rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): (detected by 1, t=10502 jiffies, g=291653, q=1701) rcu: All QSes seen, last rcu_preempt kthread activity 3611 (4295132121-4295128510), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread timer wakeup didn't happen for 3610 jiffies! g291653 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=111736 rcu: rcu_preempt kthread starved for 3611 jiffies! g291653 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:26352 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4339 [inline] __schedule+0xb98/0x1120 kernel/sched/core.c:5147 schedule+0x14b/0x200 kernel/sched/core.c:5226 schedule_timeout+0x1aa/0x2c0 kernel/time/timer.c:1892 rcu_gp_fqs_loop kernel/rcu/tree.c:2004 [inline] rcu_gp_kthread+0x112d/0x2190 kernel/rcu/tree.c:2177 kthread+0x39a/0x3c0 kernel/kthread.c:313 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294 rcu: Stack dump where RCU GP kthread last ran: NMI backtrace for cpu 1 CPU: 1 PID: 19883 Comm: syz-executor.1 Not tainted 5.13.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x202/0x31e lib/dump_stack.c:120 nmi_cpu_backtrace+0x16c/0x190 lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0x191/0x2f0 lib/nmi_backtrace.c:62 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline] rcu_check_gp_kthread_starvation+0x20d/0x250 kernel/rcu/tree_stall.h:478 print_other_cpu_stall kernel/rcu/tree_stall.h:583 [inline] check_cpu_stall kernel/rcu/tree_stall.h:708 [inline] rcu_pending kernel/rcu/tree.c:3911 [inline] rcu_sched_clock_irq+0x2297/0x2a30 kernel/rcu/tree.c:2649 update_process_times+0x197/0x200 kernel/time/timer.c:1796 tick_sched_handle kernel/time/tick-sched.c:226 [inline] tick_sched_timer+0x27d/0x420 kernel/time/tick-sched.c:1373 __run_hrtimer kernel/time/hrtimer.c:1537 [inline] __hrtimer_run_queues+0x4cb/0xa60 kernel/time/hrtimer.c:1601 hrtimer_interrupt+0x3b3/0x1040 kernel/time/hrtimer.c:1663 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1089 [inline] __sysvec_apic_timer_interrupt+0xf9/0x270 arch/x86/kernel/apic/apic.c:1106 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1100 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:647 RIP: 0010:lock_acquire+0x1f6/0x720 kernel/locking/lockdep.c:5516 Code: f6 84 24 a1 00 00 00 02 0f 85 8d 02 00 00 f7 c3 00 02 00 00 49 bd 00 00 00 00 00 fc ff df 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 4b c7 44 3d 09 00 00 00 00 43 c7 44 3d RSP: 0018:ffffc9001e71f040 EFLAGS: 00000206 RAX: 1ffff92003ce3e1c RBX: 0000000000000246 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9001e71f1c0 R08: dffffc0000000000 R09: fffffbfff204d9b1 R10: fffffbfff204d9b1 R11: 0000000000000000 R12: 0000000000000000 R13: dffffc0000000000 R14: 0000000000000000 R15: 1ffff92003ce3e10 rcu_lock_acquire+0x20/0x30 include/linux/rcupdate.h:267 rcu_read_lock include/linux/rcupdate.h:657 [inline] lock_page_memcg+0xbc/0x460 mm/memcontrol.c:1982 page_remove_rmap+0x2b/0x1080 mm/rmap.c:1348 zap_pte_range+0x92a/0x1b60 mm/memory.c:1270 zap_pmd_range mm/memory.c:1374 [inline] zap_pud_range mm/memory.c:1403 [inline] zap_p4d_range mm/memory.c:1424 [inline] unmap_page_range+0x55a/0x890 mm/memory.c:1445 unmap_vmas+0x1d1/0x360 mm/memory.c:1522 exit_mmap+0x2af/0x5f0 mm/mmap.c:3208 __mmput+0x111/0x370 kernel/fork.c:1096 exit_mm+0x67e/0x7d0 kernel/exit.c:502 do_exit+0x6b9/0x23d0 kernel/exit.c:813 do_group_exit+0x168/0x2d0 kernel/exit.c:923 get_signal+0x1770/0x2180 kernel/signal.c:2835 arch_do_signal_or_restart+0x8e/0x6c0 arch/x86/kernel/signal.c:789 handle_signal_work kernel/entry/common.c:147 [inline] exit_to_user_mode_loop kernel/entry/common.c:171 [inline] exit_to_user_mode_prepare+0xac/0x200 kernel/entry/common.c:208 __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline] syscall_exit_to_user_mode+0x26/0x70 kernel/entry/common.c:301 do_syscall_64+0x4b/0xb0 arch/x86/entry/common.c:57 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x4665d9 Code: Unable to access opcode bytes at RIP 0x4665af. RSP: 002b:00007f85a7d31218 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 000000000056bf88 RCX: 00000000004665d9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000056bf88 RBP: 000000000056bf80 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf8c R13: 00007ffc7da16aff R14: 00007f85a7d31300 R15: 0000000000022000