rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5800/2:b..l (detected by 1, t=10502 jiffies, g=40677, q=250) task:syz-executor state:R running task stack:21720 pid: 5800 ppid: 5774 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395 preempt_schedule_irq+0xbb/0x160 kernel/sched/core.c:6799 irqentry_exit+0x63/0x70 kernel/entry/common.c:432 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:676 RIP: 0010:lock_acquire+0x208/0x400 kernel/locking/lockdep.c:5627 Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3d 04 f8 0f 85 f1 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:ffffc9000307fb00 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 1bf3c876852a1300 RDX: 0000000000000000 RSI: ffffffff8a2b3a20 RDI: ffffffff8a79f800 RBP: ffffc9000307fc08 R08: dffffc0000000000 R09: 1ffffffff203a618 R10: dffffc0000000000 R11: fffffbfff203a619 R12: ffffffff8c31eaa0 R13: 1ffff9200060ff6c R14: 0000000000000246 R15: dffffc0000000000 rcu_lock_acquire+0x20/0x30 include/linux/rcupdate.h:313 rcu_read_lock include/linux/rcupdate.h:740 [inline] percpu_ref_tryget_many include/linux/percpu-refcount.h:241 [inline] percpu_ref_tryget+0x12/0x150 include/linux/percpu-refcount.h:266 obj_cgroup_tryget include/linux/memcontrol.h:800 [inline] get_obj_cgroup_from_current+0x21a/0x2f0 mm/memcontrol.c:2930 memcg_slab_pre_alloc_hook mm/slab.h:283 [inline] slab_pre_alloc_hook+0x7e/0xc0 mm/slab.h:497 slab_alloc_node mm/slub.c:3139 [inline] slab_alloc mm/slub.c:3233 [inline] kmem_cache_alloc+0x3d/0x290 mm/slub.c:3238 kmem_cache_zalloc include/linux/slab.h:728 [inline] __alloc_file+0x25/0x240 fs/file_table.c:132 alloc_empty_file+0x90/0x180 fs/file_table.c:181 alloc_file+0x5b/0x4f0 fs/file_table.c:223 alloc_file_pseudo+0x180/0x200 fs/file_table.c:263 sock_alloc_file+0xb3/0x240 net/socket.c:464 sock_map_fd net/socket.c:488 [inline] __sys_socket+0x11d/0x170 net/socket.c:1597 __do_sys_socket net/socket.c:1602 [inline] __se_sys_socket net/socket.c:1600 [inline] __x64_sys_socket+0x76/0x80 net/socket.c:1600 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7fb17a46aec7 RSP: 002b:00007ffc21e05058 EFLAGS: 00000206 ORIG_RAX: 0000000000000029 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fb17a46aec7 RDX: 0000000000000006 RSI: 0000000000000001 RDI: 0000000000000002 RBP: 00007ffc21e0575c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 00000000000000aa R13: 000055555905c9f0 R14: 00000000000957e6 R15: 00007ffc21e057b0 rcu: rcu_preempt kthread starved for 10139 jiffies! g40677 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:27760 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_timeout+0x184/0x2d0 kernel/time/timer.c:2117 rcu_gp_fqs_loop+0x2be/0x11d0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0x9b/0x370 kernel/rcu/tree.c:2145 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline] NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline] NMI backtrace for cpu 0 skipped: idling at default_idle+0xb/0x10 arch/x86/kernel/process.c:729