rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=06f4/1/0x4000000000000000 softirq=81019/81020 fqs=1 rcu: (detected by 1, t=10502 jiffies, g=92441, q=333 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 16768 Comm: syz.6.2559 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:write_comp_data+0x0/0x90 kernel/kcov.c:246 Code: e9 4e fe ff ff 48 8b 7c 24 08 e8 2b 90 70 00 e9 6d fd ff ff 66 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <65> 8b 05 39 e7 59 12 49 89 f8 49 89 f1 49 89 d2 65 48 8b 3d 10 e7 RSP: 0018:ffffc90000007de0 EFLAGS: 00000046 RAX: 0000000000000001 RBX: 0000000000000001 RCX: ffffffff89c86432 RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000000000000001 RBP: ffff88803454f000 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000 R13: 18c7288e84572cac R14: ffff88803454fc00 R15: ffff88803454fc00 FS: 00007f4eb4dde6c0(0000) GS:ffff888123ddc000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000000240 CR3: 000000005ff32000 CR4: 00000000003526f0 Call Trace: rcu_read_unlock include/linux/rcupdate.h:869 [inline] advance_sched+0x952/0xd20 net/sched/sch_taprio.c:994 __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:wake_up_q+0x6f/0x130 kernel/sched/core.c:1166 Code: a3 00 00 00 48 83 fd 01 0f 84 8a 00 00 00 48 89 eb 48 89 d8 4c 8d a3 48 f5 ff ff 48 c1 e8 03 42 80 3c 28 00 0f 85 8f 00 00 00 <48> 89 d8 48 8b 2b 48 c1 e8 03 42 80 3c 28 00 0f 85 87 00 00 00 48 RSP: 0018:ffffc90003a77c30 EFLAGS: 00000246 RAX: 1ffff110064b6157 RBX: ffff8880325b0ab8 RCX: 0000000000000000 RDX: 1ffff9200074ef97 RSI: 0000000000000004 RDI: ffffc90003a77cb8 RBP: ffffc90003a77d60 R08: 0000000000000000 R09: ffffed1005a6f899 R10: ffff88802d37c4cb R11: 0000000000000000 R12: ffff8880325b0000 R13: dffffc0000000000 R14: ffff88802d37c4f0 R15: ffff88802d37c000 futex_wake+0x4f4/0x5e0 kernel/futex/waitwake.c:225 do_futex+0x2b2/0x440 kernel/futex/syscalls.c:138 __do_sys_futex kernel/futex/syscalls.c:210 [inline] __se_sys_futex kernel/futex/syscalls.c:191 [inline] __x64_sys_futex+0x34f/0x4d0 kernel/futex/syscalls.c:191 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: 0033:0x7f4eb3f9e019 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:00007f4eb4dde0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00007f4eb4225fa8 RCX: 00007f4eb3f9e019 RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f4eb4225fac RBP: 00007f4eb4225fa0 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f4eb4226038 R14: 00007ffefb63ddb0 R15: 00007ffefb63de98 rcu: rcu_preempt kthread starved for 10500 jiffies! g92441 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: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: 1 UID: 0 PID: 6836 Comm: kworker/u8:25 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0x58e/0x1870 kernel/smp.c:912 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 64 99 0c 00 f3 90 <41> 0f b6 45 00 41 38 c4 7c 08 84 c0 0f 85 a8 10 00 00 8b 45 08 31 RSP: 0018:ffffc90003ac7858 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff81fdc702 RDX: ffff888077622540 RSI: ffffffff81fdc6dc RDI: ffff888077622540 RBP: ffff8880b8443680 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003 R13: ffffed10170886d1 R14: 0000000000000001 R15: ffff8880b853c880 FS: 0000000000000000(0000) GS:ffff888123edc000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b32120000 CR3: 000000000e994000 CR4: 00000000003526f0 Call Trace: on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1077 on_each_cpu include/linux/smp.h:72 [inline] smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2773 [inline] smp_text_poke_batch_finish+0x337/0xc60 arch/x86/kernel/alternative.c:2983 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 jump_label_update+0x37a/0x550 kernel/jump_label.c:910 static_key_enable_cpuslocked+0x1bc/0x270 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate mm/kfence/core.c:911 [inline] toggle_allocation_gate+0xfe/0x2d0 mm/kfence/core.c:903 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322 process_scheduled_works kernel/workqueue.c:3405 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486 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 watchdog: BUG: soft lockup - CPU#1 stuck for 246s! [kworker/u8:25:6836] Modules linked in: irq event stamp: 4035636 hardirqs last enabled at (4035635): [] irqentry_exit_to_kernel_mode_after_preempt include/linux/irq-entry-common.h:507 [inline] hardirqs last enabled at (4035635): [] irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:542 [inline] hardirqs last enabled at (4035635): [] irqentry_exit+0x24d/0xa00 kernel/entry/common.c:167 hardirqs last disabled at (4035636): [] sysvec_apic_timer_interrupt+0xe/0xc0 arch/x86/kernel/apic/apic.c:1062 softirqs last enabled at (4035634): [] __do_softirq kernel/softirq.c:656 [inline] softirqs last enabled at (4035634): [] invoke_softirq kernel/softirq.c:496 [inline] softirqs last enabled at (4035634): [] __irq_exit_rcu+0x162/0x210 kernel/softirq.c:735 softirqs last disabled at (4035583): [] __do_softirq kernel/softirq.c:656 [inline] softirqs last disabled at (4035583): [] invoke_softirq kernel/softirq.c:496 [inline] softirqs last disabled at (4035583): [] __irq_exit_rcu+0x162/0x210 kernel/softirq.c:735 CPU: 1 UID: 0 PID: 6836 Comm: kworker/u8:25 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0x593/0x1870 kernel/smp.c:912 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 64 99 0c 00 f3 90 41 0f b6 45 00 <41> 38 c4 7c 08 84 c0 0f 85 a8 10 00 00 8b 45 08 31 ff 83 e0 01 41 RSP: 0018:ffffc90003ac7858 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff81fdc702 RDX: ffff888077622540 RSI: ffffffff81fdc6dc RDI: ffff888077622540 RBP: ffff8880b8443680 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003 R13: ffffed10170886d1 R14: 0000000000000001 R15: ffff8880b853c880 FS: 0000000000000000(0000) GS:ffff888123edc000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b32120000 CR3: 000000000e994000 CR4: 00000000003526f0 Call Trace: on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1077 on_each_cpu include/linux/smp.h:72 [inline] smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2773 [inline] smp_text_poke_batch_finish+0x337/0xc60 arch/x86/kernel/alternative.c:2983 arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146 jump_label_update+0x37a/0x550 kernel/jump_label.c:910 static_key_enable_cpuslocked+0x1bc/0x270 kernel/jump_label.c:210 static_key_enable+0x1a/0x20 kernel/jump_label.c:223 toggle_allocation_gate mm/kfence/core.c:911 [inline] toggle_allocation_gate+0xfe/0x2d0 mm/kfence/core.c:903 process_one_work+0xa23/0x1940 kernel/workqueue.c:3322 process_scheduled_works kernel/workqueue.c:3405 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486 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 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 16768 Comm: syz.6.2559 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 RIP: 0010:kasan_mem_to_shadow include/linux/kasan.h:66 [inline] RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:140 [inline] RIP: 0010:memory_is_poisoned mm/kasan/generic.c:172 [inline] RIP: 0010:check_region_inline mm/kasan/generic.c:191 [inline] RIP: 0010:kasan_check_range+0x61/0x1e0 mm/kasan/generic.c:200 Code: 00 80 ff ff 48 39 c7 0f 82 c2 00 00 00 4c 8d 54 37 ff 48 89 fd 48 b8 00 00 00 00 00 fc ff df 4d 89 d1 48 c1 ed 03 49 c1 e9 03 <48> 01 c5 49 01 c1 48 89 e8 49 8d 59 01 48 89 da 48 29 ea 48 83 fa RSP: 0018:ffffc90000007cd8 EFLAGS: 00000806 RAX: dffffc0000000000 RBX: ffffffff9b8f5280 RCX: ffffffff81e64419 RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffffff9b8f5280 RBP: 1ffffffff371ea50 R08: 0000000000000001 R09: 1ffffffff371ea50 R10: ffffffff9b8f5283 R11: 0000000000000000 R12: 1ffff92000000fa0 R13: ffffffff9b8f5290 R14: ffff888035dc7300 R15: 1ffff92000000fb8 FS: 00007f4eb4dde6c0(0000) GS:ffff888123ddc000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200000000240 CR3: 000000005ff32000 CR4: 00000000003526f0 Call Trace: instrument_atomic_read_write include/linux/instrumented.h:112 [inline] atomic_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:1300 [inline] queued_spin_lock include/asm-generic/qspinlock.h:111 [inline] do_raw_spin_lock+0x119/0x260 kernel/locking/spinlock_debug.c:116 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock_irqsave+0x42/0x60 kernel/locking/spinlock.c:166 debug_object_deactivate+0x135/0x3b0 lib/debugobjects.c:936 debug_hrtimer_deactivate kernel/time/hrtimer.c:490 [inline] __run_hrtimer kernel/time/hrtimer.c:2000 [inline] __hrtimer_run_queues+0x2e9/0x9c0 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:wake_up_q+0x6f/0x130 kernel/sched/core.c:1166 Code: a3 00 00 00 48 83 fd 01 0f 84 8a 00 00 00 48 89 eb 48 89 d8 4c 8d a3 48 f5 ff ff 48 c1 e8 03 42 80 3c 28 00 0f 85 8f 00 00 00 <48> 89 d8 48 8b 2b 48 c1 e8 03 42 80 3c 28 00 0f 85 87 00 00 00 48 RSP: 0018:ffffc90003a77c30 EFLAGS: 00000246 RAX: 1ffff110064b6157 RBX: ffff8880325b0ab8 RCX: 0000000000000000 RDX: 1ffff9200074ef97 RSI: 0000000000000004 RDI: ffffc90003a77cb8 RBP: ffffc90003a77d60 R08: 0000000000000000 R09: ffffed1005a6f899 R10: ffff88802d37c4cb R11: 0000000000000000 R12: ffff8880325b0000 R13: dffffc0000000000 R14: ffff88802d37c4f0 R15: ffff88802d37c000 futex_wake+0x4f4/0x5e0 kernel/futex/waitwake.c:225 do_futex+0x2b2/0x440 kernel/futex/syscalls.c:138 __do_sys_futex kernel/futex/syscalls.c:210 [inline] __se_sys_futex kernel/futex/syscalls.c:191 [inline] __x64_sys_futex+0x34f/0x4d0 kernel/futex/syscalls.c:191 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: 0033:0x7f4eb3f9e019 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:00007f4eb4dde0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: ffffffffffffffda RBX: 00007f4eb4225fa8 RCX: 00007f4eb3f9e019 RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f4eb4225fac RBP: 00007f4eb4225fa0 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f4eb4226038 R14: 00007ffefb63ddb0 R15: 00007ffefb63de98