syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4306/1:b..l
	(detected by 0, t=10502 jiffies, g=3797, q=58 ncpus=2)
task:syz-executor916 state:R  running task     stack:0     pid:4306  ppid:4303   flags:0x00000004
Call trace:
 __switch_to+0x308/0x598 arch/arm64/kernel/process.c:553
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0xef4/0x1d44 kernel/sched/core.c:6561
 preempt_schedule_irq+0x8c/0x1b8 kernel/sched/core.c:6873
 arm64_preempt_schedule_irq arch/arm64/kernel/entry-common.c:265 [inline]
 __el1_irq arch/arm64/kernel/entry-common.c:474 [inline]
 el1_interrupt+0x4c/0x68 arch/arm64/kernel/entry-common.c:486
 el1h_64_irq_handler+0x18/0x24 arch/arm64/kernel/entry-common.c:491
 el1h_64_irq+0x64/0x68 arch/arm64/kernel/entry.S:581
 arch_local_irq_restore+0x8/0x10 arch/arm64/include/asm/irqflags.h:122
 lock_is_held include/linux/lockdep.h:283 [inline]
 rcu_read_lock_sched_held+0x38/0xb4 kernel/rcu/update.c:125
 task_css include/linux/cgroup.h:509 [inline]
 mem_cgroup_from_task+0x50/0x120 mm/memcontrol.c:985
 get_obj_cgroup_from_current+0x294/0x540 mm/memcontrol.c:3025
 memcg_slab_pre_alloc_hook mm/slab.h:485 [inline]
 slab_pre_alloc_hook mm/slab.h:715 [inline]
 slab_alloc_node mm/slub.c:3318 [inline]
 __kmem_cache_alloc_node+0xdc/0x388 mm/slub.c:3437
 __do_kmalloc_node mm/slab_common.c:935 [inline]
 __kmalloc_node+0xcc/0x1d0 mm/slab_common.c:943
 kmalloc_node include/linux/slab.h:589 [inline]
 kvmalloc_node+0x84/0x1e4 mm/util.c:581
 kvmalloc include/linux/slab.h:716 [inline]
 alloc_fdtable+0x148/0x238 fs/file.c:138
 dup_fd+0x6a0/0x9a0 fs/file.c:337
 copy_files+0x68/0x100 kernel/fork.c:1636
 copy_process+0x1614/0x38f8 kernel/fork.c:2254
 kernel_clone+0x1d8/0x98c kernel/fork.c:2681
 __do_sys_clone kernel/fork.c:2822 [inline]
 __se_sys_clone kernel/fork.c:2790 [inline]
 __arm64_sys_clone+0x1e0/0x258 kernel/fork.c:2790
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
 do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
 el0_svc+0x58/0x168 arch/arm64/kernel/entry-common.c:637
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585
rcu: rcu_preempt kthread starved for 10502 jiffies! g3797 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:0     pid:16    ppid:2      flags:0x00000008
Call trace:
 __switch_to+0x308/0x598 arch/arm64/kernel/process.c:553
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0xef4/0x1d44 kernel/sched/core.c:6561
 schedule+0xc4/0x170 kernel/sched/core.c:6637
 schedule_timeout+0x1d8/0x344 kernel/time/timer.c:1965
 rcu_gp_fqs_loop+0x2cc/0x1538 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0xc0/0x308 kernel/rcu/tree.c:1905
 kthread+0x250/0x2d8 kernel/kthread.c:376
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:864
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 PID: 4326 Comm: syz-executor916 Not tainted 6.1.132-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline]
pc : _raw_spin_unlock_irq+0x44/0x90 kernel/locking/spinlock.c:202
lr : __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:159 [inline]
lr : _raw_spin_unlock_irq+0x3c/0x90 kernel/locking/spinlock.c:202
sp : ffff8000213679c0
x29: ffff8000213679c0 x28: ffff0000d9b49718 x27: ffff800021367d60
x26: 1ffff0000426cf54 x25: dfff800000000000 x24: 1fffe0001b3692e3
x23: 0000000000000021 x22: 0000000000000020 x21: 0000ffff9cc86b20
x20: ffff0000d987d340 x19: ffff0000d9b49280 x18: 1fffe0001924b5fc
x17: 0000000000000000 x16: ffff800008302888 x15: 0000000000000000
x14: 0000000000000001 x13: 0000000000000000 x12: 0000000000000003
x11: 0000000000ff0100 x10: 0000000000000003 x9 : 0000000000000000
x8 : 00000000000000e0 x7 : 0000000018000004 x6 : 0000ffff9cc86b20
x5 : ffff800021367d80 x4 : ffff0000d9b49738 x3 : 0000000000000000
x2 : ffff8000213678e0 x1 : ffff80001248d5c0 x0 : ffff80019e26e000
Call trace:
 arch_local_irq_enable arch/arm64/include/asm/irqflags.h:35 [inline]
 __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:159 [inline]
 _raw_spin_unlock_irq+0x44/0x90 kernel/locking/spinlock.c:202
 spin_unlock_irq include/linux/spinlock.h:401 [inline]
 get_signal+0x1258/0x1528 kernel/signal.c:2874
 do_signal arch/arm64/kernel/signal.c:1076 [inline]
 do_notify_resume+0x2f8/0x2cb8 arch/arm64/kernel/signal.c:1129
 prepare_exit_to_user_mode arch/arm64/kernel/entry-common.c:137 [inline]
 exit_to_user_mode arch/arm64/kernel/entry-common.c:142 [inline]
 el0_svc+0x9c/0x168 arch/arm64/kernel/entry-common.c:638
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
 el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585