rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=74d4/1/0x4000000000000000 softirq=68478/68479 fqs=1 rcu: (detected by 1, t=10502 jiffies, g=77997, q=279 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 13566 Comm: syz.5.2046 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:debug_object_deactivate+0x2d9/0x3b0 lib/debugobjects.c:943 Code: 48 8d 7c 24 40 e8 87 d4 ff ff e9 f3 fd ff ff 44 39 25 5b d3 d4 0b 7d d6 44 89 25 52 d3 d4 0b eb cd 83 f8 04 0f 84 47 ff ff ff <48> 89 ce 48 89 d7 e8 bc 08 8a 06 e9 c8 fd ff ff c7 43 10 02 00 00 RSP: 0018:ffffc90000007da0 EFLAGS: 00000046 RAX: 0000000000000000 RBX: ffff888080a175b0 RCX: 0000000000000006 RDX: ffffffff9b3b4fe8 RSI: 0000000000000000 RDI: ffff888080a175c4 RBP: ffffc90000007e78 R08: 0000000000000001 R09: fffff52000000fa2 R10: 0000000000000003 R11: 0000000000000001 R12: 0000000000000001 R13: dffffc0000000000 R14: ffff88805414a300 R15: 1ffff92000000fb6 FS: 00007f10cc9d06c0(0000) GS:ffff888124387000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 00000000850c3000 CR4: 00000000003526f0 Call Trace: debug_hrtimer_deactivate kernel/time/hrtimer.c:490 [inline] __run_hrtimer kernel/time/hrtimer.c:1898 [inline] __hrtimer_run_queues+0x2f0/0xa00 kernel/time/hrtimer.c:1994 hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2113 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] __sysvec_apic_timer_interrupt+0x10b/0x460 arch/x86/kernel/apic/apic.c:1067 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1061 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:198 Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 d6 0e 58 f6 48 89 df e8 ae 5e 58 f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 b5 2a 48 f6 65 8b 05 6e 0d 7d 08 85 c0 74 16 5b RSP: 0018:ffffc900051efb28 EFLAGS: 00000246 RAX: 0000000000000006 RBX: ffffffff9b194118 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8df0fe0d RDI: ffffffff8c1c4780 RBP: 0000000000000286 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000007700000000 R12: ffffffff9b193e80 R13: 0000000000000001 R14: ffffc900051efc80 R15: 7fffffffffffffff class_raw_spinlock_irqsave_destructor include/linux/spinlock.h:571 [inline] __do_adjtimex+0x892/0xe70 kernel/time/timekeeping.c:2871 do_adjtimex+0xa0/0x370 kernel/time/timekeeping.c:2914 do_clock_adjtime kernel/time/posix-timers.c:1154 [inline] __do_sys_clock_adjtime+0x177/0x290 kernel/time/posix-timers.c:1166 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: 0033:0x7f10cbb9ce59 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:00007f10cc9d0028 EFLAGS: 00000246 ORIG_RAX: 0000000000000131 RAX: ffffffffffffffda RBX: 00007f10cbe16090 RCX: 00007f10cbb9ce59 RDX: 0000000000000000 RSI: 0000200000000040 RDI: 0000000000000000 RBP: 00007f10cbc32d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f10cbe16128 R14: 00007f10cbe16090 R15: 00007ffc60daa168 rcu: rcu_preempt kthread starved for 10500 jiffies! g77997 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:27992 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1295/0x67a0 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7283 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297 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: 1 UID: 0 PID: 13562 Comm: syz.1.2059 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:get_current arch/x86/include/asm/current.h:23 [inline] RIP: 0010:write_comp_data+0x10/0x90 kernel/kcov.c:245 Code: 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 65 8b 05 b9 e5 00 12 49 89 f8 49 89 f1 49 89 d2 <65> 48 8b 3d 90 e5 00 12 a9 00 01 ff 00 74 1b f6 c4 01 74 07 a9 00 RSP: 0018:ffffc9000506f368 EFLAGS: 00000202 RAX: 0000000000000003 RBX: 0000000000000000 RCX: ffffffff81fc2dfd RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000005 RBP: ffff8880b8443560 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003 R13: ffffed10170886ad R14: 0000000000000001 R15: ffff8880b853c800 FS: 00007f70b0e816c0(0000) GS:ffff888124487000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f10cc9cfff8 CR3: 000000008e28d000 CR4: 00000000003526f0 Call Trace: csd_lock_wait kernel/smp.c:342 [inline] smp_call_function_many_cond+0x5ad/0x1700 kernel/smp.c:892 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 pmdp_invalidate+0x269/0x380 mm/pgtable-generic.c:206 clear_soft_dirty_pmd fs/proc/task_mmu.c:1658 [inline] clear_refs_pte_range+0xad3/0x10b0 fs/proc/task_mmu.c:1692 walk_pmd_range mm/pagewalk.c:148 [inline] walk_pud_range mm/pagewalk.c:239 [inline] walk_p4d_range mm/pagewalk.c:280 [inline] walk_pgd_range+0xc1a/0x1dd0 mm/pagewalk.c:321 __walk_page_range+0x171/0x850 mm/pagewalk.c:429 walk_page_range_mm_unsafe+0x563/0xa10 mm/pagewalk.c:525 walk_page_range+0x63/0x90 mm/pagewalk.c:604 clear_refs_write+0x923/0xb00 fs/proc/task_mmu.c:1827 do_loop_readv_writev fs/read_write.c:852 [inline] do_loop_readv_writev fs/read_write.c:837 [inline] vfs_writev+0x5ea/0xe10 fs/read_write.c:1061 do_writev+0x13e/0x340 fs/read_write.c:1105 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: 0033:0x7f70aff9ce59 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:00007f70b0e81028 EFLAGS: 00000246 ORIG_RAX: 0000000000000014 RAX: ffffffffffffffda RBX: 00007f70b0215fa0 RCX: 00007f70aff9ce59 RDX: 0000000000000001 RSI: 0000200000000100 RDI: 0000000000000003 RBP: 00007f70b0032d6f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f70b0216038 R14: 00007f70b0215fa0 R15: 00007ffe87480758