rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...0: (1 GPs behind) idle=ddac/1/0x4000000000000000 softirq=30013/30013 fqs=1079
rcu: hardirqs softirqs csw/system
rcu: number: 0 0 0
rcu: cputime: 0 0 0 ==> 52500(ms)
rcu: (detected by 1, t=10505 jiffies, g=29777, q=732 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 9054 Comm: syz.1.1167 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:llist_empty include/linux/llist.h:218 [inline]
RIP: 0010:__netif_schedule+0x29/0x70 net/core/dev.c:3401
Code: 90 f3 0f 1e fa 53 48 89 fb e8 d3 2c 9c f8 48 8d bb 08 02 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 <75> 2f 48 8b 83 08 02 00 00 48 85 c0 74 0b e8 a4 2c 9c f8 5b c3 cc
RSP: 0018:ffffc90000007dd8 EFLAGS: 00000046
RAX: dffffc0000000000 RBX: ffff88807733a000 RCX: ffffffff89a9d7c2
RDX: 1ffff1100ee67441 RSI: ffffffff896d528d RDI: ffff88807733a208
RBP: ffff88805337e400 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
R13: 18bc194cca82f5b2 R14: ffff88805306d000 R15: ffff88805306d000
FS: 00007f55f8aba6c0(0000) GS:ffff8881242ec000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c32a29c CR3: 000000007d1a6000 CR4: 00000000003526f0
Call Trace:
advance_sched+0x740/0xd20 net/sched/sch_taprio.c:993
__run_hrtimer kernel/time/hrtimer.c:2032 [inline]
__hrtimer_run_queues+0x462/0x9c0 kernel/time/hrtimer.c:2096
hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2215
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline]
__sysvec_apic_timer_interrupt+0x109/0x470 arch/x86/kernel/apic/apic.c:1068
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1062
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
RIP: 0010:percpu_down_read_internal include/linux/percpu-rwsem.h:64 [inline]
RIP: 0010:percpu_down_read include/linux/percpu-rwsem.h:77 [inline]
RIP: 0010:cpus_read_lock+0x6c/0x170 kernel/cpu.c:490
Code: bf 01 00 00 00 e8 b4 50 0e 00 e8 cf ac d4 09 31 ff 89 c3 89 c6 e8 64 f4 42 00 58 85 db 75 5d e8 ea f9 42 00 8b 1d a4 fb a0 0c <31> ff 89 de e8 4b f4 42 00 85 db 0f 85 bd 00 00 00 e8 ce f9 42 00
RSP: 0018:ffffc90003317c90 EFLAGS: 00000287
RAX: 00000000000000ca RBX: 0000000000000000 RCX: ffffc90003f09000
RDX: 0000000000080000 RSI: ffffffff81c68576 RDI: ffff888068f84a80
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 1ffff92000662fb6
R13: 1ffff92000662f9f R14: 000000000cf97544 R15: 0000000000000000
class_cpus_read_lock_constructor include/linux/cpuhplock.h:49 [inline]
clock_was_set+0x96/0x850 kernel/time/hrtimer.c:988
do_settimeofday64+0x330/0x4d0 kernel/time/timekeeping.c:1684
do_sys_settimeofday64+0x1dc/0x260 kernel/time/time.c:195
__do_sys_clock_settime kernel/time/posix-timers.c:1139 [inline]
__se_sys_clock_settime kernel/time/posix-timers.c:1123 [inline]
__x64_sys_clock_settime+0x1c1/0x2a0 kernel/time/posix-timers.c:1123
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f55f7b9ce59
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:00007f55f8aba028 EFLAGS: 00000246 ORIG_RAX: 00000000000000e3
RAX: ffffffffffffffda RBX: 00007f55f7e15fa0 RCX: 00007f55f7b9ce59
RDX: 0000000000000000 RSI: 0000200000000240 RDI: 0000000000000000
RBP: 00007f55f7c32e6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f55f7e16038 R14: 00007f55f7e15fa0 R15: 00007ffc6e05a658
rcu: rcu_preempt kthread starved for 5110 jiffies! g29777 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:27416 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5504 [inline]
__schedule+0x125c/0x6730 kernel/sched/core.c:7228
__schedule_loop kernel/sched/core.c:7307 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:7322
schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2123
rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2325
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 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: 595 Comm: kworker/u8:7 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
Workqueue: writeback wb_workfn (flush-8:0)
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0x589/0x16c0 kernel/smp.c:892
Code: b8 00 00 00 00 00 fc ff df 48 8b 54 24 08 49 89 d5 49 89 d4 49 c1 ed 03 41 83 e4 07 49 01 c5 41 83 c4 03 e8 b9 95 0c 00 f3 90 <41> 0f b6 45 00 41 38 c4 7c 08 84 c0 0f 85 2c 0f 00 00 8b 45 08 31
RSP: 0018:ffffc90003f06820 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff81fce9cd
RDX: ffff888026d0ca80 RSI: ffffffff81fce9a7 RDI: ffff888026d0ca80
RBP: ffff8880b8443680 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003
R13: ffffed10170886d1 R14: 0000000000000001 R15: ffff8880b853c880
FS: 0000000000000000(0000) GS:ffff8881243ec000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f3163e95910 CR3: 00000000739dc000 CR4: 00000000003526f0
Call Trace:
on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1057
__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+0x45f/0x16f0 arch/x86/mm/tlb.c:1451
flush_tlb_page arch/x86/include/asm/tlbflush.h:345 [inline]
ptep_clear_flush+0x148/0x170 mm/pgtable-generic.c:104
page_vma_mkclean_one.constprop.0+0x3a2/0x7b0 mm/rmap.c:1138
page_mkclean_one+0x1cd/0x2b0 mm/rmap.c:1186
__rmap_walk_file+0x383/0x680 mm/rmap.c:3064
rmap_walk_file+0x1d8/0x2a0 mm/rmap.c:3097
rmap_walk mm/rmap.c:3108 [inline]
folio_mkclean+0x2af/0x4e0 mm/rmap.c:1218
folio_clear_dirty_for_io+0x1ba/0x960 mm/page-writeback.c:2909
mpage_submit_folio+0x84/0x330 fs/ext4/inode.c:2085
mpage_process_page_bufs+0x473/0x8d0 fs/ext4/inode.c:2215
mpage_prepare_extent_to_map+0xb50/0x1920 fs/ext4/inode.c:2754
ext4_do_writepages+0x9f9/0x3ed0 fs/ext4/inode.c:2895
ext4_writepages+0x347/0x750 fs/ext4/inode.c:3043
do_writepages+0x278/0x600 mm/page-writeback.c:2571
__writeback_single_inode+0x164/0x1300 fs/fs-writeback.c:1787
writeback_sb_inodes+0x766/0x1c50 fs/fs-writeback.c:2079
__writeback_inodes_wb+0xf8/0x2d0 fs/fs-writeback.c:2155
wb_writeback+0x6f6/0xb50 fs/fs-writeback.c:2266
wb_check_old_data_flush fs/fs-writeback.c:2370 [inline]
wb_do_writeback fs/fs-writeback.c:2449 [inline]
wb_workfn+0x93f/0xc80 fs/fs-writeback.c:2477
process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
process_scheduled_works kernel/workqueue.c:3405 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245