syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5980/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=7805, q=775 ncpus=2)
task:syz.0.11        state:R  running task     stack:26952 pid:5980  tgid:5975  ppid:5825   task_flags:0x400040 flags:0x00080001
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x1139/0x6150 kernel/sched/core.c:6863
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7190
 irqentry_exit+0x1d8/0x8c0 kernel/entry/common.c:216
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x62/0x330 kernel/locking/lockdep.c:5872
Code: 2f 12 12 83 f8 07 0f 87 a2 02 00 00 89 c0 48 0f a3 05 e2 93 ed 0e 0f 82 74 02 00 00 8b 35 5a c4 ed 0e 85 f6 0f 85 8d 00 00 00 <48> 8b 44 24 30 65 48 2b 05 f9 2e 12 12 0f 85 ad 02 00 00 48 83 c4
RSP: 0018:ffffc900047ff420 EFLAGS: 00000206
RAX: 0000000000000046 RBX: ffffffff8e3c92c0 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff8da9585e RDI: ffffffff8bf21180
RBP: 0000000000000002 R08: 00000000d807b0bd R09: 00000000b985a01d
R10: ffff888079d554b0 R11: 00000000db985a01 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
 rcu_read_lock include/linux/rcupdate.h:867 [inline]
 get_mem_cgroup_from_objcg+0x31/0x210 include/linux/memcontrol.h:516
 obj_cgroup_charge_pages mm/memcontrol.c:2789 [inline]
 obj_cgroup_charge_account+0x281/0x500 mm/memcontrol.c:3094
 __memcg_slab_post_alloc_hook+0x2e3/0x880 mm/memcontrol.c:3180
 memcg_slab_post_alloc_hook mm/slub.c:2338 [inline]
 slab_post_alloc_hook mm/slub.c:4959 [inline]
 slab_alloc_node mm/slub.c:5258 [inline]
 kmem_cache_alloc_lru_noprof+0x581/0x760 mm/slub.c:5277
 __d_alloc+0x35/0xa80 fs/dcache.c:1691
 d_alloc_pseudo+0x1c/0xc0 fs/dcache.c:1822
 alloc_path_pseudo fs/file_table.c:363 [inline]
 alloc_file_pseudo+0xcf/0x230 fs/file_table.c:379
 sock_alloc_file+0x50/0x210 net/socket.c:483
 do_accept+0x240/0x530 net/socket.c:1970
 io_accept+0x259/0x950 io_uring/net.c:1665
 __io_issue_sqe+0xe8/0x7c0 io_uring/io_uring.c:1792
 io_poll_issue+0x12a/0x260 io_uring/io_uring.c:1849
 io_poll_check_events io_uring/poll.c:289 [inline]
 io_poll_task_func+0x402/0xe50 io_uring/poll.c:318
 io_handle_tw_list+0x1a7/0x580 io_uring/io_uring.c:1121
 tctx_task_work_run+0x55/0x2d0 io_uring/io_uring.c:1181
 tctx_task_work+0x7a/0xd0 io_uring/io_uring.c:1199
 task_work_run+0x150/0x240 kernel/task_work.c:233
 get_signal+0x1d0/0x26d0 kernel/signal.c:2807
 arch_do_signal_or_restart+0x8f/0x7e0 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
 exit_to_user_mode_loop+0x8c/0x540 kernel/entry/common.c:75
 __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_work include/linux/entry-common.h:159 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
 do_syscall_64+0x4ee/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc7b078f749
RSP: 002b:00007fc7b160e038 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa
RAX: 0000000000000200 RBX: 00007fc7b09e6180 RCX: 00007fc7b078f749
RDX: 0000000000000000 RSI: 00000000000047f5 RDI: 0000000000000004
RBP: 00007fc7b0813f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc7b09e6218 R14: 00007fc7b09e6180 R15: 00007ffef1c1a098
 </TASK>
rcu: rcu_preempt kthread starved for 10541 jiffies! g7805 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:29104 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00080000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5256 [inline]
 __schedule+0x1139/0x6150 kernel/sched/core.c:6863
 __schedule_loop kernel/sched/core.c:6945 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6960
 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1ea/0xaf0 kernel/rcu/tree.c:2083
 rcu_gp_kthread+0x26d/0x380 kernel/rcu/tree.c:2285
 kthread+0x3c5/0x780 kernel/kthread.c:463
 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82
Code: 66 71 02 e9 93 2f 03 00 0f 1f 00 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 13 23 25 00 fb f4 <c3> cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffffff8e007df8 EFLAGS: 000002c2
RAX: 00000000001c7eb5 RBX: 0000000000000000 RCX: ffffffff8b6536f9
RDX: 0000000000000000 RSI: ffffffff8dabb765 RDI: ffffffff8bf21180
RBP: fffffbfff1c12f50 R08: 0000000000000001 R09: ffffed101708671d
R10: ffff8880b84338eb R11: 00000000ffffffff R12: 0000000000000000
R13: ffffffff8e097a80 R14: ffffffff9086e4d0 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888124968000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000002700 CR3: 000000007f26d000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
 default_idle+0x13/0x20 arch/x86/kernel/process.c:767
 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122
 cpuidle_idle_call kernel/sched/idle.c:191 [inline]
 do_idle+0x38d/0x510 kernel/sched/idle.c:332
 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430
 rest_init+0x16b/0x2b0 init/main.c:757
 start_kernel+0x3f6/0x4d0 init/main.c:1111
 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:310
 x86_64_start_kernel+0x130/0x190 arch/x86/kernel/head64.c:291
 common_startup_64+0x13e/0x148
 </TASK>