rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P1110/1:b.el rcu: (detected by 0, t=10517 jiffies, g=8929, q=710 ncpus=2) task:kworker/u8:6 state:R running task stack:23592 pid:1110 tgid:1110 ppid:2 task_flags:0x24248060 flags:0x00080000 Workqueue: writeback wb_workfn (flush-8:0) Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7190 irqentry_exit+0x1d8/0x8c0 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+0x107/0x150 kernel/locking/lockdep.c:5945 Code: 00 00 b8 ff ff ff ff 65 0f c1 05 5c f0 3a 08 83 f8 01 75 2d 9c 58 f6 c4 02 75 43 48 f7 04 24 00 02 00 00 74 01 fb 48 83 c4 08 <44> 89 e8 5b 5d 41 5c 41 5d 41 5e 41 5f e9 87 2c 03 00 45 31 ed eb RSP: 0018:ffffc9000416edd0 EFLAGS: 00000292 RAX: 0000000000000046 RBX: ffff8880284a30b8 RCX: 0000000000000001 RDX: 0000000000000000 RSI: ffffffff8daa7ee5 RDI: ffffffff8bf2b400 RBP: ffff888074dbbe98 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: ffff8880284a2ff0 R12: ffff8880284a24c0 R13: 0000000000000000 R14: 00000000ffffffff R15: 0000000000000006 lock_is_held include/linux/lockdep.h:249 [inline] xa_entry include/linux/xarray.h:1226 [inline] xas_reload include/linux/xarray.h:1624 [inline] find_get_entry mm/filemap.c:2079 [inline] filemap_get_folios_tag+0x6c2/0xae0 mm/filemap.c:2332 mpage_prepare_extent_to_map+0x399/0x1510 fs/ext4/inode.c:2639 ext4_do_writepages+0xd1b/0x3c80 fs/ext4/inode.c:2930 ext4_writepages+0x37a/0x7d0 fs/ext4/inode.c:3026 do_writepages+0x27a/0x600 mm/page-writeback.c:2598 __writeback_single_inode+0x168/0x14a0 fs/fs-writeback.c:1737 writeback_sb_inodes+0x72e/0x1ce0 fs/fs-writeback.c:2030 __writeback_inodes_wb+0xf8/0x2d0 fs/fs-writeback.c:2107 wb_writeback+0x799/0xae0 fs/fs-writeback.c:2218 wb_check_old_data_flush fs/fs-writeback.c:2322 [inline] wb_do_writeback fs/fs-writeback.c:2375 [inline] wb_workfn+0x8a0/0xbb0 fs/fs-writeback.c:2403 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 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 9334 jiffies! g8929 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:28440 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1139/0x6150 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:6960 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 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: 5827 Comm: udevd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0xdfd/0x15e0 kernel/smp.c:877 Code: 57 48 8b 54 24 10 4c 89 74 24 10 49 89 d5 48 89 d5 48 89 54 24 18 49 c1 ed 03 83 e5 07 4d 01 e5 83 c5 03 e8 35 5d 0c 00 f3 90 <41> 0f b6 45 00 40 38 c5 7c 08 84 c0 0f 85 b6 05 00 00 8b 43 08 31 RSP: 0000:ffffc9000412f8a8 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff8880b8540cc0 RCX: ffffffff81b28bb1 RDX: ffff888077b1c980 RSI: ffffffff81b28b8b RDI: 0000000000000005 RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: ffff888077b1d4b0 R12: dffffc0000000000 R13: ffffed10170a8199 R14: 0000000000000001 R15: 0000000000000001 FS: 00007f44587e7880(0000) GS:ffff8881248f5000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055d6d5f21fe8 CR3: 00000000723c5000 CR4: 00000000003526f0 Call Trace: on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1043 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1382 [inline] flush_tlb_mm_range+0x2f0/0x12c0 arch/x86/mm/tlb.c:1472 flush_tlb_page arch/x86/include/asm/tlbflush.h:324 [inline] ptep_clear_flush+0x136/0x180 mm/pgtable-generic.c:103 wp_page_copy mm/memory.c:3785 [inline] do_wp_page+0x171f/0x5010 mm/memory.c:4180 handle_pte_fault mm/memory.c:6289 [inline] __handle_mm_fault+0x1bd2/0x2bb0 mm/memory.c:6411 handle_mm_fault+0x3fe/0xad0 mm/memory.c:6580 do_user_addr_fault+0x60c/0x1370 arch/x86/mm/fault.c:1336 handle_page_fault arch/x86/mm/fault.c:1476 [inline] exc_page_fault+0x64/0xc0 arch/x86/mm/fault.c:1532 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0033:0x7f44580b5db7 Code: 00 00 00 41 55 48 89 d0 49 89 fd 41 54 49 89 f4 53 4c 89 c3 48 83 ec 10 48 39 4f 60 0f 84 c1 00 00 00 42 f6 44 01 08 01 74 59 <48> 83 61 08 fe 48 3d ff 03 00 00 76 69 49 8b 55 70 49 8d 75 60 48 RSP: 002b:00007ffc72ea2750 EFLAGS: 00010202 RAX: 0000000000006010 RBX: 00000000000001f0 RCX: 000055d6d5f21fe0 RDX: 0000000000006010 RSI: 000055d6d5f1bfd0 RDI: 00007f44581f1ac0 RBP: 00007f44581f1ac0 R08: 00000000000001f0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 000055d6d5f1bfd0 R13: 00007f44581f1ac0 R14: 00000000000001f0 R15: 00007f44581f1ac0