rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=8acc/1/0x4000000000000000 softirq=96088/96092 fqs=0 rcu: (detected by 1, t=10502 jiffies, g=78169, q=96 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 14315 Comm: syz.8.1727 Not tainted 6.16.0-rc4-syzkaller-00108-g17bbde2e1716 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:separate_irq_context kernel/locking/lockdep.c:4706 [inline] RIP: 0010:__lock_acquire+0x73c/0xd20 kernel/locking/lockdep.c:5224 Code: 00 00 83 fb 31 0f 83 e0 05 00 00 48 8d 04 9b 45 8b 66 20 48 8b 4c 24 10 8b 44 c1 f8 44 31 e0 25 00 60 00 00 31 c9 89 c2 f7 da <48> 19 c9 49 09 cf 85 c0 b8 01 00 00 00 0f 45 e8 eb 4b 48 89 fb 4c RSP: 0018:ffffc90000007ad0 EFLAGS: 00000046 RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffff88802d5ee590 RDI: ffff88802d5eda00 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff84c7f1ea R10: dffffc0000000000 R11: fffff52000000f98 R12: 00000000000c4000 R13: 0000000000000002 R14: ffff88802d5ee590 R15: bc101d9a73125dae FS: 00007f2b0ebbc6c0(0000) GS:ffff888125c50000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b3191bff8 CR3: 0000000030041000 CR4: 0000000000350ef0 Call Trace: lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162 debug_object_deactivate+0x9a/0x250 lib/debugobjects.c:873 debug_hrtimer_deactivate kernel/time/hrtimer.c:450 [inline] debug_deactivate+0x1d/0x200 kernel/time/hrtimer.c:490 __run_hrtimer kernel/time/hrtimer.c:1729 [inline] __hrtimer_run_queues+0x2b0/0xc60 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:lock_acquire+0x175/0x360 kernel/locking/lockdep.c:5875 Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 0b dd fe 10 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e RSP: 0018:ffffc9000497f818 EFLAGS: 00000206 RAX: fd1c9f6c12f58200 RBX: 0000000000000000 RCX: fd1c9f6c12f58200 RDX: 0000000000000000 RSI: ffffffff8db6f1cc RDI: ffffffff8be28d00 RBP: ffffffff8210afae R08: 0000000000000000 R09: ffffffff8210afae R10: dffffc0000000000 R11: ffffed1005abdb41 R12: 0000000000000000 R13: ffff88807bede5b8 R14: 0000000000000001 R15: 0000000000000246 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] __pte_offset_map_lock+0x13e/0x210 mm/pgtable-generic.c:402 pte_offset_map_lock include/linux/mm.h:3010 [inline] follow_page_pte+0xc8/0x14b0 mm/gup.c:848 follow_pmd_mask mm/gup.c:971 [inline] follow_pud_mask mm/gup.c:1023 [inline] follow_p4d_mask mm/gup.c:1040 [inline] follow_page_mask mm/gup.c:1083 [inline] __get_user_pages+0xbad/0x30b0 mm/gup.c:1486 populate_vma_page_range+0x26b/0x340 mm/gup.c:1926 __mm_populate+0x24c/0x380 mm/gup.c:2029 mm_populate include/linux/mm.h:3348 [inline] vm_mmap_pgoff+0x3f0/0x4c0 mm/util.c:584 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f2b0dd8e929 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f2b0ebbc038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007f2b0dfb5fa0 RCX: 00007f2b0dd8e929 RDX: b635773f06ebbeee RSI: 0000000000b36000 RDI: 0000200000000000 RBP: 00007f2b0de10b39 R08: ffffffffffffffff R09: 0000000000000000 R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f2b0dfb5fa0 R15: 00007ffcb95746f8 rcu: rcu_preempt kthread starved for 10502 jiffies! g78169 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:27128 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x16f5/0x4d00 kernel/sched/core.c:6785 __schedule_loop kernel/sched/core.c:6863 [inline] schedule+0x165/0x360 kernel/sched/core.c:6878 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+0x711/0x8a0 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: 1 UID: 0 PID: 8949 Comm: syz-executor Not tainted 6.16.0-rc4-syzkaller-00108-g17bbde2e1716 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:smp_call_function_many_cond+0xf6e/0x12d0 kernel/smp.c:885 Code: 89 ee 83 e6 01 31 ff e8 c0 79 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 6b 75 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 50 75 0b 00 eb e5 44 89 RSP: 0000:ffffc9000abb7720 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff8880b873b1c0 RCX: ffff888027569e00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000abb7880 R08: ffffffff8fa10af7 R09: 1ffffffff1f4215e R10: dffffc0000000000 R11: fffffbfff1f4215f R12: 1ffff110170c8385 R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8880b8641c28 FS: 000055556f1ff500(0000) GS:ffff888125d50000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055556f21a5c8 CR3: 000000005fb24000 CR4: 0000000000350ef0 Call Trace: 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 flush_tlb_page arch/x86/include/asm/tlbflush.h:324 [inline] ptep_clear_flush+0x120/0x170 mm/pgtable-generic.c:101 wp_page_copy mm/memory.c:3635 [inline] do_wp_page+0x1bc2/0x5800 mm/memory.c:4030 handle_pte_fault mm/memory.c:6085 [inline] __handle_mm_fault+0x1144/0x5620 mm/memory.c:6212 handle_mm_fault+0x40a/0x8e0 mm/memory.c:6381 do_user_addr_fault+0xa81/0x1390 arch/x86/mm/fault.c:1336 handle_page_fault arch/x86/mm/fault.c:1476 [inline] exc_page_fault+0x76/0xf0 arch/x86/mm/fault.c:1532 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 RIP: 0033:0x7f586074cd9f Code: 8d 34 19 48 39 d5 48 89 75 60 0f 95 c2 48 29 d8 48 83 c1 10 0f b6 d2 48 83 c8 01 48 c1 e2 02 48 09 da 48 83 ca 01 48 89 51 f8 <48> 89 46 08 eb 80 48 8d 0d 01 d5 0e 00 48 8d 15 05 e7 0e 00 bf 01 RSP: 002b:00007ffcac0c5020 EFLAGS: 00010206 RAX: 0000000000018a41 RBX: 0000000000008040 RCX: 000055556f212590 RDX: 0000000000008041 RSI: 000055556f21a5c0 RDI: 0000000000000004 RBP: 00007f5860985ca0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000001000 R11: 0000000000000802 R12: 0000000000008030 R13: 0000000000000076 R14: 00007f5860985d00 R15: 0000000000000000