rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...0: (0 ticks this GP) idle=9784/0/0x1 softirq=61501/61501 fqs=493 rcu: hardirqs softirqs csw/system rcu: number: 0 0 0 rcu: cputime: 0 0 0 ==> 52350(ms) rcu: (detected by 0, t=10502 jiffies, g=76189, q=298 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 08/05/2026 RIP: 0010:write_comp_data+0x90/0xa0 kernel/kcov.c:268 Code: 00 00 4a 8d 14 dd 28 00 00 00 48 39 d7 72 1b 48 83 c6 01 48 89 30 4c 89 44 10 e0 4c 89 4c 10 e8 4c 89 54 10 f0 4a 89 4c d8 20 9b 6c c7 09 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 RSP: 0018:ffffc90000a18e40 EFLAGS: 00000046 RAX: 8000000001000002 RBX: ffff88807f01b300 RCX: ffffffff81f7637b RDX: 0000000001000002 RSI: 000000000000001f RDI: ffff88801fa84b00 RBP: ffff8880b8528640 R08: 0000000000000005 R09: 000000000000001f R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000 R13: ffff8880b8528500 R14: 0000000000000000 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff888123c5d000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2ef00ff8 CR3: 0000000035fbe000 CR4: 00000000003526f0 Call Trace: __remove_hrtimer+0x16b/0x650 kernel/time/hrtimer.c:1183 __run_hrtimer kernel/time/hrtimer.c:2047 [inline] __hrtimer_run_queues+0x352/0x9c0 kernel/time/hrtimer.c:2124 hrtimer_interrupt+0x441/0xaa0 kernel/time/hrtimer.c:2243 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: 58 9b 02 e9 43 50 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 c3 76 1b 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:ffffc900001a7e00 EFLAGS: 00000242 RAX: 00000000031b6b61 RBX: ffff88801fa84b00 RCX: ffffffff8bd04185 RDX: 0000000000000001 RSI: ffffffff8e3ebf9c RDI: ffffffff8c621080 RBP: ffffed1003f50960 R08: 0000000000000001 R09: ffffed10170a67bd R10: ffff8880b8533deb R11: 0000000000000001 R12: 0000000000000000 R13: 0000000000000000 R14: 1ffff92000034fc4 R15: dffffc0000000000 arch_safe_halt arch/x86/include/asm/paravirt.h:62 [inline] default_idle+0x9/0x10 arch/x86/kernel/process.c:768 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:199 [inline] do_idle+0x3ae/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 1930 jiffies! g76189 f0x0 RCU_GP_WAIT_FQS(5) ->state=R ->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:27560 pid:17 tgid:17 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5526 [inline] __schedule+0x1259/0x6920 kernel/sched/core.c:7276 __schedule_loop kernel/sched/core.c:7353 [inline] schedule+0xdd/0x2c0 kernel/sched/core.c:7368 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x8f0 kernel/rcu/tree.c:2122 rcu_gp_kthread+0x17a/0x220 kernel/rcu/tree.c:2330 kthread+0x373/0x450 kernel/kthread.c:436 ret_from_fork+0x730/0xd60 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: 0 Comm: swapper/0 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/05/2026 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:64 Code: 58 9b 02 e9 43 50 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 c3 76 1b 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:ffffffff8ea07cf0 EFLAGS: 00000246 RAX: 000000000179f3f3 RBX: ffffffff8ea91500 RCX: ffffffff8bd04185 RDX: 0000000000000001 RSI: ffffffff8e3ebf9c RDI: ffffffff8c621080 RBP: fffffbfff1d522a0 R08: 0000000000000001 R09: ffffed10170867bd R10: ffff8880b8433deb R11: 0000000000000001 R12: 0000000000000000 R13: 0000000000000000 R14: 1ffffffff1d40fa2 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff888123b5d000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00002000000f5030 CR3: 000000007568a000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:62 [inline] default_idle+0x9/0x10 arch/x86/kernel/process.c:768 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:199 [inline] do_idle+0x3ae/0x5b0 kernel/sched/idle.c:355 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:454 rest_init+0x2d3/0x2e0 init/main.c:727 start_kernel+0x48e/0x490 init/main.c:1185 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x12b/0x130 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x158