rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P1081/1:b..l (detected by 0, t=10502 jiffies, g=290977, q=32) task:kworker/u4:6 state:R running task stack:24200 pid: 1081 ppid: 2 flags:0x00004000 Workqueue: bat_events batadv_nc_worker Call Trace: context_switch kernel/sched/core.c:4972 [inline] __schedule+0xa9a/0x4940 kernel/sched/core.c:6253 preempt_schedule_irq+0x4e/0x90 kernel/sched/core.c:6668 irqentry_exit+0x31/0x80 kernel/entry/common.c:425 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:lock_acquire+0x1ef/0x510 kernel/locking/lockdep.c:5605 Code: 7e 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:ffffc90004527ba0 EFLAGS: 00000206 RAX: dffffc0000000000 RBX: 1ffff920008a4f76 RCX: 77f747f643e68efe RDX: 1ffff1100397096b RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8ff76a07 R10: fffffbfff1feed40 R11: 0000000000000000 R12: 0000000000000002 R13: 0000000000000000 R14: ffffffff8bb811a0 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:268 [inline] rcu_read_lock include/linux/rcupdate.h:688 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:412 [inline] batadv_nc_worker+0x12d/0xfa0 net/batman-adv/network-coding.c:723 process_one_work+0x9b2/0x1690 kernel/workqueue.c:2298 worker_thread+0x658/0x11f0 kernel/workqueue.c:2445 kthread+0x405/0x4f0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: rcu_preempt kthread starved for 10500 jiffies! g290977 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:28896 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4972 [inline] __schedule+0xa9a/0x4940 kernel/sched/core.c:6253 schedule+0xd2/0x260 kernel/sched/core.c:6326 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: 25801 Comm: syz-executor.1 Not tainted 5.16.0-rc4-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:111 nmi_trigger_cpumask_backtrace+0x1b3/0x230 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:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline] RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202 Code: 0f 1f 44 00 00 55 48 8b 74 24 08 48 89 fd 48 83 c7 18 e8 4e df 14 f8 48 89 ef e8 96 55 15 f8 e8 a1 15 36 f8 fb bf 01 00 00 00 36 1e 08 f8 65 8b 05 3f 5c bb 76 85 c0 74 02 5d c3 e8 5b 31 b9 RSP: 0018:ffffc90009f477b8 EFLAGS: 00000202 RAX: 00000000023e9845 RBX: dffffc0000000000 RCX: 1ffffffff1ff1426 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001 RBP: ffff8880695506b0 R08: 0000000000000001 R09: ffffffff8ff76a37 R10: 0000000000000001 R11: 000000000008808a R12: 1ffffffff1701e30 R13: ffff888019f68080 R14: ffff8880695506b0 R15: ffffc90009f47888 rwsem_down_write_slowpath+0x576/0x1110 kernel/locking/rwsem.c:1127 __down_write_common kernel/locking/rwsem.c:1268 [inline] __down_write_common kernel/locking/rwsem.c:1265 [inline] __down_write kernel/locking/rwsem.c:1277 [inline] down_write+0x135/0x150 kernel/locking/rwsem.c:1524 i_mmap_lock_write include/linux/fs.h:498 [inline] unlink_file_vma+0x7d/0x110 mm/mmap.c:169 free_pgtables+0x1b3/0x2f0 mm/memory.c:427 exit_mmap+0x1df/0x630 mm/mmap.c:3171 __mmput+0x122/0x4b0 kernel/fork.c:1113 mmput+0x56/0x60 kernel/fork.c:1134 exit_mm kernel/exit.c:507 [inline] do_exit+0xb27/0x2b40 kernel/exit.c:819 do_group_exit+0x125/0x310 kernel/exit.c:929 get_signal+0x47d/0x2220 kernel/signal.c:2852 arch_do_signal_or_restart+0x2a9/0x1c40 arch/x86/kernel/signal.c:868 handle_signal_work kernel/entry/common.c:148 [inline] exit_to_user_mode_loop kernel/entry/common.c:172 [inline] exit_to_user_mode_prepare+0x17d/0x290 kernel/entry/common.c:207 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:300 do_syscall_64+0x42/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f8ad1aa9af9 Code: Unable to access opcode bytes at RIP 0x7f8ad1aa9acf. RSP: 002b:00007f8ad09fe218 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007f8ad1bbd030 RCX: 00007f8ad1aa9af9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f8ad1bbd030 RBP: 00007f8ad1bbd028 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f8ad1bbd034 R13: 00007fff643313af R14: 00007f8ad09fe300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: 7e a6 jle 0xffffffa8 2: 7e 83 jle 0xffffff87 4: f8 clc 5: 01 0f add %ecx,(%rdi) 7: 85 b4 02 00 00 9c 58 test %esi,0x589c0000(%rdx,%rax,1) e: f6 c4 02 test $0x2,%ah 11: 0f 85 9f 02 00 00 jne 0x2b6 17: 48 83 7c 24 08 00 cmpq $0x0,0x8(%rsp) 1d: 74 01 je 0x20 1f: fb sti 20: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 27: fc ff df * 2a: 48 01 c3 add %rax,%rbx <-- trapping instruction 2d: 48 c7 03 00 00 00 00 movq $0x0,(%rbx) 34: 48 c7 43 08 00 00 00 movq $0x0,0x8(%rbx) 3b: 00 3c: 48 rex.W 3d: 8b .byte 0x8b 3e: 84 .byte 0x84 3f: 24 .byte 0x24