rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=33cc/1/0x4000000000000000 softirq=42983/42984 fqs=0 rcu: (detected by 0, t=10502 jiffies, g=46085, q=165 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 9829 Comm: syz.0.999 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:check_preemption_disabled+0x1c/0xe0 lib/smp_processor_id.c:54 Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 41 54 55 53 48 83 ec 08 65 8b 1d d5 25 aa 08 65 f7 05 c6 25 aa 08 ff ff ff 7f 74 0f <48> 83 c4 08 89 d8 5b 5d 41 5c c3 cc cc cc cc 9c 58 f6 c4 02 74 ea RSP: 0018:ffffc90000a08d68 EFLAGS: 00000002 RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffc90000a08d9c RDX: 0000000000000000 RSI: ffffffff8e17df68 RDI: ffffffff8c400f80 RBP: ffffffff89c71bf2 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff88807d67a540 R13: 18c1e43e528a5a29 R14: 0000000000000002 R15: 0000000000000001 FS: 00007f9c640556c0(0000) GS:ffff888123ee8000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9c64054ff8 CR3: 0000000055e28000 CR4: 00000000003526f0 Call Trace: lockdep_recursion_finish kernel/locking/lockdep.c:470 [inline] lock_release kernel/locking/lockdep.c:5891 [inline] lock_release+0x170/0x310 kernel/locking/lockdep.c:5875 __raw_spin_unlock include/linux/spinlock_api_smp.h:167 [inline] _raw_spin_unlock+0x16/0x50 kernel/locking/spinlock.c:190 spin_unlock include/linux/spinlock.h:390 [inline] advance_sched+0x6a2/0xd20 net/sched/sch_taprio.c:988 __run_hrtimer kernel/time/hrtimer.c:2032 [inline] __hrtimer_run_queues+0x462/0x9c0 kernel/time/hrtimer.c:2096 hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2215 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline] __sysvec_apic_timer_interrupt+0x109/0x470 arch/x86/kernel/apic/apic.c:1068 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:do_adjtimex+0xd6/0x370 kernel/time/timekeeping.c:3000 Code: 45 85 e4 0f 88 18 01 00 00 e8 86 f1 12 00 4c 89 e8 48 c1 e8 03 42 0f b6 04 38 84 c0 74 08 3c 03 0f 8e 4e 02 00 00 41 8b 45 00 <31> ff 25 00 01 00 00 89 c6 41 89 c5 e8 c9 eb 12 00 65 48 8b 05 c9 RSP: 0018:ffffc9000306fc50 EFLAGS: 00000246 RAX: 00000000000037db RBX: 1ffff9200060df8c RCX: ffffffff81f6eb0c RDX: ffff88807d67a540 RSI: ffffffff81f6eb1a RDI: ffff88807d67a540 RBP: ffffc9000306fd68 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffffffffffff R12: 0000000000000000 R13: ffffc9000306fda8 R14: ffffc9000306fc80 R15: dffffc0000000000 do_clock_adjtime kernel/time/posix-timers.c:1169 [inline] __do_sys_clock_adjtime+0x177/0x290 kernel/time/posix-timers.c:1181 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f9c6319de59 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:00007f9c64055028 EFLAGS: 00000246 ORIG_RAX: 0000000000000131 RAX: ffffffffffffffda RBX: 00007f9c63425fa0 RCX: 00007f9c6319de59 RDX: 0000000000000000 RSI: 0000200000000340 RDI: 0000000000000000 RBP: 00007f9c63233e6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f9c63426038 R14: 00007f9c63425fa0 R15: 00007ffd90bbbf38 rcu: rcu_preempt kthread starved for 10502 jiffies! g46085 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:27592 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5510 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7234 __schedule_loop kernel/sched/core.c:7311 [inline] schedule+0xdd/0x2c0 kernel/sched/core.c:7326 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2325 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 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: 0 UID: 0 PID: 9822 Comm: syz.4.995 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+0x589/0x16c0 kernel/smp.c:892 Code: b8 00 00 00 00 00 fc ff df 48 8b 54 24 08 49 89 d5 49 89 d4 49 c1 ed 03 41 83 e4 07 49 01 c5 41 83 c4 03 e8 c9 95 0c 00 f3 90 <41> 0f b6 45 00 41 38 c4 7c 08 84 c0 0f 85 2c 0f 00 00 8b 45 08 31 RSP: 0018:ffffc9000322f650 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff81fd46fd RDX: ffff888033964a80 RSI: ffffffff81fd46d7 RDI: ffff888033964a80 RBP: ffff8880b8541240 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003 R13: ffffed10170a8249 R14: 0000000000000001 R15: ffff8880b843c880 FS: 0000000000000000(0000) GS:ffff888123de8000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000001700 CR3: 000000002b901000 CR4: 00000000003526f0 Call Trace: on_each_cpu_cond_mask+0x40/0x90 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+0x45f/0x16f0 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] tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:499 [inline] tlb_flush_mmu mm/mmu_gather.c:423 [inline] tlb_finish_mmu+0x3fe/0x810 mm/mmu_gather.c:549 exit_mmap+0x454/0xa00 mm/mmap.c:1313 __mmput+0x12a/0x410 kernel/fork.c:1187 mmput+0x67/0x80 kernel/fork.c:1210 exit_mm kernel/exit.c:615 [inline] do_exit+0x8b1/0x2ae0 kernel/exit.c:997 do_group_exit+0xd5/0x2a0 kernel/exit.c:1152 get_signal+0x1ec7/0x21e0 kernel/signal.c:3046 arch_do_signal_or_restart+0x91/0x7e0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0x139/0x6f0 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+0x666/0x870 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe5beb9de59 Code: Unable to access opcode bytes at 0x7fe5beb9de2f. RSP: 002b:00007fe5bfb150e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007fe5bee26098 RCX: 00007fe5beb9de59 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fe5bee26098 RBP: 00007fe5bee26090 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe5bee26128 R14: 00007ffee7e82cf0 R15: 00007ffee7e82dd8