rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6219/1:b..l (detected by 0, t=10502 jiffies, g=25921, q=147 ncpus=2) task:syz.5.456 state:R running task stack:24816 pid:6219 ppid:5251 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5245 [inline] __schedule+0x107f/0x4030 kernel/sched/core.c:6562 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6874 irqentry_exit+0x63/0x70 kernel/entry/common.c:439 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:lock_acquire+0x225/0x4a0 kernel/locking/lockdep.c:5680 Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3d 04 f8 0f 85 f0 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 44 3d 00 00 00 00 00 43 c7 44 3d 08 00 00 00 00 65 48 8b 04 RSP: 0018:ffffc90004347da0 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: cc0389b487dfb400 RDX: 0000000000000000 RSI: ffffffff8a8c2920 RDI: ffffffff8adf42e0 RBP: ffffc90004347ec0 R08: dffffc0000000000 R09: 1ffffffff2162048 R10: dffffc0000000000 R11: fffffbfff2162049 R12: 0000000000000000 R13: 1ffff92000868fc0 R14: 0000000000000246 R15: dffffc0000000000 rcu_lock_acquire include/linux/rcupdate.h:350 [inline] rcu_read_lock include/linux/rcupdate.h:791 [inline] __task_pid_nr_ns+0x44/0x460 kernel/pid.c:497 task_tgid_vnr include/linux/sched.h:1635 [inline] __ia32_sys_getpid+0x19/0x20 kernel/sys.c:953 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fa727997c17 RSP: 002b:00007ffe8c5429c8 EFLAGS: 00000202 ORIG_RAX: 0000000000000027 RAX: ffffffffffffffda RBX: 00007ffe8c542b30 RCX: 00007fa727997c17 RDX: 00007ffe8c542a00 RSI: 00007ffe8c542b30 RDI: 0000000000000021 RBP: 0000000000000000 R08: 00007fa727c10000 R09: 00007fa727c12000 R10: 00000000815104a0 R11: 0000000000000202 R12: 00007fa727c26038 R13: 0000000000011db7 R14: ffffffff84154ec6 R15: 00007fa728755720 rcu: rcu_preempt kthread starved for 10487 jiffies! g25921 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:27712 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5245 [inline] __schedule+0x107f/0x4030 kernel/sched/core.c:6562 schedule+0xb9/0x180 kernel/sched/core.c:6638 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2168 rcu_gp_fqs_loop+0x303/0x1350 kernel/rcu/tree.c:1706 rcu_gp_kthread+0x99/0x3b0 kernel/rcu/tree.c:1905 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 RIP: 0010:default_idle+0xb/0x10 arch/x86/kernel/process.c:742 Code: 48 89 df e8 67 01 99 f7 e9 44 ff ff ff e8 8d 03 f6 ff 00 00 cc cc 00 00 cc cc 00 00 cc cc 00 66 90 0f 00 2d f7 60 4c 00 fb f4 0f 1f 40 00 41 57 41 56 53 49 be 00 00 00 00 00 fc ff df 65 48 RSP: 0018:ffffffff8c807d88 EFLAGS: 000002c6 RAX: 64330f2c20398900 RBX: ffffffff8a3a4b17 RCX: 64330f2c20398900 RDX: 0000000000000001 RSI: ffffffff8a8c17a0 RDI: ffffffff8adf42e0 RBP: ffffffff8c807ec0 R08: ffff8880b8e3580b R09: 1ffff110171c6b01 R10: dffffc0000000000 R11: ffffed10171c6b02 R12: 0000000000000000 R13: dffffc0000000000 R14: ffffffff8c8bc740 R15: 1ffffffff1900fbc FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe0953556b8 CR3: 000000005c253000 CR4: 00000000003506f0 DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000002 DR3: ffffffffefffff15 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: default_idle_call+0x84/0xc0 kernel/sched/idle.c:109 cpuidle_idle_call kernel/sched/idle.c:199 [inline] do_idle+0x250/0x680 kernel/sched/idle.c:323 cpu_startup_entry+0x3f/0x60 kernel/sched/idle.c:422 rest_init+0x2dc/0x300 init/main.c:745 arch_call_rest_init+0xa/0xa init/main.c:904 start_kernel+0x493/0x53c init/main.c:1151 secondary_startup_64_no_verify+0xcf/0xdb