rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P140/2:b..l P9935/1:b..l P9958/2:b..l P3496/1:b..l P9959/3:b..l rcu: (detected by 0, t=10502 jiffies, g=41329, q=207 ncpus=2) task:syz.5.1109 state:R running task stack:24984 pid:9959 tgid:9959 ppid:6027 task_flags:0x40044c flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5248 [inline] __schedule+0x1480/0x50a0 kernel/sched/core.c:6855 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7182 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_is_held_type+0x14e/0x190 kernel/locking/lockdep.c:5945 Code: 4c 41 f7 c4 00 02 00 00 74 01 fb 65 48 8b 05 99 8a e9 06 48 3b 44 24 08 75 43 89 d8 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f 5d 3d c1 03 00 cc 90 0f 0b 90 48 c7 c7 ea 6e de 8c e8 7c 19 00 00 RSP: 0018:ffffc9000c71f310 EFLAGS: 00000282 RAX: 0000000000000001 RBX: ffff88801a180000 RCX: 6c69ef1e897fa600 RDX: 0000000000000000 RSI: ffffffff8cfbc96b RDI: ffffffff8b3e94e0 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: dffffc0000000000 R11: fffff94000241029 R12: 0000000000048205 R13: dffffc0000000000 R14: ffff88813fffa870 R15: 0000000000001000 lookup_page_ext mm/page_ext.c:254 [inline] page_ext_lookup+0xe7/0x180 mm/page_ext.c:509 page_ext_iter_begin include/linux/page_ext.h:132 [inline] page_table_check_clear+0x278/0x700 mm/page_table_check.c:78 ptep_get_and_clear_full arch/x86/include/asm/jump_label.h:-1 [inline] get_and_clear_full_ptes include/linux/pgtable.h:725 [inline] zap_present_folio_ptes mm/memory.c:1628 [inline] zap_present_ptes mm/memory.c:1710 [inline] do_zap_pte_range mm/memory.c:1811 [inline] zap_pte_range mm/memory.c:1855 [inline] zap_pmd_range mm/memory.c:1947 [inline] zap_pud_range mm/memory.c:1976 [inline] zap_p4d_range mm/memory.c:1997 [inline] unmap_page_range+0x2ec6/0x3c10 mm/memory.c:2018 unmap_single_vma mm/memory.c:2061 [inline] unmap_vmas+0x399/0x580 mm/memory.c:2105 exit_mmap+0x23b/0xb20 mm/mmap.c:1280 __mmput+0xcb/0x3d0 kernel/fork.c:1131 exit_mm+0x1da/0x2c0 kernel/exit.c:583 do_exit+0x658/0x2310 kernel/exit.c:961 do_group_exit+0x21c/0x2d0 kernel/exit.c:1114 get_signal+0x125d/0x1310 kernel/signal.c:3034 arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline] exit_to_user_mode_loop+0x87/0x4f0 kernel/entry/common.c:75 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] do_syscall_64+0x2e3/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb41646f749 RSP: 002b:00007ffe9c234ba8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: 0000000000000001 RBX: 00007fb4166c5fa8 RCX: 00007fb41646f749 RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007fb4166c5fa8 RBP: 0000000000000000 R08: 00007ffe9c234a47 R09: 000000019c234e9f R10: 00007fb4166c5fa0 R11: 0000000000000246 R12: 00007fb4166c5fac R13: 00007fb4166c5fa0 R14: 0000000000001c50 R15: 0000000000000003 task:kworker/u8:16 state:R running task stack:16736 pid:3496 tgid:3496 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: bat_events batadv_tt_purge Call Trace: context_switch kernel/sched/core.c:5248 [inline] __schedule+0x1480/0x50a0 kernel/sched/core.c:6855 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7182 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:19 [inline] RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:109 [inline] RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:127 [inline] RIP: 0010:__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:108 [inline] RIP: 0010:_raw_spin_lock_irqsave+0x60/0xf0 kernel/locking/spinlock.c:162 Code: e5 8c 48 c7 44 24 10 60 e6 c3 8a 49 89 e7 49 c1 ef 03 48 b8 f1 f1 f1 f1 00 f3 f3 f3 49 bc 00 00 00 00 00 fc ff df 4b 89 04 27 <48> c7 44 24 20 00 00 00 00 9c 8f 44 24 20 4c 8b 74 24 20 fa 41 f7 RSP: 0018:ffffc9000d11f800 EFLAGS: 00000a06 RAX: f3f3f300f1f1f1f1 RBX: ffff888052ed5980 RCX: d20c1ba0386f9b00 RDX: 0000000000000004 RSI: ffffffff8cfbc96b RDI: ffff888052ed5980 RBP: ffffc9000d11f890 R08: ffffffff8ac2b3f1 R09: ffffffff8d5aec20 R10: 0000000000000000 R11: fffffbfff1db2a2f R12: dffffc0000000000 R13: ffff888052ed5980 R14: dffffc0000000000 R15: 1ffff92001a23f00 rt_mutex_slowunlock+0xb0/0x8a0 kernel/locking/rtmutex.c:1417 spin_unlock_bh include/linux/spinlock_rt.h:110 [inline] batadv_tt_global_purge net/batman-adv/translation-table.c:2250 [inline] batadv_tt_purge+0x463/0xa10 net/batman-adv/translation-table.c:3510 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 task:syz.8.1108 state:R running task stack:24984 pid:9958 tgid:9958 ppid:6656 task_flags:0x40044c flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5248 [inline] __schedule+0x1480/0x50a0 kernel/sched/core.c:6855 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7039 preempt_schedule+0xae/0xc0 kernel/sched/core.c:7063 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 rcu_read_unlock_sched include/linux/rcupdate.h:981 [inline] pfn_valid+0x402/0x490 include/linux/mmzone.h:2197 page_table_check_clear+0x21/0x700 mm/page_table_check.c:70 ptep_get_and_clear_full arch/x86/include/asm/jump_label.h:-1 [inline] get_and_clear_full_ptes include/linux/pgtable.h:725 [inline] zap_present_folio_ptes mm/memory.c:1628 [inline] zap_present_ptes mm/memory.c:1710 [inline] do_zap_pte_range mm/memory.c:1811 [inline] zap_pte_range mm/memory.c:1855 [inline] zap_pmd_range mm/memory.c:1947 [inline] zap_pud_range mm/memory.c:1976 [inline] zap_p4d_range mm/memory.c:1997 [inline] unmap_page_range+0x2ec6/0x3c10 mm/memory.c:2018 unmap_single_vma mm/memory.c:2061 [inline] unmap_vmas+0x399/0x580 mm/memory.c:2105 exit_mmap+0x23b/0xb20 mm/mmap.c:1280 __mmput+0xcb/0x3d0 kernel/fork.c:1131 exit_mm+0x1da/0x2c0 kernel/exit.c:583 do_exit+0x658/0x2310 kernel/exit.c:961 do_group_exit+0x21c/0x2d0 kernel/exit.c:1114 get_signal+0x125d/0x1310 kernel/signal.c:3034 arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline] exit_to_user_mode_loop+0x87/0x4f0 kernel/entry/common.c:75 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] do_syscall_64+0x2e3/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f8eb6143e89 RSP: 002b:00007ffc9e3a3768 EFLAGS: 00000206 ORIG_RAX: 00000000000001b3 RAX: fffffffffffffffc RBX: 00007f8eb60c62a0 RCX: 00007f8eb6143e89 RDX: 00007f8eb60c62a0 RSI: 0000000000000058 RDI: 00007ffc9e3a37b0 RBP: 00007f8eb434d6c0 R08: 00007f8eb434d6c0 R09: 00007ffc9e3a3897 R10: 0000000000000008 R11: 0000000000000206 R12: ffffffffffffffa8 R13: 000000000000006e R14: 00007ffc9e3a37b0 R15: 00007ffc9e3a3898 task:syz.9.1098 state:R running task stack:25296 pid:9935 tgid:9933 ppid:6657 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5248 [inline] __schedule+0x1480/0x50a0 kernel/sched/core.c:6855 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7182 irqentry_exit+0x5d8/0x660 kernel/entry/common.c:216 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_release+0x2a6/0x3b0 kernel/locking/lockdep.c:5893 Code: 4d 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 75 52 f7 c3 00 02 00 00 74 01 fb 65 48 8b 05 da 12 0d 10 <48> 3b 44 24 28 75 75 48 83 c4 30 5b 41 5c 41 5d 41 5e 41 5f 5d e9 RSP: 0018:ffffc9000c6cf5f0 EFLAGS: 00000206 RAX: c528d7acf800ab00 RBX: 0000000000000202 RCX: c528d7acf800ab00 RDX: 0000000000000001 RSI: ffffffff8cfbc96b RDI: ffffffff8b3e94e0 RBP: ffff888026540b88 R08: ffffffff8ac2b3f1 R09: ffffffff8d5aec20 R10: 0000000000000000 R11: ffffed100a23dbd5 R12: 0000000000000001 R13: 0000000000000001 R14: ffffffff8d5aec20 R15: ffff888026540000 rcu_lock_release include/linux/rcupdate.h:341 [inline] rcu_read_unlock include/linux/rcupdate.h:897 [inline] rt_spin_unlock+0x15c/0x200 kernel/locking/spinlock_rt.c:82 spin_unlock_irqrestore include/linux/spinlock_rt.h:122 [inline] __skb_try_recv_datagram+0xa9/0x1b0 net/core/datagram.c:267 __unix_dgram_recvmsg+0x2d4/0xd60 net/unix/af_unix.c:2592 sock_recvmsg_nosec+0x186/0x1c0 net/socket.c:1069 ____sys_recvmsg+0x3ab/0x470 net/socket.c:2826 ___sys_recvmsg+0x1b5/0x510 net/socket.c:2870 do_recvmmsg+0x30d/0x770 net/socket.c:2965 __sys_recvmmsg net/socket.c:3039 [inline] __do_sys_recvmmsg net/socket.c:3062 [inline] __se_sys_recvmmsg net/socket.c:3055 [inline] __x64_sys_recvmmsg+0x190/0x240 net/socket.c:3055 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6315e3f749 RSP: 002b:00007f6314085038 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f6316096090 RCX: 00007f6315e3f749 RDX: 0000000000010106 RSI: 00002000000000c0 RDI: 0000000000000005 RBP: 00007f6315ec3f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f6316096128 R14: 00007f6316096090 R15: 00007ffe90bd65a8 task:kworker/u8:5 state:R running task stack:19456 pid:140 tgid:140 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: events_unbound nsim_dev_trap_report_work Call Trace: context_switch kernel/sched/core.c:5248 [inline] __schedule+0x1480/0x50a0 kernel/sched/core.c:6855 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7039 preempt_schedule+0xae/0xc0 kernel/sched/core.c:7063 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0xfd/0x110 kernel/locking/spinlock.c:194 unlock_rt_mutex_safe kernel/locking/rtmutex.c:344 [inline] rt_mutex_slowunlock+0x493/0x8a0 kernel/locking/rtmutex.c:1454 spin_unlock_bh include/linux/spinlock_rt.h:110 [inline] nsim_dev_trap_report drivers/net/netdevsim/dev.c:835 [inline] nsim_dev_trap_report_work+0x7e5/0xbc0 drivers/net/netdevsim/dev.c:866 process_one_work kernel/workqueue.c:3263 [inline] process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3346 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 rcu: rcu_preempt kthread starved for 10269 jiffies! g41329 f0x0 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:23264 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5248 [inline] __schedule+0x1480/0x50a0 kernel/sched/core.c:6855 __schedule_loop kernel/sched/core.c:6937 [inline] schedule+0x165/0x360 kernel/sched/core.c:6952 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+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82 Code: 83 c9 03 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 23 f3 27 00 f3 0f 1e fa fb f4 58 c9 03 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffffff8d207d80 EFLAGS: 000002c2 RAX: 219ab05afcf7a000 RBX: ffffffff8195f82a RCX: 219ab05afcf7a000 RDX: 0000000000000001 RSI: ffffffff8cde6eea RDI: ffffffff8b3e94e0 RBP: ffffffff8d207ea8 R08: ffff8880b8833b5b R09: 1ffff1101710676b R10: dffffc0000000000 R11: ffffed101710676c R12: ffffffff8ed95170 R13: 1ffffffff1a60650 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888126d81000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f850322642d CR3: 0000000035c42000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x73/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x1ea/0x520 kernel/sched/idle.c:332 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430 rest_init+0x2de/0x300 init/main.c:757 start_kernel+0x3ae/0x410 init/main.c:1111 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x147