rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P969/1:b..l P5830/1:b..l rcu: (detected by 0, t=10502 jiffies, g=31665, q=215 ncpus=2) task:syz-executor state:R running task stack:23136 pid:5830 tgid:5830 ppid:5815 task_flags:0x400140 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5378 [inline] __schedule+0xf43/0x5890 kernel/sched/core.c:6765 preempt_schedule_common+0x44/0xc0 kernel/sched/core.c:6944 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3e/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] copy_pte_range mm/memory.c:1201 [inline] copy_pmd_range mm/memory.c:1262 [inline] copy_pud_range mm/memory.c:1299 [inline] copy_p4d_range mm/memory.c:1323 [inline] copy_page_range+0x1e7f/0x5690 mm/memory.c:1421 dup_mmap kernel/fork.c:748 [inline] dup_mm kernel/fork.c:1700 [inline] copy_mm kernel/fork.c:1752 [inline] copy_process+0x7ccb/0x8c50 kernel/fork.c:2403 kernel_clone+0xfd/0x960 kernel/fork.c:2815 __do_sys_clone+0xcf/0x120 kernel/fork.c:2958 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f80263839d3 RSP: 002b:00007ffef7d20a38 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f80263839d3 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001 R10: 0000555581bd47d0 R11: 0000000000000246 R12: 0000000000000000 R13: 00000000000927c0 R14: 000000000004d536 R15: 00007ffef7d20bd0 task:kworker/0:2 state:R running task stack:21120 pid:969 tgid:969 ppid:2 task_flags:0x4208060 flags:0x00004000 Workqueue: events_power_efficient gc_worker Call Trace: context_switch kernel/sched/core.c:5378 [inline] __schedule+0xf43/0x5890 kernel/sched/core.c:6765 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7087 irqentry_exit+0x36/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire.part.0+0x155/0x380 kernel/locking/lockdep.c:5816 Code: b8 ff ff ff ff 65 0f c1 05 e0 da 6b 7e 83 f8 01 0f 85 d0 01 00 00 9c 58 f6 c4 02 0f 85 e5 01 00 00 48 85 ed 0f 85 b6 01 00 00 <48> b8 00 00 00 00 00 fc ff df 48 01 c3 48 c7 03 00 00 00 00 48 c7 RSP: 0018:ffffc90003b77a70 EFLAGS: 00000206 RAX: 0000000000000046 RBX: 1ffff9200076ef4f RCX: 0000000066f07bde RDX: 0000000000000001 RSI: ffffffff8b6cef80 RDI: ffffffff8bd35640 RBP: 0000000000000200 R08: 0000000000000000 R09: fffffbfff2dd8598 R10: ffffffff96ec2cc7 R11: 0000000000000002 R12: 0000000000000000 R13: ffffffff8e1bcc80 R14: 0000000000000000 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:337 [inline] rcu_read_lock include/linux/rcupdate.h:849 [inline] gc_worker+0x242/0x16a0 net/netfilter/nf_conntrack_core.c:1532 process_one_work+0x9c5/0x1ba0 kernel/workqueue.c:3236 process_scheduled_works kernel/workqueue.c:3317 [inline] worker_thread+0x6c8/0xf00 kernel/workqueue.c:3398 kthread+0x3af/0x750 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 rcu: rcu_preempt kthread timer wakeup didn't happen for 10547 jiffies! g31665 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=1 timer-softirq=20079 rcu: rcu_preempt kthread starved for 10553 jiffies! g31665 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:27552 pid:17 tgid:17 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5378 [inline] __schedule+0xf43/0x5890 kernel/sched/core.c:6765 __schedule_loop kernel/sched/core.c:6842 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6857 schedule_timeout+0x124/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1eb/0xb00 kernel/rcu/tree.c:2024 rcu_gp_kthread+0x271/0x380 kernel/rcu/tree.c:2226 kthread+0x3af/0x750 kernel/kthread.c:464 ret_from_fork+0x45/0x80 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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 1289 Comm: aoe_tx0 Not tainted 6.14.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:__lock_acquire+0xc8c/0x3c40 kernel/locking/lockdep.c:5223 Code: 8d 3c c3 e8 56 c9 c0 09 85 c0 74 c7 4c 8b 6c 24 78 48 c7 c2 30 89 62 90 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 0f b6 14 02 <48> c7 c0 30 89 62 90 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 b0 RSP: 0018:ffffc9000476f748 EFLAGS: 00000802 RAX: dffffc0000000000 RBX: ced034ad5846f22c RCX: ffffffff81966e42 RDX: 0000000000000000 RSI: 0000000000000008 RDI: 00000000ed034adc RBP: 0000000000000000 R08: 0000000000000000 R09: fffffbfff2dd8599 R10: ffffffff96ec2ccf R11: 0000000000000002 R12: ffffed100502b15d R13: ffff888028158000 R14: 0000000000000003 R15: ffff888028158b40 FS: 0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000400000404030 CR3: 0000000063f56000 CR4: 00000000003526f0 Call Trace: lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5851 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162 uart_port_lock_irqsave include/linux/serial_core.h:715 [inline] uart_write+0x13b/0xb30 drivers/tty/serial/serial_core.c:626 handle_tx+0x203/0x630 drivers/net/caif/caif_serial.c:236 __netdev_start_xmit include/linux/netdevice.h:5151 [inline] netdev_start_xmit include/linux/netdevice.h:5160 [inline] xmit_one net/core/dev.c:3806 [inline] dev_hard_start_xmit+0x9a/0x7b0 net/core/dev.c:3822 __dev_queue_xmit+0x7f0/0x43e0 net/core/dev.c:4655 dev_queue_xmit include/linux/netdevice.h:3313 [inline] tx+0xcc/0x190 drivers/block/aoe/aoenet.c:62 kthread+0x1e7/0x3c0 drivers/block/aoe/aoecmd.c:1237 kthread+0x3af/0x750 kernel/kthread.c:464 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244