rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	0-...!: (1 ticks this GP) idle=ff1/1/0x4000000000000002 softirq=11329/11329 fqs=7 
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4277/1:b..l
	(detected by 1, t=10502 jiffies, g=14193, q=348)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 5550 Comm: syz.3.25 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:check_kcov_mode kernel/kcov.c:172 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:227 [inline]
RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x1b/0x80 kernel/kcov.c:293
Code: 02 18 4a 89 44 02 20 48 ff c1 48 89 0a c3 90 48 8b 04 24 65 48 8b 0d 44 36 89 7e 65 8b 15 45 36 89 7e 81 e2 00 01 ff 00 74 11 <81> fa 00 01 00 00 75 5b 83 b9 34 16 00 00 00 74 52 8b 91 10 16 00
RSP: 0018:ffffc90000006f98 EFLAGS: 00000006
RAX: ffffffff819bcff6 RBX: 0000000000000001 RCX: ffff8880612a1dc0
RDX: 0000000000000100 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900000070d0 R08: ffffc90000007057 R09: ffffc90000007040
R10: dffffc0000000000 R11: fffff52000000e0b R12: 1ffff92000000e04
R13: ffffc90000007120 R14: 0000000000000008 R15: ffff88801ec45f80
FS:  000055556d017500(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fbb738bc640 CR3: 000000005a4fb000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 __perf_output_begin kernel/events/ring_buffer.c:170 [inline]
 perf_output_begin_forward+0x1a6/0xa40 kernel/events/ring_buffer.c:271
 __perf_event_output kernel/events/core.c:7804 [inline]
 perf_event_output_forward+0x19b/0x2e0 kernel/events/core.c:7822
 __perf_event_overflow+0x364/0x530 kernel/events/core.c:9515
 perf_swevent_overflow kernel/events/core.c:9591 [inline]
 perf_swevent_event+0x4ad/0x530 kernel/events/core.c:9629
 perf_tp_event+0x383/0xbf0 kernel/events/core.c:10047
 perf_trace_run_bpf_submit+0xf3/0x1c0 kernel/events/core.c:10021
 perf_trace_preemptirq_template+0x2aa/0x360 include/trace/events/preemptirq.h:14
 trace_irq_enable_rcuidle+0x108/0x180 include/trace/events/preemptirq.h:40
 trace_hardirqs_on+0x57/0x80 kernel/trace/trace_preemptirq.c:44
 asm_sysvec_irq_work+0x16/0x20 arch/x86/include/asm/idtentry.h:713
RIP: 0010:rcu_read_unlock_special+0x7f/0x4a0 kernel/rcu/tree_plugin.h:674
Code: eb 03 48 b8 f1 f1 f1 f1 f8 f2 f2 f2 4a 89 04 2b 42 c7 44 2b 08 f8 f3 f3 f3 65 44 8b 35 d2 df 9c 7e 41 f7 c6 00 00 f0 00 74 40 <48> c7 44 24 20 0e 36 e0 45 4a c7 04 2b 00 00 00 00 42 c7 44 2b 08
RSP: 0018:ffffc90000007780 EFLAGS: 00000206
RAX: 7bbcbf46a7bab000 RBX: 1ffff92000000ef4 RCX: 7bbcbf46a7bab000
RDX: dffffc0000000000 RSI: ffffffff8a2b3100 RDI: ffffffff8a7a0700
RBP: ffffc90000007860 R08: ffffffff901d615f R09: 1ffffffff203ac2b
R10: dffffc0000000000 R11: fffffbfff203ac2c R12: ffffffff8c323800
R13: dffffc0000000000 R14: 0000000000000246 R15: 0000000000000001
 __rcu_read_unlock+0x78/0xd0 kernel/rcu/tree_plugin.h:422
 rcu_read_unlock include/linux/rcupdate.h:772 [inline]
 __ip_queue_xmit+0x1242/0x1c00 net/ipv4/ip_output.c:539
 __tcp_transmit_skb+0x1d11/0x3200 net/ipv4/tcp_output.c:1404
 tcp_delack_timer_handler+0x32e/0x730 net/ipv4/tcp_timer.c:314
 tcp_delack_timer+0x188/0x2e0 net/ipv4/tcp_timer.c:341
 call_timer_fn+0x17b/0x540 kernel/time/timer.c:1648
 expire_timers kernel/time/timer.c:1699 [inline]
 __run_timers+0x53e/0x800 kernel/time/timer.c:1970
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1983
 handle_softirqs+0x339/0x830 kernel/softirq.c:576
 __do_softirq kernel/softirq.c:610 [inline]
 invoke_softirq kernel/softirq.c:450 [inline]
 __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:kasan_quarantine_put+0x84/0x220 mm/kasan/quarantine.c:234
Code: e8 51 05 c1 ff 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 0f 85 83 00 00 00 41 f7 c7 00 02 00 00 74 01 fb 31 c0 <48> 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f c3 48 8d 80 40 62 03 00 45
RSP: 0018:ffffc90002f4fd00 EFLAGS: 00000206
RAX: 7bbcbf46a7bab001 RBX: ffff88807a13a5b0 RCX: 7bbcbf46a7bab000
RDX: dffffc0000000000 RSI: ffffffff8a2b3100 RDI: ffffffff8a7a0700
RBP: ffffc90002f4fd98 R08: ffff8880b903b30b R09: 1ffff11017207661
R10: dffffc0000000000 R11: ffffed1017207662 R12: ffff888016de9000
R13: ffff88807a13a5b0 R14: 00000000000d95a0 R15: 0000000000000282
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1710 [inline]
 slab_free_freelist_hook+0xea/0x170 mm/slub.c:1736
 slab_free mm/slub.c:3504 [inline]
 kmem_cache_free+0x8f/0x210 mm/slub.c:3520
 file_free fs/file_table.c:55 [inline]
 __fput+0x627/0x930 fs/file_table.c:324
 task_work_run+0x125/0x1a0 kernel/task_work.c:188
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f0c45dafef9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffcc50c75b8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f0c4601cda0 RCX: 00007f0c45dafef9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f0c4601cda0 R08: 00007f0c4601b038 R09: 0000000000000000
R10: 000000000003fdcc R11: 0000000000000246 R12: 000000000001d78c
R13: 00007f0c4601b09c R14: 000000000001d4b7 R15: 00007f0c4601b090
 </TASK>
task:kworker/u4:5    state:R  running task     stack:20528 pid: 4277 ppid:     2 flags:0x00004000
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6799
 irqentry_exit+0x63/0x70 kernel/entry/common.c:432
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:clear_page_dirty_for_io+0x79d/0x9f0 mm/page-writeback.c:2762
Code: e9 0a d8 ff 49 ff ce e9 39 fe ff ff e8 dc 0a d8 ff e8 77 9e 1b 08 48 85 db 0f 84 53 ff ff ff e8 c9 0a d8 ff fb 48 8b 7c 24 10 <be> 06 00 00 00 e8 c9 f5 06 00 48 c7 c0 30 fa 89 8d 48 c1 e8 03 42
RSP: 0018:ffffc9000302ec40 EFLAGS: 00000293
RAX: ffffffff81a12b47 RBX: 0000000000000200 RCX: ffff88802c179dc0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffea0001c60540
RBP: ffffc9000302ed28 R08: ffffffff901d6187 R09: 1ffffffff203ac30
R10: dffffc0000000000 R11: fffffbfff203ac31 R12: ffff8880236d4060
R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000000
 mpage_submit_page+0x8a/0x210 fs/ext4/inode.c:2095
 mpage_process_page_bufs+0x6d8/0x8b0 fs/ext4/inode.c:2229
 mpage_prepare_extent_to_map+0xbc2/0xfe0 fs/ext4/inode.c:2657
 ext4_writepages+0xa9a/0x2df0 fs/ext4/inode.c:2785
 do_writepages+0x476/0x6e0 mm/page-writeback.c:2386
 __writeback_single_inode+0x153/0xda0 fs/fs-writeback.c:1657
 writeback_sb_inodes+0xa4e/0x1680 fs/fs-writeback.c:1940
 __writeback_inodes_wb+0x12a/0x3f0 fs/fs-writeback.c:2011
 wb_writeback+0x46f/0xbe0 fs/fs-writeback.c:2116
 wb_check_old_data_flush fs/fs-writeback.c:2216 [inline]
 wb_do_writeback fs/fs-writeback.c:2269 [inline]
 wb_workfn+0xb15/0xf20 fs/fs-writeback.c:2298
 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
 worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
rcu: rcu_preempt kthread timer wakeup didn't happen for 10487 jiffies! g14193 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: 	Possible timer handling issue on cpu=1 timer-softirq=3971
rcu: rcu_preempt kthread starved for 10488 jiffies! g14193 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27120 pid:   15 ppid:     2 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117
 rcu_gp_fqs_loop+0x2be/0x11d0 kernel/rcu/tree.c:1972
 rcu_gp_kthread+0x9b/0x370 kernel/rcu/tree.c:2145
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
NMI backtrace for cpu 1
CPU: 1 PID: 5562 Comm: dhcpcd-run-hook Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Call Trace:
 <IRQ>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:166 [inline]
 rcu_check_gp_kthread_starvation+0x1cd/0x250 kernel/rcu/tree_stall.h:487
 print_other_cpu_stall+0x1110/0x1270 kernel/rcu/tree_stall.h:592
 check_cpu_stall kernel/rcu/tree_stall.h:745 [inline]
 rcu_pending kernel/rcu/tree.c:3936 [inline]
 rcu_sched_clock_irq+0x843/0x1120 kernel/rcu/tree.c:2619
 update_process_times+0x193/0x200 kernel/time/timer.c:2021
 tick_sched_handle kernel/time/tick-sched.c:254 [inline]
 tick_sched_timer+0x37d/0x560 kernel/time/tick-sched.c:1473
 __run_hrtimer kernel/time/hrtimer.c:1685 [inline]
 __hrtimer_run_queues+0x4b4/0xb70 kernel/time/hrtimer.c:1749
 hrtimer_interrupt+0x3bb/0x8d0 kernel/time/hrtimer.c:1811
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1097 [inline]
 __sysvec_apic_timer_interrupt+0x137/0x4a0 arch/x86/kernel/apic/apic.c:1114
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0x4d/0xc0 arch/x86/kernel/apic/apic.c:1108
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
RIP: 0010:arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
RIP: 0010:kvm_wait+0x159/0x1b0 arch/x86/kernel/kvm.c:918
Code: 89 df 48 89 f8 48 c1 e8 03 42 0f b6 04 30 84 c0 75 4b 0f b6 1f e8 77 b8 4a 00 44 38 e3 75 10 66 90 0f 00 2d f9 db f3 08 fb f4 <e9> 16 ff ff ff fb e9 10 ff ff ff e8 27 20 88 08 89 f9 80 e1 07 38
RSP: 0000:ffffc90000dd08c0 EFLAGS: 00000246
RAX: 30f4cf225185ae00 RBX: 0000000000000003 RCX: 30f4cf225185ae00
RDX: dffffc0000000000 RSI: ffffffff8a2b3100 RDI: ffffffff8a7a0700
RBP: ffffc90000dd0970 R08: ffffffff901d615f R09: 1ffffffff203ac2b
R10: dffffc0000000000 R11: fffffbfff203ac2c R12: 0000000000000003
R13: ffff8880b913b154 R14: dffffc0000000000 R15: 1ffff920001ba118
 pv_wait arch/x86/include/asm/paravirt.h:597 [inline]
 pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:470 [inline]
 __pv_queued_spin_lock_slowpath+0x60f/0x9c0 kernel/locking/qspinlock.c:508
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:585 [inline]
 queued_spin_lock_slowpath+0x43/0x50 arch/x86/include/asm/qspinlock.h:51
 queued_spin_lock include/asm-generic/qspinlock.h:85 [inline]
 do_raw_spin_lock+0x265/0x2f0 kernel/locking/spinlock_debug.c:115
 spin_lock include/linux/spinlock.h:364 [inline]
 tcp_write_timer+0x29/0x280 net/ipv4/tcp_timer.c:673
 call_timer_fn+0x17b/0x540 kernel/time/timer.c:1648
 expire_timers kernel/time/timer.c:1699 [inline]
 __run_timers+0x53e/0x800 kernel/time/timer.c:1970
 run_timer_softirq+0x63/0xf0 kernel/time/timer.c:1983
 handle_softirqs+0x339/0x830 kernel/softirq.c:576
 __do_softirq kernel/softirq.c:610 [inline]
 invoke_softirq kernel/softirq.c:450 [inline]
 __irq_exit_rcu+0x13b/0x230 kernel/softirq.c:659
 irq_exit_rcu+0x5/0x20 kernel/softirq.c:671
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1108 [inline]
 sysvec_apic_timer_interrupt+0xa0/0xc0 arch/x86/kernel/apic/apic.c:1108
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676
RIP: 0010:charge_memcg+0x25a/0x2f0 mm/memcontrol.c:6777
Code: ff 49 8b 86 90 10 00 00 65 4c 01 b8 10 09 00 00 4c 89 f7 48 89 de e8 b5 17 00 00 e8 e0 30 bc ff fb 48 c7 44 24 20 0e 36 e0 45 <48> 8b 44 24 18 4a c7 04 28 00 00 00 00 65 48 8b 04 25 28 00 00 00
RSP: 0000:ffffc9000315fa60 EFLAGS: 00000286
RAX: 30f4cf225185ae00 RBX: ffffea0001597300 RCX: 30f4cf225185ae00
RDX: dffffc0000000000 RSI: ffffffff8a2b3100 RDI: ffffffff8a7a0700
RBP: ffffc9000315fb10 R08: ffffffff901d60f7 R09: 1ffffffff203ac1e
R10: dffffc0000000000 R11: fffffbfff203ac1f R12: 0000000000000000
R13: dffffc0000000000 R14: ffff888016e7c000 R15: 0000000000000001
 __mem_cgroup_charge+0x21/0x80 mm/memcontrol.c:6801
 mem_cgroup_charge include/linux/memcontrol.h:700 [inline]
 wp_page_copy+0x4ce/0x2050 mm/memory.c:3078
 handle_pte_fault mm/memory.c:4668 [inline]
 __handle_mm_fault mm/memory.c:4785 [inline]
 handle_mm_fault+0x1f06/0x4410 mm/memory.c:4883
 do_user_addr_fault+0x489/0xc80 arch/x86/mm/fault.c:1355
 handle_page_fault arch/x86/mm/fault.c:1443 [inline]
 exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1496
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0033:0x7f003cd42b3a
Code: 83 f9 1f 0f 86 1b 01 00 00 48 8b 45 70 66 49 0f 6e e7 49 8d 54 1d 00 66 48 0f 6e c0 66 0f 6c c4 4c 39 78 18 0f 85 bc 01 00 00 <0f> 11 42 10 48 89 55 70 48 89 50 18 48 81 fb ff 03 00 00 77 04 48
RSP: 002b:00007ffd0394dcd0 EFLAGS: 00010246
RAX: 00007f003ce7bb20 RBX: 0000000000001010 RCX: 00000000000008b0
RDX: 00005640d7c9de10 RSI: 00007f003ce7c180 RDI: 00005640d7c9ce00
RBP: 00007f003ce7bac0 R08: 00007f003ce7bac0 R09: 0000000000000000
R10: 0000000000000003 R11: 0000000000000001 R12: 0000000000001000
R13: 00005640d7c9ce00 R14: 00000000000018c0 R15: 00007f003ce7bb20
 </TASK>