x2200 kernel/rcu/tree.c:2599 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: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 3a ec 23 f8 48 89 ef e8 82 62 24 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 33 23 18 f8 65 8b 05 2c 7d ca 76 85 c0 74 0a 5b 5d c3 e8 90 c2 RSP: 0018:ffffc90002f9f700 EFLAGS: 00000206 RAX: 0000000000000006 RBX: 0000000000000200 RCX: 1ffffffff1fa8a7a RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001 RBP: ffff88806d7bb040 R08: 0000000000000001 R09: ffffffff8fcfa9e7 R10: 0000000000000001 R11: 0000000000000000 R12: ffff88801df60060 R13: ffffc90002f9f808 R14: dffffc0000000000 R15: ffff88801df60000 mptcp_wait_data net/mptcp/protocol.c:1767 [inline] mptcp_recvmsg+0xf47/0x2780 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+0x25e/0x6e0 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: 0033:0x7faa4a8f7739 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:00007faa47e6e188 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007faa4a9fbf80 RCX: 00007faa4a8f7739 RDX: 0000000000000008 RSI: 00000000200017c0 RDI: 0000000000000004 RBP: 00007faa4a951cc4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000100 R11: 0000000000000246 R12: 00007faa4a9fbf80 R13: 00007ffd670cb21f R14: 00007faa47e6e300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: 74 24 je 0x26 2: 10 e8 adc %ch,%al 4: 3a ec cmp %ah,%ch 6: 23 f8 and %eax,%edi 8: 48 89 ef mov %rbp,%rdi b: e8 82 62 24 f8 callq 0xf8246292 10: 81 e3 00 02 00 00 and $0x200,%ebx 16: 75 25 jne 0x3d 18: 9c pushfq 19: 58 pop %rax 1a: f6 c4 02 test $0x2,%ah 1d: 75 2d jne 0x4c 1f: 48 85 db test %rbx,%rbx 22: 74 01 je 0x25 24: fb sti 25: bf 01 00 00 00 mov $0x1,%edi * 2a: e8 33 23 18 f8 callq 0xf8182362 <-- trapping instruction 2f: 65 8b 05 2c 7d ca 76 mov %gs:0x76ca7d2c(%rip),%eax # 0x76ca7d62 36: 85 c0 test %eax,%eax 38: 74 0a je 0x44 3a: 5b pop %rbx 3b: 5d pop %rbp 3c: c3 retq 3d: e8 .byte 0xe8 3e: 90 nop 3f: c2 .byte 0xc2