rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=3424/1/0x4000000000000000 softirq=59065/59066 fqs=2 rcu: (detected by 1, t=10502 jiffies, g=69389, q=389 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 11565 Comm: syz.8.1544 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/10/2026 RIP: 0010:lockdep_recursion_inc kernel/locking/lockdep.c:465 [inline] RIP: 0010:lock_release+0x95/0x3c0 kernel/locking/lockdep.c:5888 Code: 0d 02 00 00 65 4c 8b 3d f1 5a ca 11 41 83 bf 9c 0b 00 00 00 0f 85 f7 01 00 00 49 81 3e 20 75 30 94 0f 84 ea 01 00 00 9c 5b fa <48> c7 c7 0b 5f 24 8e e8 df 2d 2d 0a 65 ff 05 a8 9f ca 11 c7 44 24 RSP: 0018:ffffc90000007ca8 EFLAGS: 00000006 RAX: 0000000000000000 RBX: 0000000000000006 RCX: 0000000080010002 RDX: 0000000000010000 RSI: ffffffff8c4bda60 RDI: ffffffff8c4bda20 RBP: 0000000000000001 R08: ffff88804fcd319f R09: 1ffff11009f9a633 R10: dffffc0000000000 R11: ffffed1009f9a634 R12: ffff888052067000 R13: ffffffff89dd1208 R14: ffffffff8eb59c60 R15: ffff8880459abe00 FS: 00007fb9cbeff6c0(0000) GS:ffff888124f55000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fb9cbeffd58 CR3: 0000000057e9a000 CR4: 0000000000350ef0 Call Trace: rcu_lock_release include/linux/rcupdate.h:310 [inline] rcu_read_unlock include/linux/rcupdate.h:871 [inline] advance_sched+0xb13/0xc80 net/sched/sch_taprio.c:994 __run_hrtimer kernel/time/hrtimer.c:2032 [inline] __hrtimer_run_queues+0x3bc/0xa10 kernel/time/hrtimer.c:2096 hrtimer_interrupt+0x448/0x910 kernel/time/hrtimer.c:2215 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline] __sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1068 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x47/0x80 kernel/locking/spinlock.c:198 Code: f7 e8 ad ac d0 f5 f7 c3 00 02 00 00 74 05 e8 a0 8e fc f5 9c 58 a9 00 02 00 00 75 27 f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 b4 c2 c1 f5 65 8b 05 ad 92 9a 07 85 c0 74 18 5b 41 5e e9 7c 23 RSP: 0018:ffffc90004c5fc08 EFLAGS: 00000206 RAX: 0000000000000002 RBX: 0000000000000246 RCX: 0000000080000001 RDX: 0000000000000007 RSI: ffffffff8e22b2e6 RDI: 0000000000000001 RBP: ffffc90004c5fd30 R08: ffffffff905783f7 R09: 1ffffffff20af07e R10: dffffc0000000000 R11: fffffbfff20af07f R12: 0000000000000008 R13: dffffc0000000000 R14: ffff8880b86281c0 R15: ffff8880b86281c0 class_raw_spinlock_irqsave_destructor include/linux/spinlock.h:573 [inline] clock_was_set+0x62b/0x7e0 kernel/time/hrtimer.c:997 do_settimeofday64+0x34e/0x590 kernel/time/timekeeping.c:1684 __do_sys_clock_settime kernel/time/posix-timers.c:1139 [inline] __se_sys_clock_settime kernel/time/posix-timers.c:1123 [inline] __x64_sys_clock_settime+0x253/0x2a0 kernel/time/posix-timers.c:1123 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fb9caf9de99 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fb9cbeff028 EFLAGS: 00000246 ORIG_RAX: 00000000000000e3 RAX: ffffffffffffffda RBX: 00007fb9cb226090 RCX: 00007fb9caf9de99 RDX: 0000000000000000 RSI: 0000200000000040 RDI: 0000000000000000 RBP: 00007fb9cb033eaf R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fb9cb226128 R14: 00007fb9cb226090 R15: 00007fffd8fca8f8 rcu: rcu_preempt kthread starved for 10498 jiffies! g69389 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:27560 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x17d9/0x56c0 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7326 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2325 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 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: 1 UID: 0 PID: 11556 Comm: syz.5.1543 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/10/2026 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0x10b5/0x14b0 kernel/smp.c:892 Code: 1e 89 de 83 e6 01 31 ff e8 d8 22 0c 00 83 e3 01 48 bb 00 00 00 00 00 fc ff df 75 07 e8 84 1e 0c 00 eb 37 f3 90 41 0f b6 04 1c <84> c0 75 10 41 f7 06 01 00 00 00 74 1e e8 69 1e 0c 00 eb e5 44 89 RSP: 0018:ffffc900057ff1a0 EFLAGS: 00000293 RAX: 0000000000000000 RBX: dffffc0000000000 RCX: ffff88807e7a1f00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc900057ff2c8 R08: ffff88807fe34bc7 R09: 1ffff1100ffc6978 R10: dffffc0000000000 R11: ffffffff8178e3f0 R12: 1ffff110170c85fd R13: ffff8880b873c448 R14: ffff8880b8642fe8 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888125055000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b34d14ff8 CR3: 0000000059acb000 CR4: 0000000000350ef0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 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+0x5c4/0x1090 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:509 [inline] zap_pte_range mm/memory.c:1961 [inline] zap_pmd_range mm/memory.c:2020 [inline] zap_pud_range mm/memory.c:2048 [inline] zap_p4d_range mm/memory.c:2069 [inline] __zap_vma_range+0x3ef5/0x4f10 mm/memory.c:2109 unmap_vmas+0x390/0x550 mm/memory.c:2178 exit_mmap+0x293/0x9f0 mm/mmap.c:1300 __mmput+0x118/0x420 kernel/fork.c:1187 exit_mm+0x221/0x2d0 kernel/exit.c:615 do_exit+0x6cd/0x2360 kernel/exit.c:997 do_group_exit+0x22d/0x2f0 kernel/exit.c:1152 get_signal+0x121b/0x12c0 kernel/signal.c:3046 arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0x104/0x730 kernel/entry/common.c:101 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline] do_syscall_64+0x353/0x580 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6076d9de99 Code: Unable to access opcode bytes at 0x7f6076d9de6f. RSP: 002b:00007f6077d2d028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: fffffffffffffe00 RBX: 00007f6077025fa0 RCX: 00007f6076d9de99 RDX: 0000000000000001 RSI: 0000200000000000 RDI: 0000000000000003 RBP: 00007f6076e33eaf R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f6077026038 R14: 00007f6077025fa0 R15: 00007ffeb6665dd8