rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (5 ticks this GP) idle=011c/0/0x1 softirq=244665/244680 fqs=1 rcu: (detected by 0, t=10504 jiffies, g=226505, q=1846 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 0 Comm: swapper/1 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:__sanitizer_cov_trace_const_cmp1+0x8/0x20 kernel/kcov.c:300 Code: bf 06 00 00 00 e9 b8 fe ff ff 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 0c 24 <40> 0f b6 d6 40 0f b6 f7 bf 01 00 00 00 e9 86 fe ff ff 66 0f 1f 44 RSP: 0018:ffffc90000a08e90 EFLAGS: 00000046 RAX: 0000000000000001 RBX: dffffc0000000000 RCX: ffffffff81f5273b RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 000000000000a997 R12: ffff888056319300 R13: ffffffff89a41220 R14: ffff8880b8528640 R15: ffff8880b8528690 FS: 0000000000000000(0000) GS:ffff888124425000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000563318b10be0 CR3: 000000005f387000 CR4: 00000000003526f0 Call Trace: trace_hrtimer_expire_entry include/trace/events/timer.h:261 [inline] __run_hrtimer kernel/time/hrtimer.c:2029 [inline] __hrtimer_run_queues+0x73b/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:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:64 Code: 76 89 02 e9 c3 48 03 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 83 07 16 00 fb f4 cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffc90000197e00 EFLAGS: 00000246 RAX: 000000000bb40114 RBX: ffff88801e2c2540 RCX: ffffffff8b9592b5 RDX: 0000000000000001 RSI: ffffffff8c1d0d00 RDI: ffffffff81de38e7 RBP: ffffed1003c584a8 R08: 0000000000000000 R09: ffffed10170a678d R10: ffff8880b8533c6b R11: 000000000000a997 R12: 0000000000000000 R13: 0000000000000000 R14: 1ffff92000032fc4 R15: dffffc0000000000 arch_safe_halt arch/x86/include/asm/paravirt.h:62 [inline] default_idle+0x9/0x10 arch/x86/kernel/process.c:767 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:199 [inline] do_idle+0x3a7/0x5b0 kernel/sched/idle.c:355 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:454 start_secondary+0x21d/0x2d0 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x158 rcu: rcu_preempt kthread starved for 10494 jiffies! g226505 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:28312 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5504 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7228 __schedule_loop kernel/sched/core.c:7307 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7322 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: 4972 Comm: udevd 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:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0x58e/0x16c0 kernel/smp.c:892 Code: 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 39 93 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 ff 83 e0 01 41 RSP: 0018:ffffc900035bf618 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff81fcdd4d RDX: ffff888039254a80 RSI: ffffffff81fcdd27 RDI: ffff888039254a80 RBP: ffff8880b8541080 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003 R13: ffffed10170a8211 R14: 0000000000000001 R15: ffff8880b843c700 FS: 00007feb6ebb9880(0000) GS:ffff888124325000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f4e6b6b3708 CR3: 000000002acc3000 CR4: 00000000003526f0 DR0: ffffffffffffffff DR1: 00000000000001f7 DR2: 00000000ffffffff DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400 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 dup_mmap+0x1307/0x21b0 mm/mmap.c:1905 dup_mm kernel/fork.c:1537 [inline] copy_mm kernel/fork.c:1589 [inline] copy_process+0x4588/0x7ff0 kernel/fork.c:2287 kernel_clone+0x176/0x9d0 kernel/fork.c:2745 __do_sys_clone+0xd9/0x120 kernel/fork.c:2886 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: 0033:0x7feb6e4f1636 Code: 89 df e8 6d e8 f6 ff 45 31 c0 31 d2 31 f6 64 48 8b 04 25 10 00 00 00 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 52 89 c5 85 c0 75 31 64 48 8b 04 25 10 00 00 RSP: 002b:00007ffc1a6b7a50 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007ffc1a6b7a58 RCX: 00007feb6e4f1636 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 00005633188d62c0 R08: 0000000000000000 R09: 0000563318b0c020 R10: 00007feb6ebb9b50 R11: 0000000000000246 R12: 00007ffc1a6b7e10 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000