rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (1 ticks this GP) idle=52ec/1/0x4000000000000000 softirq=71620/71620 fqs=6
rcu: (detected by 1, t=10502 jiffies, g=46085, q=214 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 13108 Comm: syz.4.1282 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:arch_atomic_try_cmpxchg arch/x86/include/asm/atomic.h:107 [inline]
RIP: 0010:raw_atomic_try_cmpxchg_acquire include/linux/atomic/atomic-arch-fallback.h:2170 [inline]
RIP: 0010:atomic_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:1302 [inline]
RIP: 0010:queued_spin_lock include/asm-generic/qspinlock.h:111 [inline]
RIP: 0010:do_raw_spin_lock+0x121/0x290 kernel/locking/spinlock_debug.c:116
Code: 0f 84 f3 00 00 00 c7 44 24 40 00 00 00 00 48 89 df be 04 00 00 00 e8 4e 17 85 00 48 8d 7c 24 40 be 04 00 00 00 e8 3f 17 85 00 <8b> 44 24 40 b9 01 00 00 00 f0 0f b1 0b 0f 85 dd 00 00 00 65 8b 1d
RSP: 0018:ffffc90000007be0 EFLAGS: 00000097
RAX: 00000000ffffff01 RBX: ffff8880b8627a80 RCX: ffffffff819dffe1
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc90000007c20
RBP: ffffc90000007c90 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000000f84 R12: ffff8880b8627a90
R13: ffff8880b8627a88 R14: 1ffff110170c4f52 R15: 1ffff110170c4f51
FS: 0000000000000000(0000) GS:ffff888125c1b000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc554e5ef98 CR3: 000000005146a000 CR4: 0000000000350ef0
Call Trace:
__raw_spin_lock_irq include/linux/spinlock_api_smp.h:120 [inline]
_raw_spin_lock_irq+0xae/0xf0 kernel/locking/spinlock.c:170
__run_hrtimer kernel/time/hrtimer.c:1765 [inline]
__hrtimer_run_queues+0x602/0xc60 kernel/time/hrtimer.c:1825
hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline]
__sysvec_apic_timer_interrupt+0x10b/0x410 arch/x86/kernel/apic/apic.c:1056
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1050
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:folio_test_anon include/linux/page-flags.h:723 [inline]
RIP: 0010:__folio_rmap_sanity_checks+0x3cd/0x7d0 include/linux/rmap.h:467
Code: ad ff bf 00 00 04 00 89 ee e8 7f eb ad ff 81 fd 00 00 04 00 0f 85 81 01 00 00 e8 2e e7 ad ff 4c 8d 73 18 4c 89 f0 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 f7 e8 64 50 11 00 4d 8b 36 44 89 f6 83
RSP: 0018:ffffc90013f2f2d0 EFLAGS: 00000212
RAX: 1ffffd40003f3173 RBX: ffffea0001f98b80 RCX: ffff888030338000
RDX: 0000000000000000 RSI: ffffffff8e239720 RDI: 0000000000000000
RBP: 0000000000000001 R08: ffff888030338000 R09: 0000000000000003
R10: 0000000000000002 R11: 0000000000000000 R12: ffffea0001f98b80
R13: dffffc0000000000 R14: ffffea0001f98b98 R15: ffffea0001f98b80
__folio_remove_rmap mm/rmap.c:1694 [inline]
folio_remove_rmap_ptes+0x3b/0xaf0 mm/rmap.c:1804
zap_present_folio_ptes mm/memory.c:1523 [inline]
zap_present_ptes mm/memory.c:1581 [inline]
do_zap_pte_range mm/memory.c:1682 [inline]
zap_pte_range mm/memory.c:1726 [inline]
zap_pmd_range mm/memory.c:1818 [inline]
zap_pud_range mm/memory.c:1847 [inline]
zap_p4d_range mm/memory.c:1868 [inline]
unmap_page_range+0x1f7f/0x4370 mm/memory.c:1889
unmap_single_vma mm/memory.c:1932 [inline]
unmap_vmas+0x399/0x580 mm/memory.c:1976
exit_mmap+0x248/0xb50 mm/mmap.c:1280
__mmput+0x118/0x420 kernel/fork.c:1130
exit_mm+0x1da/0x2c0 kernel/exit.c:582
do_exit+0x648/0x2300 kernel/exit.c:949
do_group_exit+0x21c/0x2d0 kernel/exit.c:1102
get_signal+0x1286/0x1340 kernel/signal.c:3034
arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop+0x75/0x110 kernel/entry/common.c:40
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fec2518ebe9
Code: Unable to access opcode bytes at 0x7fec2518ebbf.
RSP: 002b:00007ffc97db1898 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffdfc RBX: 0000000000071fce RCX: 00007fec2518ebe9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fec253b5fac
RBP: 0000000000000fd2 R08: 7fffffffffffffff R09: 0000000197db1b8f
R10: 00007ffc97db1990 R11: 0000000000000246 R12: 00007fec253b5fac
R13: 00007ffc97db1990 R14: 0000000000072fa0 R15: 00007ffc97db19b0
rcu: rcu_preempt kthread starved for 10490 jiffies! g46085 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:27840 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7058
schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
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: 13128 Comm: syz.1.1287 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xd38/0x12d0 kernel/smp.c:877
Code: 89 ee 83 e6 01 31 ff e8 b6 62 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 61 5e 0b 00 eb 38 f3 90 42 0f b6 04 2b <84> c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 45 5e 0b 00 eb e4 44
RSP: 0018:ffffc90003a0f480 EFLAGS: 00000293
RAX: 0000000000000000 RBX: 1ffff110170c8341 RCX: ffff888079120000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90003a0f600 R08: ffffffff8fa38337 R09: 1ffffffff1f47066
R10: dffffc0000000000 R11: fffffbfff1f47067 R12: ffff8880b8641a08
R13: dffffc0000000000 R14: ffff8880b873b1c0 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888125d1b000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000010000 CR3: 00000000571c3000 CR4: 0000000000350ef0
Call Trace:
on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1044
__flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline]
flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline]
flush_tlb_mm_range+0x6b1/0x12d0 arch/x86/mm/tlb.c:1451
tlb_flush arch/x86/include/asm/tlb.h:23 [inline]
tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:490 [inline]
tlb_flush_mmu+0x1a7/0x680 mm/mmu_gather.c:403
tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:497
exit_mmap+0x44c/0xb50 mm/mmap.c:1293
__mmput+0x118/0x420 kernel/fork.c:1130
exit_mm+0x1da/0x2c0 kernel/exit.c:582
do_exit+0x648/0x2300 kernel/exit.c:949
do_group_exit+0x21c/0x2d0 kernel/exit.c:1102
get_signal+0x1286/0x1340 kernel/signal.c:3034
arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop+0x75/0x110 kernel/entry/common.c:40
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd06f98ebe9
Code: Unable to access opcode bytes at 0x7fd06f98ebbf.
RSP: 002b:00007fd070871038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: 0000000000000001 RBX: 00007fd06fbb5fa0 RCX: 00007fd06f98ebe9
RDX: 0000000004048043 RSI: 0000200000000800 RDI: 0000000000000003
RBP: 00007fd06fa11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd06fbb6038 R14: 00007fd06fbb5fa0 R15: 00007fffca110b38