watchdog: BUG: soft lockup - CPU#1 stuck for 143s! [syz.2.231:6990] Modules linked in: irq event stamp: 67748 hardirqs last enabled at (67747): [] irqentry_exit+0x5dd/0x660 kernel/entry/common.c:219 hardirqs last disabled at (67748): [] sysvec_apic_timer_interrupt+0xe/0xc0 arch/x86/kernel/apic/apic.c:1056 softirqs last enabled at (0): [] rcu_lock_acquire include/linux/rcupdate.h:331 [inline] softirqs last enabled at (0): [] rcu_read_lock include/linux/rcupdate.h:867 [inline] softirqs last enabled at (0): [] copy_process+0x915/0x3960 kernel/fork.c:2091 softirqs last disabled at (0): [<0000000000000000>] 0x0 CPU: 1 UID: 0 PID: 6990 Comm: syz.2.231 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0xe77/0x1250 kernel/smp.c:877 Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 12 9a 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 4d 95 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 31 95 RSP: 0018:ffffc90003b975e0 EFLAGS: 00000293 RAX: ffffffff81b414ef RBX: 1ffff11017108b21 RCX: ffff88802a805ac0 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc90003b97720 R08: 0000000000000000 R09: 0000000000000000 R10: dffffc0000000000 R11: fffffbfff1db668f R12: ffff8880b8845908 R13: dffffc0000000000 R14: ffff8880b893c8c0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888126def000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c35b3f9 CR3: 000000000d3a8000 CR4: 00000000003526f0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1382 [inline] flush_tlb_mm_range+0x60a/0x1170 arch/x86/mm/tlb.c:1472 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+0x439/0xb10 mm/mmap.c:1290 __mmput+0xcb/0x3d0 kernel/fork.c:1173 exit_mm+0x169/0x230 kernel/exit.c:581 do_exit+0x627/0x22f0 kernel/exit.c:959 do_group_exit+0x21c/0x2d0 kernel/exit.c:1112 get_signal+0x125d/0x1310 kernel/signal.c:3034 arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline] exit_to_user_mode_loop+0x87/0x4e0 kernel/entry/common.c:75 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] do_syscall_64+0x2b7/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe4f4abf749 Code: Unable to access opcode bytes at 0x7fe4f4abf71f. RSP: 002b:00007fe4f2ce40e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007fe4f4d16188 RCX: 00007fe4f4abf749 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fe4f4d16188 RBP: 00007fe4f4d16180 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe4f4d16218 R14: 00007ffc7ceffe10 R15: 00007ffc7ceffef8 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 18 Comm: rcu_preempt Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:num_possible_cpus include/linux/cpumask.h:1222 [inline] RIP: 0010:mm_get_cid+0xab/0x130 kernel/sched/sched.h:3759 Code: 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 49 c7 c5 c8 84 01 8d 49 c1 ed 03 bd 00 00 00 80 eb 07 44 89 f0 f7 d8 71 d4 f3 90 <43> 0f b6 44 25 00 84 c0 75 41 44 8b 3d 6c 8b 6f 0b 48 89 df 4c 89 RSP: 0018:ffffc90000177968 EFLAGS: 00000887 RAX: 0000000080000000 RBX: ffff8880106f0c10 RCX: 1ffff110047d167c RDX: 0000000000000002 RSI: 0000000000000002 RDI: ffff8880106f0c10 RBP: 0000000080000000 R08: 0000000000000000 R09: 0000000000000000 R10: dffffc0000000000 R11: ffffed10020de153 R12: dffffc0000000000 R13: 1ffffffff1a03099 R14: 0000000080000000 R15: 0000000000000002 FS: 0000000000000000(0000) GS:ffff888126cef000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2ef19ff8 CR3: 0000000028148000 CR4: 00000000003526f0 Call Trace: mm_cid_from_cpu kernel/sched/sched.h:3820 [inline] mm_cid_schedin kernel/sched/sched.h:3870 [inline] mm_cid_switch_to kernel/sched/sched.h:3886 [inline] context_switch kernel/sched/core.c:5245 [inline] __schedule+0x212a/0x5070 kernel/sched/core.c:6863 preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:7047 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0x74/0x80 kernel/locking/spinlock.c:194 rcu_sr_normal_complete kernel/rcu/tree.c:1651 [inline] rcu_sr_normal_gp_cleanup kernel/rcu/tree.c:1722 [inline] rcu_gp_cleanup+0xc7e/0xed0 kernel/rcu/tree.c:2249 rcu_gp_kthread+0xa7/0x390 kernel/rcu/tree.c:2289 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246