rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6771/1:b..l
rcu: (detected by 0, t=10502 jiffies, g=15169, q=1347 ncpus=2)
task:syz.0.374 state:R running task stack:25320 pid:6771 tgid:6770 ppid:5844 task_flags:0x40054c flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5392 [inline]
__schedule+0x16f5/0x4d00 kernel/sched/core.c:6781
preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:6961
preempt_schedule+0xae/0xc0 kernel/sched/core.c:6985
preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
__raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
_raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:391 [inline]
zap_pte_range mm/memory.c:1761 [inline]
zap_pmd_range mm/memory.c:1823 [inline]
zap_pud_range mm/memory.c:1852 [inline]
zap_p4d_range mm/memory.c:1873 [inline]
unmap_page_range+0x38e8/0x4580 mm/memory.c:1894
unmap_vmas+0x25d/0x3c0 mm/memory.c:1984
exit_mmap+0x245/0xba0 mm/mmap.c:1284
__mmput+0x118/0x420 kernel/fork.c:1381
exit_mm+0x1da/0x2c0 kernel/exit.c:595
do_exit+0x864/0x2550 kernel/exit.c:947
do_group_exit+0x21c/0x2d0 kernel/exit.c:1108
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:111
exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline]
do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa2fe78e969
RSP: 002b:00007fa2ff6bc0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00007fa2fe9b5fa8 RCX: 00007fa2fe78e969
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fa2fe9b5fa8
RBP: 00007fa2fe9b5fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fa2fe9b5fac
R13: 0000000000000000 R14: 00007fff41b60760 R15: 00007fff41b60848
rcu: rcu_preempt kthread starved for 4994 jiffies! g15169 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:27128 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5392 [inline]
__schedule+0x16f5/0x4d00 kernel/sched/core.c:6781
__schedule_loop kernel/sched/core.c:6859 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6874
schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2054
rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2256
kthread+0x70e/0x8a0 kernel/kthread.c:464
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: 0 UID: 0 PID: 5572 Comm: crond Not tainted 6.15.0-syzkaller-07787-g27eab4c64423 #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:queued_write_lock_slowpath+0x125/0x260 kernel/locking/qrwlock.c:85
Code: 00 01 00 00 43 0f b6 04 27 84 c0 74 35 89 d9 80 e1 07 80 c1 03 38 c1 7c 29 48 89 df e8 14 d5 bc f6 eb 1f f3 90 43 0f b6 04 27 <84> c0 74 14 89 d9 80 e1 07 80 c1 03 38 c1 7c 08 48 89 df e8 f3 d4
RSP: 0018:ffffc900000074e0 EFLAGS: 00000206
RAX: 0000000000000000 RBX: ffffffff8f61c5e0 RCX: ffffffff8b664328
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffffff8f61c5e0
RBP: ffffc90000007590 R08: ffffffff8f61c5e3 R09: 1ffffffff1ec38bc
R10: dffffc0000000000 R11: fffffbfff1ec38bd R12: dffffc0000000000
R13: 1ffff92000000ea0 R14: ffffc90000007530 R15: 1ffffffff1ec38bc
FS: 0000000000000000(0000) GS:ffff888125c66000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c39600b CR3: 000000000df36000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
queued_write_lock include/asm-generic/qrwlock.h:101 [inline]
do_raw_write_lock+0x1f2/0x260 kernel/locking/spinlock_debug.c:211
___neigh_create+0xe81/0x2260 net/core/neighbour.c:641
ip6_finish_output2+0xb4d/0x16a0 net/ipv6/ip6_output.c:132
__ip6_finish_output net/ipv6/ip6_output.c:-1 [inline]
ip6_finish_output+0x234/0x7d0 net/ipv6/ip6_output.c:226
NF_HOOK include/linux/netfilter.h:317 [inline]
ndisc_send_skb+0xb47/0x1400 net/ipv6/ndisc.c:513
addrconf_rs_timer+0x369/0x670 net/ipv6/addrconf.c:4041
call_timer_fn+0x17e/0x5f0 kernel/time/timer.c:1747
expire_timers kernel/time/timer.c:1798 [inline]
__run_timers kernel/time/timer.c:2372 [inline]
__run_timer_base+0x61a/0x860 kernel/time/timer.c:2384
run_timer_base kernel/time/timer.c:2393 [inline]
run_timer_softirq+0xb7/0x180 kernel/time/timer.c:2403
handle_softirqs+0x286/0x870 kernel/softirq.c:579
__do_softirq kernel/softirq.c:613 [inline]
invoke_softirq kernel/softirq.c:453 [inline]
__irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680
irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1050
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline]
RIP: 0010:smp_call_function_many_cond+0xe69/0x11c0 kernel/smp.c:885
Code: 00 45 8b 2f 44 89 ee 83 e6 01 31 ff e8 b0 77 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 5b 73 0b 00 eb 37 f3 90 <43> 0f b6 04 2c 84 c0 75 10 41 f7 07 01 00 00 00 74 1e e8 40 73 0b
RSP: 0018:ffffc90003faf360 EFLAGS: 00000293
RAX: ffffffff81b487b0 RBX: ffff8880b863cc00 RCX: ffff88801fbb0000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90003faf4c0 R08: ffffffff8fa0b1b7 R09: 1ffffffff1f41636
R10: dffffc0000000000 R11: fffffbfff1f41637 R12: 1ffff110170e8271
R13: dffffc0000000000 R14: 0000000000000001 R15: ffff8880b8741388
on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1052
__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+0x6b1/0x12c0 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:480 [inline]
tlb_flush_mmu+0x1a7/0x680 mm/mmu_gather.c:403
tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:496
free_ldt_pgtables+0x17b/0x320 arch/x86/kernel/ldt.c:411
arch_exit_mmap arch/x86/include/asm/mmu_context.h:234 [inline]
exit_mmap+0x179/0xba0 mm/mmap.c:1270
__mmput+0x118/0x420 kernel/fork.c:1381
exit_mm+0x1da/0x2c0 kernel/exit.c:595
do_exit+0x864/0x2550 kernel/exit.c:947
do_group_exit+0x21c/0x2d0 kernel/exit.c:1108
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:111
exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline]
do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe49ee6eb0a
Code: Unable to access opcode bytes at 0x7fe49ee6eae0.
RSP: 002b:00007ffd7ed31468 EFLAGS: 00000246 ORIG_RAX: 0000000000000106
RAX: 0000000000000000 RBX: 00007fe49f01e490 RCX: 00007fe49ee6eb0a
RDX: 00007ffd7ed31488 RSI: 00007fe49eff77e8 RDI: 00000000ffffff9c
RBP: 0000000068398dd0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000003c R14: 0000000000000000 R15: 000000000000003c