rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: (detected by 1, t=10502 jiffies, g=52605, q=216 ncpus=2) rcu: All QSes seen, last rcu_preempt kthread activity 10502 (4295054457-4295043955), jiffies_till_next_fqs=1, root ->qsmask 0x0 rcu: rcu_preempt kthread starved for 10502 jiffies! g52605 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:25168 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5378 [inline] __schedule+0x18bc/0x4c40 kernel/sched/core.c:6765 __schedule_loop kernel/sched/core.c:6842 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6857 schedule_timeout+0x15a/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2024 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2226 kthread+0x7a9/0x920 kernel/kthread.c:464 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 9508 Comm: syz-executor Not tainted 6.14.0-rc5-syzkaller-00234-gb7c90e3e717a #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:lockdep_recursion_finish kernel/locking/lockdep.c:469 [inline] RIP: 0010:lock_release+0x5f9/0xa30 kernel/locking/lockdep.c:5874 Code: 10 48 8b 5c 24 28 49 89 dd 4c 8d b4 24 90 00 00 00 48 c7 c7 00 c5 2a 8c e8 44 0d 64 0a b8 ff ff ff ff 65 0f c1 05 27 8b 65 7e <83> f8 01 0f 85 9a 00 00 00 4c 89 f3 48 c1 eb 03 42 80 3c 3b 00 74 RSP: 0018:ffffc90000007a40 EFLAGS: 00000057 RAX: 0000000000000001 RBX: 0000000000000046 RCX: ffffc90000007a03 RDX: 0000000000000009 RSI: ffffffff8c2ac500 RDI: ffffffff8c802ae0 RBP: ffffc90000007b70 R08: ffffffff903bcd77 R09: 1ffffffff20779ae R10: dffffc0000000000 R11: fffffbfff20779af R12: 1ffff92000000f54 R13: 0000000000000046 R14: ffffc90000007ad0 R15: dffffc0000000000 FS: 0000555563ebd500(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c3d4e62 CR3: 00000000679be000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:149 [inline] _raw_spin_unlock_irqrestore+0x79/0x140 kernel/locking/spinlock.c:194 debug_object_deactivate+0x2d5/0x390 lib/debugobjects.c:888 debug_hrtimer_deactivate kernel/time/hrtimer.c:460 [inline] debug_deactivate+0x1b/0x220 kernel/time/hrtimer.c:502 __run_hrtimer kernel/time/hrtimer.c:1769 [inline] __hrtimer_run_queues+0x305/0xd30 kernel/time/hrtimer.c:1865 hrtimer_interrupt+0x403/0xa40 kernel/time/hrtimer.c:1927 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x110/0x420 arch/x86/kernel/apic/apic.c:1055 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:check_preemption_disabled+0x2/0x120 lib/smp_processor_id.c:13 Code: 2a 80 8c 48 c7 c6 c0 2a 80 8c eb 1c 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 41 57 <41> 56 41 54 53 48 83 ec 10 65 48 8b 04 25 28 00 00 00 48 89 44 24 RSP: 0018:ffffc90002eb7010 EFLAGS: 00000287 RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff819cfa10 RDX: 0000000000000000 RSI: ffffffff8c802ac0 RDI: ffffffff8c802a80 RBP: ffffc90002eb7180 R08: ffffffff903bcd77 R09: 1ffffffff20779ae R10: dffffc0000000000 R11: fffffbfff20779af R12: 1ffff920005d6e14 R13: ffffffff82325f77 R14: 1ffff920005d6e38 R15: dffffc0000000000 rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline] rcu_is_watching+0x15/0xb0 kernel/rcu/tree.c:716 trace_lock_release include/trace/events/lock.h:69 [inline] lock_release+0xbf/0xa30 kernel/locking/lockdep.c:5862 rcu_lock_release include/linux/rcupdate.h:347 [inline] rcu_read_unlock include/linux/rcupdate.h:880 [inline] page_ext_put+0xa3/0xc0 mm/page_ext.c:550 __page_table_check_ptes_set+0x30f/0x410 mm/page_table_check.c:225 page_table_check_ptes_set include/linux/page_table_check.h:74 [inline] set_ptes include/linux/pgtable.h:288 [inline] __copy_present_ptes mm/memory.c:968 [inline] copy_present_ptes mm/memory.c:1051 [inline] copy_pte_range mm/memory.c:1174 [inline] copy_pmd_range+0x4523/0x77b0 mm/memory.c:1262 copy_pud_range mm/memory.c:1299 [inline] copy_p4d_range mm/memory.c:1323 [inline] copy_page_range+0x99f/0xe90 mm/memory.c:1421 dup_mmap kernel/fork.c:748 [inline] dup_mm kernel/fork.c:1700 [inline] copy_mm+0x1269/0x2160 kernel/fork.c:1752 copy_process+0x17d1/0x3cf0 kernel/fork.c:2403 kernel_clone+0x223/0x870 kernel/fork.c:2815 __do_sys_clone kernel/fork.c:2958 [inline] __se_sys_clone kernel/fork.c:2942 [inline] __x64_sys_clone+0x267/0x2e0 kernel/fork.c:2942 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fdbaad839d3 Code: 1f 84 00 00 00 00 00 64 48 8b 04 25 10 00 00 00 45 31 c0 31 d2 31 f6 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 89 c2 85 c0 75 2c 64 48 8b 04 25 10 00 00 RSP: 002b:00007ffd7216eb08 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fdbaad839d3 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 0000555563ebd7d0 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000927c0 R14: 0000000000104e1f R15: 00007ffd7216eca0