rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (1 GPs behind) idle=f19c/1/0x4000000000000000 softirq=22937/22996 fqs=0
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6590/1:b..l
rcu: (detected by 1, t=10624 jiffies, g=17253, q=1423 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 1137 Comm: kworker/u8:7 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Workqueue: writeback wb_workfn (flush-8:0)
RIP: 0010:match_held_lock+0x0/0xb0 kernel/locking/lockdep.c:5305
Code: 67 48 0f b9 3a 90 31 db 48 89 d8 5b 41 5e 41 5f c3 cc cc cc cc cc 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <41> 56 53 bb 01 00 00 00 48 39 77 10 74 6a 81 7f 20 00 00 20 00 72
RSP: 0018:ffffc90000007c30 EFLAGS: 00000083
RAX: 0000000000000008 RBX: ffff888028f28bf8 RCX: 0000000000010004
RDX: ffff888028f28000 RSI: ffff88802b1092c0 RDI: ffff888028f28bf8
RBP: 00000000ffffffff R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000000f7c R12: 0000000000000046
R13: ffff888028f28000 R14: ffff88802b1092c0 R15: 0000000000000004
FS: 0000000000000000(0000) GS:ffff888125454000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f991bac8040 CR3: 0000000072f24000 CR4: 00000000003526f0
Call Trace:
__lock_is_held kernel/locking/lockdep.c:5601 [inline]
lock_is_held_type+0x89/0x150 kernel/locking/lockdep.c:5940
lock_is_held include/linux/lockdep.h:249 [inline]
advance_sched+0xe7/0xc90 net/sched/sch_taprio.c:931
__run_hrtimer kernel/time/hrtimer.c:1785 [inline]
__hrtimer_run_queues+0x53a/0xcc0 kernel/time/hrtimer.c:1849
hrtimer_interrupt+0x42b/0x1010 kernel/time/hrtimer.c:1911
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline]
__sysvec_apic_timer_interrupt+0x102/0x460 arch/x86/kernel/apic/apic.c:1062
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1056
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xce5/0x12c0 kernel/smp.c:877
Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 d4 eb 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 7f e7 0b 00 eb 38 f3 90 <42> 0f b6 04 2b 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 63 e7
RSP: 0018:ffffc90004a7e220 EFLAGS: 00000293
RAX: ffffffff81b9d88d RBX: 1ffff110170e813d RCX: ffff888028f28000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90004a7e350 R08: ffff888059fb8b87 R09: 1ffff1100b3f7170
R10: dffffc0000000000 R11: ffffffff81787c90 R12: ffff8880b87409e8
R13: dffffc0000000000 R14: ffff8880b863c000 R15: 0000000000000001
on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043
__flush_tlb_multi arch/x86/include/asm/paravirt.h:57 [inline]
flush_tlb_multi arch/x86/mm/tlb.c:1382 [inline]
flush_tlb_mm_range+0x5c3/0x10c0 arch/x86/mm/tlb.c:1472
flush_tlb_page arch/x86/include/asm/tlbflush.h:323 [inline]
ptep_clear_flush+0x120/0x170 mm/pgtable-generic.c:103
page_vma_mkclean_one+0x438/0x780 mm/rmap.c:1132
page_mkclean_one+0x1d8/0x2b0 mm/rmap.c:1180
__rmap_walk_file+0x467/0x620 mm/rmap.c:3056
rmap_walk mm/rmap.c:3100 [inline]
folio_mkclean+0x2bb/0x3d0 mm/rmap.c:1212
folio_clear_dirty_for_io+0x1a5/0x710 mm/page-writeback.c:2909
mpage_submit_folio+0x86/0x2b0 fs/ext4/inode.c:2071
mpage_process_page_bufs+0x6d5/0x8e0 fs/ext4/inode.c:2201
mpage_prepare_extent_to_map+0xe1b/0x16f0 fs/ext4/inode.c:2740
ext4_do_writepages+0xbca/0x46e0 fs/ext4/inode.c:2881
ext4_writepages+0x241/0x3b0 fs/ext4/inode.c:3029
do_writepages+0x32e/0x550 mm/page-writeback.c:2575
__writeback_single_inode+0x133/0x11a0 fs/fs-writeback.c:1762
writeback_sb_inodes+0x992/0x1a20 fs/fs-writeback.c:2054
__writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2130
wb_writeback+0x46a/0xb70 fs/fs-writeback.c:2241
wb_check_old_data_flush fs/fs-writeback.c:2345 [inline]
wb_do_writeback fs/fs-writeback.c:2398 [inline]
wb_workfn+0xb4c/0xf50 fs/fs-writeback.c:2426
process_one_work kernel/workqueue.c:3276 [inline]
process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
task:dhcpcd-run-hook state:R running task stack:26784 pid:6590 tgid:6590 ppid:6585 task_flags:0x400040 flags:0x00080001
Call Trace:
context_switch kernel/sched/core.c:5298 [inline]
__schedule+0x15dd/0x52d0 kernel/sched/core.c:6911
preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:7095
preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
__raw_spin_unlock include/linux/spinlock_api_smp.h:169 [inline]
_raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:389 [inline]
wp_page_copy mm/memory.c:3881 [inline]
do_wp_page+0x42bf/0x5a00 mm/memory.c:4241
handle_pte_fault mm/memory.c:6333 [inline]
__handle_mm_fault mm/memory.c:6455 [inline]
handle_mm_fault+0x1520/0x3310 mm/memory.c:6624
do_user_addr_fault+0xa73/0x1340 arch/x86/mm/fault.c:1334
handle_page_fault arch/x86/mm/fault.c:1474 [inline]
exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0033:0x7f120491ecdf
RSP: 002b:00007ffd7dc7ca30 EFLAGS: 00010246
RAX: 00000000000000c3 RBX: 0000558493a42e60 RCX: 0000558493a4a2a0
RDX: 00007f1204993450 RSI: 0000000000000001 RDI: 0000558493a4f6d0
RBP: 0000000000000001 R08: 00007ffd7dc7ca30 R09: 0000558493a42e60
R10: 0000000000000000 R11: 0000000000000202 R12: 0000558493a4a040
R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000000
rcu: rcu_preempt kthread starved for 10624 jiffies! g17253 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:27744 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5298 [inline]
__schedule+0x15dd/0x52d0 kernel/sched/core.c:6911
__schedule_loop kernel/sched/core.c:6993 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7008
schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095
rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
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: 5192 Comm: udevd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xce5/0x12c0 kernel/smp.c:877
Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 d4 eb 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 7f e7 0b 00 eb 38 f3 90 <42> 0f b6 04 2b 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 63 e7
RSP: 0018:ffffc90003217580 EFLAGS: 00000293
RAX: ffffffff81b9d88d RBX: 1ffff110170c8525 RCX: ffff88807b863d00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900032176a8 R08: ffffffff9011deb7 R09: 1ffffffff2023bd6
R10: dffffc0000000000 R11: fffffbfff2023bd7 R12: ffff8880b8642928
R13: dffffc0000000000 R14: ffff8880b873c000 R15: 0000000000000000
FS: 00007fa7fd964880(0000) GS:ffff888125554000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd7dc7ca28 CR3: 000000007b70e000 CR4: 00000000003526f0
Call Trace:
on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043
__flush_tlb_multi arch/x86/include/asm/paravirt.h:57 [inline]
flush_tlb_multi arch/x86/mm/tlb.c:1382 [inline]
flush_tlb_mm_range+0x5c3/0x10c0 arch/x86/mm/tlb.c:1472
dup_mmap+0x17a2/0x1d90 mm/mmap.c:1906
dup_mm kernel/fork.c:1531 [inline]
copy_mm+0x13b/0x4a0 kernel/fork.c:1583
copy_process+0x18b6/0x3cd0 kernel/fork.c:2223
kernel_clone+0x248/0x8e0 kernel/fork.c:2653
__do_sys_clone kernel/fork.c:2794 [inline]
__se_sys_clone kernel/fork.c:2778 [inline]
__x64_sys_clone+0x1b6/0x230 kernel/fork.c:2778
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa7fd2f1636
Code: 89 df e8 6d e8 f6 ff 45 31 c0 31 d2 31 f6 64 48 8b 04 25 10 00 00 00 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 52 89 c5 85 c0 75 31 64 48 8b 04 25 10 00 00
RSP: 002b:00007ffea3ba2bb0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007ffea3ba2bb8 RCX: 00007fa7fd2f1636
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 0000564822f94910 R08: 0000000000000000 R09: 0000564822f9c8e0
R10: 00007fa7fd964b50 R11: 0000000000000246 R12: 00007ffea3ba2f70
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000