rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 1-...!: (1 GPs behind) idle=9a2c/1/0x4000000000000000 softirq=182963/182975 fqs=15
rcu: (detected by 0, t=10505 jiffies, g=173017, q=246 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 2925 Comm: syz.5.6504 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:26 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:109 [inline]
RIP: 0010:arch_irqs_disabled arch/x86/include/asm/irqflags.h:151 [inline]
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x2b/0x80 kernel/locking/spinlock.c:194
Code: 0f 1e fa 55 48 89 f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 b6 1b 1f f6 48 89 df e8 6e 6e 1f f6 f7 c5 00 02 00 00 75 23 9c <58> f6 c4 02 75 37 bf 01 00 00 00 e8 75 71 0f f6 65 8b 05 2e c9 37
RSP: 0018:ffffc90000a08d00 EFLAGS: 00000046
RAX: 0000000000000001 RBX: ffffffff9ae307c0 RCX: ffffffff819a45a3
RDX: dffffc0000000000 RSI: 0000000000000004 RDI: ffffffff9ae307c0
RBP: 0000000000000006 R08: 0000000000000000 R09: fffffbfff35c60f8
R10: ffffffff9ae307c3 R11: ffffffff9ae307c0 R12: 0000000000000002
R13: ffff888025360300 R14: dffffc0000000000 R15: 1ffff920001411a8
FS: 0000000000000000(0000) GS:ffff8881249f6000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f38ecf733e0 CR3: 00000000518a0000 CR4: 00000000003526f0
Call Trace:
debug_object_activate+0x2ec/0x4c0 lib/debugobjects.c:836
debug_hrtimer_activate kernel/time/hrtimer.c:438 [inline]
debug_activate kernel/time/hrtimer.c:477 [inline]
enqueue_hrtimer+0x23/0x380 kernel/time/hrtimer.c:1081
__run_hrtimer kernel/time/hrtimer.c:1794 [inline]
__hrtimer_run_queues+0xa31/0xc40 kernel/time/hrtimer.c:1841
hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1903
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline]
__sysvec_apic_timer_interrupt+0x10b/0x3c0 arch/x86/kernel/apic/apic.c:1062
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1056
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:get_current arch/x86/include/asm/current.h:25 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x8/0x70 kernel/kcov.c:216
Code: e9 cd 16 5e 00 be 03 00 00 00 5b e9 e2 d9 ed 02 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 34 24 <65> 48 8b 15 08 bc f3 11 65 8b 05 19 bc f3 11 a9 00 01 ff 00 74 1d
RSP: 0018:ffffc9000c787358 EFLAGS: 00000297
RAX: 0000000000000000 RBX: 0000000000000003 RCX: ffffffff81b2825a
RDX: ffff888029eac980 RSI: ffffffff81b28269 RDI: 0000000000000005
RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000007
R10: 0000000000000001 R11: ffff888029ead4b0 R12: 1ffffffff21115da
R13: 0000000000000001 R14: ffff8880b853bf00 R15: 0000000000000002
___clear_bit include/asm-generic/bitops/instrumented-non-atomic.h:44 [inline]
__cpumask_clear_cpu include/linux/cpumask.h:636 [inline]
smp_call_function_many_cond+0x719/0x15e0 kernel/smp.c:815
on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1043
__flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline]
flush_tlb_multi arch/x86/mm/tlb.c:1382 [inline]
flush_tlb_mm_range+0x2f0/0x12c0 arch/x86/mm/tlb.c:1472
tlb_flush arch/x86/include/asm/tlb.h:23 [inline]
tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:490 [inline]
tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:480 [inline]
zap_pte_range mm/memory.c:1881 [inline]
zap_pmd_range mm/memory.c:1946 [inline]
zap_pud_range mm/memory.c:1975 [inline]
zap_p4d_range mm/memory.c:1996 [inline]
unmap_page_range+0x1fd3/0x43c0 mm/memory.c:2017
unmap_single_vma+0x153/0x240 mm/memory.c:2059
unmap_vmas+0x218/0x470 mm/memory.c:2101
exit_mmap+0x1b0/0xb60 mm/mmap.c:1277
__mmput+0x12a/0x410 kernel/fork.c:1173
mmput+0x62/0x70 kernel/fork.c:1196
exit_mm kernel/exit.c:581 [inline]
do_exit+0x7d7/0x2bd0 kernel/exit.c:959
do_group_exit+0xd3/0x2a0 kernel/exit.c:1112
get_signal+0x2671/0x26d0 kernel/signal.c:3034
arch_do_signal_or_restart+0x8f/0x7e0 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
exit_to_user_mode_loop+0x8c/0x540 kernel/entry/common.c:75
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
do_syscall_64+0x4ee/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f38ecf8f749
Code: Unable to access opcode bytes at 0x7f38ecf8f71f.
RSP: 002b:00007f38ede54038 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: 000000000000000b RBX: 00007f38ed1e6090 RCX: 00007f38ecf8f749
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00002000000002c0
RBP: 00007f38ed013f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f38ed1e6128 R14: 00007f38ed1e6090 R15: 00007ffd07c56f78
rcu: rcu_preempt kthread starved for 10430 jiffies! g173017 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:27952 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x1139/0x6150 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:6960
schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083
rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 11638 Comm: kworker/u8:31 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: writeback wb_workfn (flush-8:0)
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82
Code: c6 5f 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 13 59 12 00 fb f4 cc 35 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffc90002ed66d0 EFLAGS: 000002d3
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000000006
RDX: ffff88801fee4980 RSI: ffffffff816bdc71 RDI: ffffffff8bf2b300
RBP: ffff88803661dcc0 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff9088aed7 R11: ffff88801fee54b0 R12: 0000000000000003
R13: 0000000000000003 R14: ffff8880b843bbc0 R15: ffffed1006cc3b98
FS: 0000000000000000(0000) GS:ffff8881248f6000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe404610ca0 CR3: 00000000314ec000 CR4: 00000000003526f0
Call Trace:
arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
kvm_wait arch/x86/kernel/kvm.c:1085 [inline]
kvm_wait+0x186/0x1f0 arch/x86/kernel/kvm.c:1067
pv_wait arch/x86/include/asm/paravirt.h:569 [inline]
pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:466 [inline]
__pv_queued_spin_lock_slowpath+0x4e1/0xcf0 kernel/locking/qspinlock.c:325
pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:557 [inline]
queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline]
queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
do_raw_spin_lock+0x20e/0x2b0 kernel/locking/spinlock_debug.c:116
spin_lock include/linux/spinlock.h:351 [inline]
__pte_offset_map_lock+0x10f/0x310 mm/pgtable-generic.c:403
pte_offset_map_lock include/linux/mm.h:3361 [inline]
map_pte mm/page_vma_mapped.c:24 [inline]
page_vma_mapped_walk+0x1ece/0x32b0 mm/page_vma_mapped.c:295
page_vma_mkclean_one.constprop.0+0x2f4/0x820 mm/rmap.c:997
page_mkclean_one+0x196/0x260 mm/rmap.c:1065
__rmap_walk_file+0x359/0x620 mm/rmap.c:2927
rmap_walk_file+0x174/0x1f0 mm/rmap.c:2960
rmap_walk mm/rmap.c:2971 [inline]
folio_mkclean+0x251/0x3f0 mm/rmap.c:1097
folio_clear_dirty_for_io+0x153/0x6b0 mm/page-writeback.c:2932
mpage_submit_folio+0x84/0x2d0 fs/ext4/inode.c:2068
mpage_process_page_bufs+0x47c/0x8d0 fs/ext4/inode.c:2198
mpage_prepare_extent_to_map+0x750/0x1510 fs/ext4/inode.c:2737
ext4_do_writepages+0xa11/0x3c80 fs/ext4/inode.c:2878
ext4_writepages+0x37a/0x7d0 fs/ext4/inode.c:3026
do_writepages+0x27a/0x600 mm/page-writeback.c:2598
__writeback_single_inode+0x168/0x14a0 fs/fs-writeback.c:1737
writeback_sb_inodes+0x72e/0x1ce0 fs/fs-writeback.c:2030
__writeback_inodes_wb+0xf8/0x2d0 fs/fs-writeback.c:2107
wb_writeback+0x799/0xae0 fs/fs-writeback.c:2218
wb_check_old_data_flush fs/fs-writeback.c:2322 [inline]
wb_do_writeback fs/fs-writeback.c:2375 [inline]
wb_workfn+0x8a0/0xbb0 fs/fs-writeback.c:2403
process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257
process_scheduled_works kernel/workqueue.c:3340 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421
kthread+0x3c5/0x780 kernel/kthread.c:463
ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246