rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P9235/1:b..l (detected by 0, t=10502 jiffies, g=57145, q=520 ncpus=2) task:syz-executor state:R running task stack:22688 pid:9235 ppid:9207 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873 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:task_css include/linux/cgroup.h:509 [inline] RIP: 0010:task_freezer kernel/cgroup/legacy_freezer.c:58 [inline] RIP: 0010:cgroup_freezing+0xd3/0x340 kernel/cgroup/legacy_freezer.c:71 Code: 00 48 c7 c2 e0 b2 8e 8a e8 8a 00 e9 ff 49 bc 00 00 00 00 00 fc ff df 4d 8d b7 50 13 00 00 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 <74> 08 4c 89 f7 e8 33 5c 56 00 4d 8b 36 e8 3b 07 9d 08 89 c5 31 ff RSP: 0018:ffffc90004947b60 EFLAGS: 00000246 RAX: 1ffff1100600fd92 RBX: ffffffff817a9fdc RCX: ffff88803007d940 RDX: 0000000000000000 RSI: ffffffff8adef000 RDI: ffffffff8adeefc0 RBP: 0000000000000001 R08: dffffc0000000000 R09: fffffbfff215c449 R10: fffffbfff215c449 R11: 1ffffffff215c448 R12: dffffc0000000000 R13: 0000000000000000 R14: ffff88803007ec90 R15: ffff88803007d940 freezing_slow_path+0xb7/0x150 kernel/freezer.c:46 freezing include/linux/freezer.h:37 [inline] try_to_freeze include/linux/freezer.h:54 [inline] get_signal+0x12ba/0x1350 kernel/signal.c:2661 arch_do_signal_or_restart+0xb0/0x1230 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f900bf85117 RSP: 002b:00007ffe824796e0 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 0000000000000060 RCX: 00007f900bf85117 RDX: 0000000040000001 RSI: 00007ffe8247974c RDI: 00000000ffffffff RBP: 00007ffe8247974c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000001388 R13: 00000000000927c0 R14: 00000000000a82d5 R15: 00007ffe824797a0 rcu: rcu_preempt kthread starved for 8844 jiffies! g57145 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:27840 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6730 preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6754 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0xf6/0x100 kernel/locking/spinlock.c:194 __mod_timer+0x8ee/0xd20 kernel/time/timer.c:1118 schedule_timeout+0x157/0x280 kernel/time/timer.c:1964 rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706 rcu_gp_kthread+0x95/0x380 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: 10405 Comm: syz.7.1198 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline] RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202 Code: f5 ff 0f 1f 00 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 0e b9 41 f7 48 89 df e8 66 7e 42 f7 e8 81 70 65 f7 fb bf 01 00 00 00 c6 fb 35 f7 65 8b 05 c7 b4 e0 75 85 c0 74 02 5b c3 e8 14 c6 de RSP: 0018:ffffc90015a37bb8 EFLAGS: 00000286 RAX: d6846194fb2c2b00 RBX: ffff888033461bc0 RCX: d6846194fb2c2b00 RDX: dffffc0000000000 RSI: ffffffff8a8c0500 RDI: 0000000000000001 RBP: ffff888033461e58 R08: dffffc0000000000 R09: ffffed100668c379 R10: ffffed100668c379 R11: 1ffff1100668c378 R12: 1ffff1100668c3cb R13: 0000000000000011 R14: dffffc0000000000 R15: 0000000000000000 FS: 00007fd592c096c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fd591fe6098 CR3: 00000000734ca000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 000000000000000c DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: spin_unlock_irq include/linux/spinlock.h:401 [inline] get_signal+0x1163/0x1350 kernel/signal.c:2874 arch_do_signal_or_restart+0xb0/0x1230 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fd591d8efc9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fd592c090e8 EFLAGS: 00000246 RAX: fffffffffffffffc RBX: 00007fd591fe6098 RCX: 00007fd591d8efc9 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fd591fe6098 RBP: 00007fd591fe6090 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fd591fe6128 R14: 00007ffc18ca1b40 R15: 00007ffc18ca1c28