syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4305/1:b..l
	(detected by 1, t=10502 jiffies, g=4113, q=318 ncpus=2)
task:syz-executor370 state:R  running task     stack:0     pid:4305  ppid:4300   flags:0x00000004
Call trace:
 __switch_to+0x2f4/0x568 arch/arm64/kernel/process.c:555
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0xdd4/0x1b2c kernel/sched/core.c:6561
 preempt_schedule_irq+0x8c/0x1b8 kernel/sched/core.c:6873
 arm64_preempt_schedule_irq+0x44/0x58 arch/arm64/kernel/entry-common.c:265
 __el1_irq arch/arm64/kernel/entry-common.c:474 [inline]
 el1_interrupt+0x3c/0x54 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
 __preempt_count_add+0x28/0x6c arch/arm64/include/asm/preempt.h:47
 lockdep_enabled kernel/locking/lockdep.c:119 [inline]
 lock_is_held_type+0x34/0x198 kernel/locking/lockdep.c:5698
 lock_is_held include/linux/lockdep.h:283 [inline]
 task_css include/linux/cgroup.h:509 [inline]
 mem_cgroup_from_task+0x64/0x120 mm/memcontrol.c:985
 get_obj_cgroup_from_current+0x268/0x450 mm/memcontrol.c:3023
 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]
 slab_alloc mm/slub.c:3406 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3413 [inline]
 kmem_cache_alloc+0xa8/0x318 mm/slub.c:3422
 vm_area_dup+0x30/0x1c8 kernel/fork.c:467
 dup_mmap kernel/fork.c:646 [inline]
 dup_mm kernel/fork.c:1541 [inline]
 copy_mm+0x7fc/0x11d4 kernel/fork.c:1590
 copy_process+0x1618/0x3670 kernel/fork.c:2351
 kernel_clone+0x1d8/0x8fc kernel/fork.c:2757
 __do_sys_clone kernel/fork.c:2898 [inline]
 __se_sys_clone kernel/fork.c:2866 [inline]
 __arm64_sys_clone+0x140/0x19c kernel/fork.c:2866
 __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+0x58/0x138 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 10501 jiffies! g4113 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:0     pid:16    ppid:2      flags:0x00000008
Call trace:
 __switch_to+0x2f4/0x568 arch/arm64/kernel/process.c:555
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0xdd4/0x1b2c kernel/sched/core.c:6561
 schedule+0xc4/0x170 kernel/sched/core.c:6637
 schedule_timeout+0x180/0x2c8 kernel/time/timer.c:1965
 rcu_gp_fqs_loop+0x2a8/0x134c kernel/rcu/tree.c:1706
 rcu_gp_kthread+0xc0/0x2f8 kernel/rcu/tree.c:1905
 kthread+0x250/0x2d8 kernel/kthread.c:376
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:849
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 PID: 4327 Comm: syz-executor370 Not tainted 6.1.142-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : lock_release+0x4c0/0x910 arch/arm64/include/asm/irqflags.h:-1
lr : lockdep_recursion_finish kernel/locking/lockdep.c:467 [inline]
lr : lock_release+0x488/0x910 kernel/locking/lockdep.c:5684
sp : ffff800020997600
x29: ffff800020997640 x28: ffff800014fd5d00 x27: 0000000000000000
x26: dfff800000000000 x25: 0000000000000000 x24: ffff0000d8795db8
x23: 0000000000000001 x22: 0000000000000000 x21: ffffffffffffffff
x20: ffff0000d8795340 x19: ffff00019f726d00 x18: 0000000000000000
x17: 0000000000000000
 x16: ffff8000082d0f50 x15: 0000ffffefbaf238

x14: 0000000000000000
 x13: 1ffff00002a100b1 x12: 0000000000ff0100
x11: ff0080000a88b400 x10: 0000000000000000 x9 : 0000000000000080
x8 : 0000000000000000 x7 : ffff8000087d2f14 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000001
x2 : 0000000000000008 x1 : ffff800011a8e920 x0 : 0000000000000001
Call trace:
 arch_local_irq_restore arch/arm64/include/asm/irqflags.h:122 [inline]
 lock_release+0x4c0/0x910 kernel/locking/lockdep.c:5685
 __might_fault+0xf0/0x124 mm/memory.c:5852
 restore_sigframe arch/arm64/kernel/signal.c:649 [inline]
 __arm64_sys_rt_sigreturn+0x2a4/0x1e00 arch/arm64/kernel/signal.c:700
 __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+0x58/0x138 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