rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P11636/1:b..l rcu: (detected by 0, t=10502 jiffies, g=37965, q=38 ncpus=2) task:syz.2.1499 state:R running task stack:24896 pid:11636 tgid:11636 ppid:7645 task_flags:0x40044c flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0x1553/0x5240 kernel/sched/core.c:6911 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7238 irqentry_exit+0x599/0x620 kernel/entry/common.c:239 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_release+0x2d7/0x3d0 kernel/locking/lockdep.c:5893 Code: bb ae 10 00 00 00 00 eb b5 e8 95 c7 83 09 f7 c3 00 02 00 00 74 b9 65 48 8b 05 05 75 ae 10 48 3b 44 24 28 75 44 fb 48 83 c4 30 <5b> 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 48 8d 3d 62 30 cd RSP: 0018:ffffc900069bf330 EFLAGS: 00000286 RAX: e98659cd45531200 RBX: 0000000000000202 RCX: 0000000000000046 RDX: 00000000da828343 RSI: ffffffff8d7c2068 RDI: ffffffff8ba67a00 RBP: ffff88802bee48e0 R08: ffffffff8b2681d0 R09: ffffffff8ddcb9c0 R10: 0000000000000000 R11: fffffbfff1ed4e97 R12: 0000000000000002 R13: 0000000000000002 R14: ffff88813fe19658 R15: ffff88802bee3d00 rt_spin_unlock+0x29/0x200 kernel/locking/spinlock_rt.c:80 spin_unlock_irqrestore include/linux/spinlock_rt.h:129 [inline] get_partial_node_bulk mm/slub.c:3785 [inline] __refill_objects_node+0x1e7/0x560 mm/slub.c:7027 refill_objects+0x5e/0x3c0 mm/slub.c:7162 refill_sheaf mm/slub.c:2812 [inline] __pcs_replace_empty_main+0x35c/0x710 mm/slub.c:4615 alloc_from_pcs mm/slub.c:4717 [inline] slab_alloc_node mm/slub.c:4851 [inline] __kmalloc_cache_noprof+0x44e/0x690 mm/slub.c:5375 kmalloc_noprof include/linux/slab.h:950 [inline] slab_free_hook mm/slub.c:2637 [inline] slab_free mm/slub.c:6165 [inline] kmem_cache_free+0x159/0x6b0 mm/slub.c:6295 anon_vma_free mm/rmap.c:137 [inline] __put_anon_vma+0x12a/0x310 mm/rmap.c:2909 put_anon_vma mm/internal.h:215 [inline] unlink_anon_vmas+0x58b/0x730 mm/rmap.c:536 free_pgtables+0x836/0xb70 mm/memory.c:427 exit_mmap+0x490/0xa10 mm/mmap.c:1314 __mmput+0xcb/0x3d0 kernel/fork.c:1175 exit_mm+0x168/0x220 kernel/exit.c:581 do_exit+0x6a2/0x23c0 kernel/exit.c:964 do_group_exit+0x21b/0x2d0 kernel/exit.c:1118 get_signal+0x125c/0x1310 kernel/signal.c:3034 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98 __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 include/linux/entry-common.h:325 [inline] do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1505c6c819 RSP: 002b:00007ffc88fe3178 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffdfc RBX: 00000000000adc4f RCX: 00007f1505c6c819 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007f1505ee5fac RBP: 0000000000000032 R08: 3fffffffffffffff R09: 0000000000000000 R10: 00007ffc88fe3280 R11: 0000000000000246 R12: 00007ffc88fe32a0 R13: 00007f1505ee5fac R14: 00000000000adc81 R15: 00007ffc88fe3280 rcu: rcu_preempt kthread starved for 10405 jiffies! g37965 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:26856 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0x1553/0x5240 kernel/sched/core.c:6911 __schedule_loop kernel/sched/core.c:6993 [inline] schedule+0x164/0x360 kernel/sched/core.c:7008 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 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_{RT,(full)} Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63 Code: 5e 5c 02 e9 13 c4 03 00 cc cc cc 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 f3 3c 25 00 fb f4 cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 RSP: 0018:ffffffff8da07dc0 EFLAGS: 00000242 RAX: 0000000001441451 RBX: ffffffff8199715a RCX: 0000000080000001 RDX: 0000000000000001 RSI: ffffffff8d565a7b RDI: ffffffff8ba67a00 RBP: ffffffff8da07eb0 R08: ffff8880b8833e1b R09: 1ffff110171067c3 R10: dffffc0000000000 R11: ffffed10171067c4 R12: 0000000000000000 R13: 1ffffffff1b605d8 R14: 0000000000000000 R15: 1ffffffff1b605d8 FS: 0000000000000000(0000) GS:ffff888126332000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fc889decd58 CR3: 0000000036bf2000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/kernel/process.c:766 [inline] default_idle+0x9/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x72/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:199 [inline] do_idle+0x36a/0x5f0 kernel/sched/idle.c:352 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:451 rest_init+0x2de/0x300 init/main.c:760 start_kernel+0x385/0x3d0 init/main.c:1210 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x147