rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 1-...!: (1 GPs behind) idle=c2f4/1/0x4000000000000000 softirq=88579/88579 fqs=186
rcu: (detected by 0, t=10502 jiffies, g=105613, q=223 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 5613 Comm: syz-executor 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:lockdep_enabled kernel/locking/lockdep.c:124 [inline]
RIP: 0010:lock_is_held_type+0x42/0x140 kernel/locking/lockdep.c:5933
Code: 8b 15 aa 46 80 08 85 d2 0f 85 de 00 00 00 41 57 41 56 41 55 41 54 55 53 48 83 ec 08 65 48 8b 2d 1c ff 7f 08 8b 95 8c 0b 00 00 <85> d2 0f 85 a7 00 00 00 48 89 fb 41 89 f4 9c 41 5d fa 48 c7 c7 43
RSP: 0018:ffffc90000a08d98 EFLAGS: 00000092
RAX: 00000000ffffffff RBX: ffff888038d07300 RCX: 0000000000000001
RDX: 0000000000000000 RSI: 00000000ffffffff RDI: ffff888038d072c0
RBP: ffff88807b4e8000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000001
R13: ffff88807b4e8b78 R14: dffffc0000000000 R15: ffff8880b8528750
FS: 000055557353c500(0000) GS:ffff888124487000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f870c414a10 CR3: 000000005c3d8000 CR4: 00000000003526f0
Call Trace:
lock_is_held include/linux/lockdep.h:249 [inline]
advance_sched+0x7a4/0xd20 net/sched/sch_taprio.c:935
__run_hrtimer kernel/time/hrtimer.c:1930 [inline]
__hrtimer_run_queues+0x470/0xa00 kernel/time/hrtimer.c:1994
hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2113
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
__sysvec_apic_timer_interrupt+0x10b/0x460 arch/x86/kernel/apic/apic.c:1067
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1061
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:finish_task_switch.isra.0+0x2d3/0x1010 kernel/sched/core.c:5245
Code: 2f 0a 00 00 41 c7 87 e0 0d 00 00 00 00 00 00 e9 0f 04 00 00 49 8d 7f 48 e8 ea 2a b7 09 e8 c5 9e 3b 00 fb 48 8d bb c8 16 00 00 <48> b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 0f b6 04 02 84
RSP: 0018:ffffc90003e47a58 EFLAGS: 00000202
RAX: 00000000007e2643 RBX: ffff88807b4e8000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8df0fe0d RDI: ffff88807b4e96c8
RBP: ffffc90003e47ab0 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff888037b12540
R13: 0000000000000001 R14: ffffffff90d74ce4 R15: ffff8880b853b480
context_switch kernel/sched/core.c:5391 [inline]
__schedule+0x129d/0x67a0 kernel/sched/core.c:7189
__schedule_loop kernel/sched/core.c:7268 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:7283
do_nanosleep+0x158/0x570 kernel/time/hrtimer.c:2293
hrtimer_nanosleep+0x14f/0x350 kernel/time/hrtimer.c:2339
common_nsleep+0xa1/0xd0 kernel/time/posix-timers.c:1345
__do_sys_clock_nanosleep kernel/time/posix-timers.c:1391 [inline]
__se_sys_clock_nanosleep kernel/time/posix-timers.c:1368 [inline]
__x64_sys_clock_nanosleep+0x336/0x480 kernel/time/posix-timers.c:1368
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: 0033:0x7f5d9b35d68e
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007fff19893178 EFLAGS: 00000246 ORIG_RAX: 00000000000000e6
RAX: ffffffffffffffda RBX: 000055557353c500 RCX: 00007f5d9b35d68e
RDX: 00007fff198931d0 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007fff1989323c R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000001388
R13: 00000000000927c0 R14: 000000000010b085 R15: 00007fff19893290
rcu: rcu_preempt kthread starved for 10130 jiffies! g105613 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:27752 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x1295/0x67a0 kernel/sched/core.c:7189
__schedule_loop kernel/sched/core.c:7268 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:7283
schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095
rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297
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: 0 UID: 0 PID: 1037 Comm: kworker/u8:6 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:__sanitizer_cov_trace_const_cmp4+0x8/0x20 kernel/kcov.c:314
Code: bf 03 00 00 00 e9 58 fe ff ff 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 0c 24 <89> f2 89 fe bf 05 00 00 00 e9 2a fe ff ff 66 2e 0f 1f 84 00 00 00
RSP: 0018:ffffc90005566810 EFLAGS: 00000202
RAX: 0000000000000001 RBX: 0000000000000001 RCX: ffffffff81fc2dfd
RDX: ffff888028ee2540 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffff8880b8541180 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003
R13: ffffed10170a8231 R14: 0000000000000001 R15: ffff8880b843c800
FS: 0000000000000000(0000) GS:ffff888124387000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9d3a3d5d58 CR3: 0000000027b62000 CR4: 00000000003526f0
Call Trace:
csd_lock_wait kernel/smp.c:342 [inline]
smp_call_function_many_cond+0x5ad/0x1700 kernel/smp.c:892
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/0x810 mm/page-writeback.c:2905
mpage_submit_folio+0x84/0x330 fs/ext4/inode.c:2084
mpage_process_page_bufs+0x473/0x8d0 fs/ext4/inode.c:2214
mpage_prepare_extent_to_map+0xb50/0x1920 fs/ext4/inode.c:2753
ext4_do_writepages+0x9fe/0x3f20 fs/ext4/inode.c:2894
ext4_writepages+0x347/0x790 fs/ext4/inode.c:3042
do_writepages+0x278/0x600 mm/page-writeback.c:2571
__writeback_single_inode+0x164/0x1350 fs/fs-writeback.c:1764
writeback_sb_inodes+0x766/0x1c60 fs/fs-writeback.c:2056
__writeback_inodes_wb+0xf8/0x2d0 fs/fs-writeback.c:2132
wb_writeback+0x720/0xb90 fs/fs-writeback.c:2243
wb_check_old_data_flush fs/fs-writeback.c:2347 [inline]
wb_do_writeback fs/fs-writeback.c:2400 [inline]
wb_workfn+0x8dd/0xc00 fs/fs-writeback.c:2428
process_one_work+0xa0e/0x1980 kernel/workqueue.c:3314
process_scheduled_works kernel/workqueue.c:3397 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3478
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