rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=e3ec/1/0x4000000000000000 softirq=36772/36778 fqs=0 rcu: (detected by 1, t=10506 jiffies, g=29381, q=378 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 6513 Comm: syz-executor Not tainted 6.14.0-syzkaller-12966-ga2cc6ff5ec8f #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:lockdep_recursion_finish kernel/locking/lockdep.c:472 [inline] RIP: 0010:lock_acquire+0x11a/0x2f0 kernel/locking/lockdep.c:5868 Code: 48 89 df 8b 74 24 04 44 89 fa 44 89 e9 45 89 e0 6a 00 6a 00 6a 00 ff b4 24 90 00 00 00 ff 74 24 28 e8 6a 02 00 00 48 83 c4 28 <48> c7 c7 66 c6 4f 8e e8 0a 51 91 0a b8 ff ff ff ff 65 0f c1 05 9d RSP: 0018:ffffc90000007be0 EFLAGS: 00000092 RAX: 0000000000000001 RBX: ffff888059823300 RCX: 1e173af68bbdaf00 RDX: 0000000000000001 RSI: ffff888031c364f0 RDI: ffff888031c35a00 RBP: ffffffff93687020 R08: 0000000000000001 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 R13: 0000000000000000 R14: 0000000000000046 R15: 0000000000000000 FS: 000055556d33f500(0000) GS:ffff888124f99000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055556d362608 CR3: 000000003055a000 CR4: 0000000000350ef0 Call Trace: __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] advance_sched+0xab/0xca0 net/sched/sch_taprio.c:924 __run_hrtimer kernel/time/hrtimer.c:1791 [inline] __hrtimer_run_queues+0x5a8/0xd40 kernel/time/hrtimer.c:1855 hrtimer_interrupt+0x403/0xa40 kernel/time/hrtimer.c:1917 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x112/0x420 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:__rcu_read_unlock+0x5/0x110 kernel/rcu/tree_plugin.h:431 Code: e1 07 80 c1 03 38 c1 7c aa 4c 89 ff e8 94 f9 83 00 eb a0 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 <41> 57 41 56 41 55 41 54 53 49 bc 00 00 00 00 00 fc ff df 65 4c 8b RSP: 0018:ffffc90002faf0b8 EFLAGS: 00000286 RAX: 1e173af68bbdaf00 RBX: ffffc90002faf1a0 RCX: 0000000000000000 RDX: dffffc0000000000 RSI: ffffffff8e4fc666 RDI: ffffffff8ca1b140 RBP: dffffc0000000001 R08: ffffc90002faff00 R09: ffffc90002faf1f0 R10: dffffc0000000000 R11: fffff520005f5e40 R12: ffffc90002faf1b0 R13: dffffc0000000000 R14: ffffc90002faff10 R15: ffffffff816dfbc8 rcu_read_unlock include/linux/rcupdate.h:873 [inline] class_rcu_destructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0x1aa4/0x23b0 arch/x86/kernel/unwind_orc.c:680 arch_stack_walk+0x11e/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x11a/0x1d0 kernel/stacktrace.c:122 save_stack+0xfc/0x1f0 mm/page_owner.c:156 __reset_page_owner+0x76/0x1e0 mm/page_owner.c:308 reset_page_owner include/linux/page_owner.h:25 [inline] free_pages_prepare mm/page_alloc.c:1262 [inline] free_unref_folios+0xe0e/0x17f0 mm/page_alloc.c:2737 folios_put_refs+0x70a/0x800 mm/swap.c:992 folio_batch_release include/linux/pagevec.h:101 [inline] shmem_undo_range+0x595/0x1820 mm/shmem.c:1125 shmem_truncate_range mm/shmem.c:1237 [inline] shmem_evict_inode+0x29d/0xa80 mm/shmem.c:1365 evict+0x4fb/0x9b0 fs/inode.c:810 __dentry_kill+0x20d/0x630 fs/dcache.c:660 dput+0x19f/0x2b0 fs/dcache.c:902 __fput+0x60b/0x9f0 fs/file_table.c:473 task_work_run+0x253/0x310 kernel/task_work.c:227 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] exit_to_user_mode_loop kernel/entry/common.c:114 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline] __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline] syscall_exit_to_user_mode+0x13f/0x340 kernel/entry/common.c:218 do_syscall_64+0x100/0x230 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f36e2d8bdca Code: 48 3d 00 f0 ff ff 77 48 c3 0f 1f 80 00 00 00 00 48 83 ec 18 89 7c 24 0c e8 43 91 02 00 8b 7c 24 0c 89 c2 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 36 89 d7 89 44 24 0c e8 a3 91 02 00 8b 44 24 RSP: 002b:00007ffef0ca0ee0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007f36e2d8bdca RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00007ffef0ca0f3c R08: 0000000000000000 R09: 00007ffef0ca0c47 R10: 0000000000000000 R11: 0000000000000293 R12: 000000000000007a R13: 00000000000927c0 R14: 000000000003ddd8 R15: 00007ffef0ca0f90 rcu: rcu_preempt kthread starved for 10506 jiffies! g29381 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R running task stack:26688 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5382 [inline] __schedule+0x1b88/0x5240 kernel/sched/core.c:6767 __schedule_loop kernel/sched/core.c:6845 [inline] schedule+0x163/0x360 kernel/sched/core.c:6860 schedule_timeout+0x15b/0x2b0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x2e1/0x1340 kernel/rcu/tree.c:2046 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2248 kthread+0x7b9/0x940 kernel/kthread.c:464 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 52 Comm: kworker/u8:3 Not tainted 6.14.0-syzkaller-12966-ga2cc6ff5ec8f #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Workqueue: netns cleanup_net RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:smp_call_function_single+0x461/0x1990 kernel/smp.c:679 Code: 55 22 0c 00 41 83 e4 01 75 16 e8 0a 1e 0c 00 4d 89 fc 44 8b 7c 24 24 eb 46 e8 fb 1d 0c 00 eb 3f 4d 89 fc 44 8b 7c 24 24 f3 90 <42> 0f b6 04 2b 84 c0 75 10 41 f7 06 01 00 00 00 74 1e e8 d8 1d 0c RSP: 0018:ffffc90000be75c0 EFLAGS: 00000293 RAX: ffffffff81b739a8 RBX: 1ffff9200017ced5 RCX: ffff888020ecda00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90000be7758 R08: ffffffff81b7396b R09: 1ffff9200017ce84 R10: dffffc0000000000 R11: fffff5200017ce85 R12: ffffffff93687020 R13: dffffc0000000000 R14: ffffc90000be76a8 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888125099000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005605daeb5600 CR3: 0000000033bfa000 CR4: 0000000000350ef0 Call Trace: rcu_barrier+0x327/0x530 kernel/rcu/tree.c:3826 netdev_wait_allrefs_any net/core/dev.c:11206 [inline] netdev_run_todo+0x902/0xf30 net/core/dev.c:11298 default_device_exit_batch+0x804/0x880 net/core/dev.c:12528 ops_exit_list net/core/net_namespace.c:177 [inline] cleanup_net+0x8b1/0xd60 net/core/net_namespace.c:654 process_one_work kernel/workqueue.c:3238 [inline] process_scheduled_works+0xac5/0x18e0 kernel/workqueue.c:3319 worker_thread+0x870/0xd50 kernel/workqueue.c:3400 kthread+0x7b9/0x940 kernel/kthread.c:464 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:153 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245