rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P16331/1:b..l P6221/1:b..l rcu: (detected by 1, t=10502 jiffies, g=79985, q=27 ncpus=2) task:syz-executor state:R running task stack:21440 pid:6221 tgid:6221 ppid:6193 task_flags:0x400140 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7288 irqentry_exit+0x6f/0x90 kernel/entry/common.c:197 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:rcu_read_unlock include/linux/rcupdate.h:869 [inline] RIP: 0010:is_bpf_text_address+0x200/0x2b0 kernel/bpf/core.c:778 Code: 8b 24 24 8b 05 01 6d 12 0c 44 39 e0 74 0a e8 17 08 f1 ff e9 e1 fe ff ff e8 0d 88 ab 09 89 c5 31 ff 89 c6 e8 42 0c f1 ff 85 ed <74> 10 e8 09 b9 d7 ff 84 c0 74 0e e8 f0 07 f1 ff eb 56 e8 e9 07 f1 RSP: 0018:ffffc90002fe7410 EFLAGS: 00000202 RAX: ffffffff81cea6de RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffff8880332b0000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff81cea506 R10: dffffc0000000000 R11: ffffffff81ac3ae0 R12: 00000000000005d8 R13: dffffc0000000000 R14: 00007fdcb358fed7 R15: 0000000000000000 kernel_text_address+0xa5/0xe0 kernel/extable.c:125 __kernel_text_address+0xd/0x40 kernel/extable.c:79 unwind_get_return_address+0x4d/0x90 arch/x86/kernel/unwind_orc.c:369 arch_stack_walk+0xfc/0x150 arch/x86/kernel/stacktrace.c:26 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:243 [inline] __kasan_slab_free+0x5b/0x80 mm/kasan/common.c:275 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2422 [inline] slab_free mm/slub.c:4695 [inline] kmem_cache_free+0x18f/0x400 mm/slub.c:4797 f2fs_destroy_node_manager+0x322/0xcc0 fs/f2fs/node.c:3381 f2fs_put_super+0xb15/0x1170 fs/f2fs/super.c:1959 generic_shutdown_super+0x135/0x2c0 fs/super.c:643 kill_block_super+0x44/0x90 fs/super.c:1766 kill_f2fs_super+0x390/0x6c0 fs/f2fs/super.c:5353 deactivate_locked_super+0xbc/0x130 fs/super.c:474 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1375 task_work_run+0x1d4/0x260 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop+0xec/0x110 kernel/entry/common.c:43 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fdcb358fed7 RSP: 002b:00007ffd77840748 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007fdcb3611c05 RCX: 00007fdcb358fed7 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffd77840800 RBP: 00007ffd77840800 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffd77841890 R13: 00007fdcb3611c05 R14: 0000000000169d31 R15: 00007ffd778418d0 task:syz.3.2420 state:R running task stack:24152 pid:16331 tgid:16329 ppid:5859 task_flags:0x40044c flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7145 preempt_schedule+0xae/0xc0 kernel/sched/core.c:7169 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:391 [inline] zap_pte_range mm/memory.c:1756 [inline] zap_pmd_range mm/memory.c:1818 [inline] zap_pud_range mm/memory.c:1847 [inline] zap_p4d_range mm/memory.c:1868 [inline] unmap_page_range+0x3a79/0x4370 mm/memory.c:1889 unmap_single_vma mm/memory.c:1932 [inline] unmap_vmas+0x399/0x580 mm/memory.c:1976 exit_mmap+0x248/0xb50 mm/mmap.c:1280 __mmput+0x118/0x430 kernel/fork.c:1129 exit_mm+0x1da/0x2c0 kernel/exit.c:582 do_exit+0x648/0x2300 kernel/exit.c:949 do_group_exit+0x21c/0x2d0 kernel/exit.c:1102 get_signal+0x1286/0x1340 kernel/signal.c:3034 arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337 exit_to_user_mode_loop+0x75/0x110 kernel/entry/common.c:40 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline] do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f7a5318eba9 RSP: 002b:00007f7a53f4d038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: 0000000000010106 RBX: 00007f7a533d6090 RCX: 00007f7a5318eba9 RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000005 RBP: 00007f7a53211e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f7a533d6128 R14: 00007f7a533d6090 R15: 00007ffc92848448 rcu: rcu_preempt kthread timer wakeup didn't happen for 10589 jiffies! g79985 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=119055 rcu: rcu_preempt kthread starved for 10595 jiffies! g79985 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27288 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0x165/0x360 kernel/sched/core.c:7058 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 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: 1297 Comm: aoe_tx0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025 RIP: 0010:find_held_lock kernel/locking/lockdep.c:5348 [inline] RIP: 0010:__lock_release kernel/locking/lockdep.c:5535 [inline] RIP: 0010:lock_release+0x114/0x3e0 kernel/locking/lockdep.c:5889 Code: 24 18 48 89 5c 24 08 44 8d 60 ff 49 8d af f0 0a 00 00 4d 63 ec 48 89 04 24 83 f8 32 0f 83 44 02 00 00 4a 8d 1c ad 00 00 00 00 <4c> 01 eb 48 8d 6c dd 00 48 89 ef 4c 89 f6 e8 89 be dc 09 44 89 64 RSP: 0018:ffffc9000453f618 EFLAGS: 00000087 RAX: 0000000000000003 RBX: 0000000000000008 RCX: 56a2d3355eaf1800 RDX: 0000000000000000 RSI: ffffffff8d9cd00d RDI: ffffffff8be33980 RBP: ffff8880274ac6f0 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff520008a7ec0 R12: 0000000000000002 R13: 0000000000000002 R14: ffffffff99df5f38 R15: ffff8880274abc00 FS: 0000000000000000(0000) GS:ffff888125c15000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f3cb62951f7 CR3: 0000000030c84000 CR4: 0000000000350ef0 Call Trace: __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:149 [inline] _raw_spin_unlock_irqrestore+0x70/0x110 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] uart_port_unlock_irqrestore include/linux/serial_core.h:788 [inline] uart_port_unlock_deref+0x111/0x2f0 drivers/tty/serial/serial_core.c:91 uart_write_room+0xe4/0x170 drivers/tty/serial/serial_core.c:650 handle_tx+0x163/0x610 drivers/net/caif/caif_serial.c:212 __netdev_start_xmit include/linux/netdevice.h:5222 [inline] netdev_start_xmit include/linux/netdevice.h:5231 [inline] xmit_one net/core/dev.c:3839 [inline] dev_hard_start_xmit+0x2d7/0x830 net/core/dev.c:3855 __dev_queue_xmit+0x1b8d/0x3b50 net/core/dev.c:4725 dev_queue_xmit include/linux/netdevice.h:3361 [inline] tx+0x6b/0x190 drivers/block/aoe/aoenet.c:62 kthread+0x1d0/0x3e0 drivers/block/aoe/aoecmd.c:1241 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245