rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (1 GPs behind) idle=c6d4/1/0x4000000000000000 softirq=16614/16640 fqs=214
rcu: (detected by 1, t=10505 jiffies, g=14905, q=1368 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 5854 Comm: kworker/0:4 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Workqueue: events_power_efficient gc_worker
RIP: 0010:hlock_class kernel/locking/lockdep.c:234 [inline]
RIP: 0010:check_wait_context kernel/locking/lockdep.c:4898 [inline]
RIP: 0010:__lock_acquire+0x3f9/0x2de0 kernel/locking/lockdep.c:5238
Code: 49 09 cc 49 09 d4 48 8d 2c c5 00 00 00 00 4c 01 ed 4c 89 6c 24 18 4d 89 64 c5 20 41 81 e4 ff 1f 00 00 4c 0f a3 25 37 d7 f7 12 <73> 15 49 69 c4 c8 00 00 00 48 8d 80 d0 44 3c 94 4c 8b 74 24 08 eb
RSP: 0018:ffffc90000007b00 EFLAGS: 00000003
RAX: 000000000000000f RBX: 0000000000000000 RCX: 000000000000090d
RDX: 0000000000044000 RSI: 0000000000004000 RDI: 0400000000000000
RBP: ffff888026f9ab68 R08: ffffffff89ee7a02 R09: 0000000000000001
R10: dffffc0000000000 R11: ffffffff89ee7940 R12: 000000000000090d
R13: ffff888026f9aaf0 R14: 0000000000000003 R15: ffff888026f99f40
FS: 0000000000000000(0000) GS:ffff888124cc7000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005617f8bb3a08 CR3: 000000000eb48000 CR4: 00000000003526f0
Call Trace:
lock_acquire+0x115/0x350 kernel/locking/lockdep.c:5942
__raw_spin_lock include/linux/spinlock_api_smp.h:190 [inline]
_raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:173
spin_lock include/linux/spinlock.h:347 [inline]
advance_sched+0xc2/0xc80 net/sched/sch_taprio.c:931
__run_hrtimer kernel/time/hrtimer.c:2074 [inline]
__hrtimer_run_queues+0x3bc/0xa10 kernel/time/hrtimer.c:2131
hrtimer_interrupt+0x4cd/0xaa0 kernel/time/hrtimer.c:2250
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline]
__sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1068
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1062
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:seqcount_lockdep_reader_access+0xed/0x100 include/linux/seqlock.h:76
Code: 00 75 11 e8 35 78 c6 f7 4d 85 f6 75 16 e8 2b 78 c6 f7 eb 15 e8 24 78 c6 f7 e8 0f 4f e5 01 4d 85 f6 74 ea e8 15 78 c6 f7 fb 5b <41> 5e c3 cc cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90
RSP: 0018:ffffc90003517970 EFLAGS: 00000293
RAX: ffffffff8a01967b RBX: 0000000000000001 RCX: ffff888026f99f40
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90003517ad0 R08: ffffffff907a627f R09: 1ffffffff20f4c4f
R10: dffffc0000000000 R11: fffffbfff20f4c50 R12: dffffc0000000000
R13: ffffffff818fc66a R14: 0000000000000200 R15: 0000000000014059
nf_conntrack_get_ht include/net/netfilter/nf_conntrack.h:348 [inline]
gc_worker+0x31b/0x1890 net/netfilter/nf_conntrack_core.c:1534
process_one_work kernel/workqueue.c:3396 [inline]
process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
rcu: rcu_preempt kthread starved for 9435 jiffies! g14905 f0x0 RCU_GP_WAIT_FQS(5) ->state=R ->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:27496 pid:17 tgid:17 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5533 [inline]
__schedule+0x17db/0x58f0 kernel/sched/core.c:7284
__schedule_loop kernel/sched/core.c:7361 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7376
schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2122
rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2330
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 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: 59 Comm: kworker/u8:4 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Workqueue: writeback wb_workfn (flush-8:0)
RIP: 0010:csd_lock_wait kernel/smp.c:363 [inline]
RIP: 0010:csd_lock kernel/smp.c:396 [inline]
RIP: 0010:smp_call_function_many_cond+0x61e/0x1500 kernel/smp.c:944
Code: b6 04 04 84 c0 0f 85 d5 03 00 00 44 8b 3b 44 89 fe 83 e6 01 31 ff e8 01 59 0c 00 41 83 e7 01 75 07 e8 f6 53 0c 00 eb 3f f3 90 <48> b8 00 00 00 00 00 fc ff df 41 0f b6 04 04 84 c0 75 0f f7 03 01
RSP: 0000:ffffc9000200e460 EFLAGS: 00000293
RAX: ffffffff81bbbabe RBX: ffff8880b8643708 RCX: ffff88801cf53e80
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000200e5b0 R08: ffff88801cf5541f R09: 1ffff110039eaa83
R10: dffffc0000000000 R11: ffffffff8179fc60 R12: 1ffff110170c86e1
R13: 0000000000000000 R14: ffff8880b8643700 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff888124dc7000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000056982470 CR3: 0000000073ca8000 CR4: 00000000003526f0
Call Trace:
__flush_tlb_multi arch/x86/include/asm/paravirt.h:46 [inline]
flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline]
flush_tlb_mm_range+0x8ff/0x1090 arch/x86/mm/tlb.c:1435
flush_tlb_page arch/x86/include/asm/tlbflush.h:352 [inline]
ptep_clear_flush+0x120/0x170 mm/pgtable-generic.c:104
page_vma_mkclean_one+0x4b9/0x840 mm/rmap.c:1146
page_mkclean_one+0x20c/0x2e0 mm/rmap.c:1194
__rmap_walk_file+0x4cd/0x6a0 mm/rmap.c:3120
rmap_walk mm/rmap.c:3164 [inline]
folio_mkclean+0x2d5/0x3f0 mm/rmap.c:1226
folio_clear_dirty_for_io+0x190/0x820 mm/page-writeback.c:2903
mpage_submit_folio+0x83/0x2a0 fs/ext4/inode.c:2075
mpage_map_and_submit_buffers fs/ext4/inode.c:2331 [inline]
mpage_map_and_submit_extent fs/ext4/inode.c:2515 [inline]
ext4_do_writepages+0x203d/0x4770 fs/ext4/inode.c:2938
ext4_writepages+0x241/0x3b0 fs/ext4/inode.c:3032
do_writepages+0x338/0x560 mm/page-writeback.c:2560
__writeback_single_inode+0x136/0x1220 fs/fs-writeback.c:1803
writeback_sb_inodes+0x9de/0x1b00 fs/fs-writeback.c:2114
__writeback_inodes_wb+0x114/0x240 fs/fs-writeback.c:2190
wb_writeback+0x42f/0xad0 fs/fs-writeback.c:2301
wb_check_old_data_flush fs/fs-writeback.c:2405 [inline]
wb_do_writeback fs/fs-writeback.c:2484 [inline]
wb_workfn+0xc92/0x10f0 fs/fs-writeback.c:2512
process_one_work kernel/workqueue.c:3396 [inline]
process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245