rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 1, t=10502 jiffies, g=68417, q=19 ncpus=2) rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4295051881-4295041379), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10502 jiffies! g68417 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:26528 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5241 [inline] __schedule+0x132c/0x4330 kernel/sched/core.c:6554 schedule+0xbf/0x180 kernel/sched/core.c:6630 schedule_timeout+0x1b9/0x300 kernel/time/timer.c:1935 rcu_gp_fqs_loop+0x2c2/0x1010 kernel/rcu/tree.c:1660 rcu_gp_kthread+0xa3/0x3a0 kernel/rcu/tree.c:1859 kthread+0x26e/0x300 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 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: 3602 Comm: syz-executor.4 Not tainted 6.1.27-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023 RIP: 0010:debug_spin_unlock kernel/locking/spinlock_debug.c:105 [inline] RIP: 0010:do_raw_spin_unlock+0x104/0x8a0 kernel/locking/spinlock_debug.c:140 Code: 41 80 3c 2c 00 74 08 4c 89 ef e8 37 df 74 00 49 c7 45 00 ff ff ff ff 0f b6 04 2b 84 c0 0f 85 c9 03 00 00 41 c7 06 ff ff ff ff <48> c7 c0 60 8a d9 8c 48 c1 e8 03 80 3c 28 00 74 0c 48 c7 c7 60 8a RSP: 0018:ffffc90000007ba0 EFLAGS: 00000046 RAX: 0000000000000000 RBX: 1ffffffff23accde RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffffff91d666e8 RBP: dffffc0000000000 R08: dffffc0000000000 R09: fffffbfff23accde R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffffffff23accdf R13: ffffffff91d666f8 R14: ffffffff91d666f0 R15: ffffffff91d666e8 FS: 0000555556801400(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020001700 CR3: 00000000391ad000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:150 [inline] _raw_spin_unlock_irqrestore+0x7d/0x130 kernel/locking/spinlock.c:194 debug_object_activate+0x274/0x690 lib/debugobjects.c:693 debug_hrtimer_activate kernel/time/hrtimer.c:420 [inline] debug_activate kernel/time/hrtimer.c:475 [inline] enqueue_hrtimer+0x30/0x390 kernel/time/hrtimer.c:1084 __run_hrtimer kernel/time/hrtimer.c:1702 [inline] __hrtimer_run_queues+0x728/0xe50 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x392/0x980 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1096 [inline] __sysvec_apic_timer_interrupt+0x156/0x580 arch/x86/kernel/apic/apic.c:1113 sysvec_apic_timer_interrupt+0x8c/0xb0 arch/x86/kernel/apic/apic.c:1107 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:649 RIP: 0010:lock_acquire+0x26f/0x5a0 kernel/locking/lockdep.c:5673 Code: 2b 00 74 08 4c 89 f7 e8 0f 40 76 00 f6 44 24 61 02 0f 85 84 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25 RSP: 0018:ffffc900056ef2e0 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 1ffff92000adde68 RCX: 1ffff92000adde08 RDX: dffffc0000000000 RSI: ffffffff8aebe1a0 RDI: ffffffff8b3cbfa0 RBP: ffffc900056ef438 R08: dffffc0000000000 R09: fffffbfff2050445 R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff92000adde64 R13: dffffc0000000000 R14: ffffc900056ef340 R15: 0000000000000246 rcu_lock_acquire+0x2a/0x30 include/linux/rcupdate.h:306 rcu_read_lock include/linux/rcupdate.h:747 [inline] page_ext_get+0x18/0x270 mm/page_ext.c:157 page_table_check_set+0x1fa/0x550 mm/page_table_check.c:107 page_table_check_pte_set include/linux/page_table_check.h:83 [inline] set_pte_at arch/x86/include/asm/pgtable.h:1009 [inline] copy_present_pte mm/memory.c:990 [inline] copy_pte_range mm/memory.c:1081 [inline] copy_pmd_range mm/memory.c:1167 [inline] copy_pud_range mm/memory.c:1204 [inline] copy_p4d_range mm/memory.c:1228 [inline] copy_page_range+0x2ca2/0x4580 mm/memory.c:1326 dup_mmap kernel/fork.c:695 [inline] dup_mm+0xddf/0x1610 kernel/fork.c:1532 copy_mm+0xca/0x160 kernel/fork.c:1581 copy_process+0x19a2/0x4020 kernel/fork.c:2259 kernel_clone+0x222/0x920 kernel/fork.c:2679 __do_sys_clone kernel/fork.c:2820 [inline] __se_sys_clone kernel/fork.c:2804 [inline] __x64_sys_clone+0x231/0x280 kernel/fork.c:2804 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f6ecbc89e9b Code: ed 0f 85 60 01 00 00 64 4c 8b 0c 25 10 00 00 00 45 31 c0 4d 8d 91 d0 02 00 00 31 d2 31 f6 bf 11 00 20 01 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 0f 87 89 00 00 00 41 89 c5 85 c0 0f 85 90 00 00 RSP: 002b:00007ffe6d14bc60 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f6ecbc89e9b RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000555556801400 R10: 00005555568016d0 R11: 0000000000000246 R12: 0000000000000001 R13: 0000000000000000 R14: 0000000000000001 R15: 00007ffe6d14bd40