rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: (detected by 0, t=10502 jiffies, g=6621, q=48) rcu: All QSes seen, last rcu_preempt kthread activity 10503 (4294954113-4294943610), jiffies_till_next_fqs=1, root ->qsmask 0x0 syz-executor.0 R running task 28696 8334 8313 0x0000400a Call Trace: sched_show_task+0x40f/0x560 kernel/sched/core.c:5954 print_other_cpu_stall kernel/rcu/tree_stall.h:410 [inline] check_cpu_stall kernel/rcu/tree_stall.h:538 [inline] rcu_pending kernel/rcu/tree.c:2827 [inline] rcu_sched_clock_irq+0x1861/0x1ad0 kernel/rcu/tree.c:2271 update_process_times+0x12d/0x180 kernel/time/timer.c:1726 tick_sched_handle kernel/time/tick-sched.c:167 [inline] tick_sched_timer+0x263/0x420 kernel/time/tick-sched.c:1310 __run_hrtimer kernel/time/hrtimer.c:1514 [inline] __hrtimer_run_queues+0x403/0x840 kernel/time/hrtimer.c:1576 hrtimer_interrupt+0x38c/0xda0 kernel/time/hrtimer.c:1638 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline] smp_apic_timer_interrupt+0x109/0x280 arch/x86/kernel/apic/apic.c:1135 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:829 RIP: 0010:__memcg_kmem_uncharge+0xe/0x2e0 mm/memcontrol.c:2909 Code: c3 08 02 00 00 48 89 df 4c 89 f6 e8 dc 7d ff ff 5b 41 5e 5d c3 0f 1f 80 00 00 00 00 55 48 89 e5 41 57 41 56 41 55 41 54 53 50 <89> f3 49 89 fc 48 b8 00 00 00 00 00 fc ff df 4c 8d 77 38 4d 89 f5 RSP: 0018:ffffc900026c77a0 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: ffffffff81486ea4 RBX: ffffea000252e280 RCX: 0000000000040000 RDX: ffffc90001f39000 RSI: 0000000000000000 RDI: ffffea000252e280 RBP: ffffc900026c77d0 R08: dffffc0000000000 R09: fffffbfff120248a R10: fffffbfff120248a R11: 0000000000000000 R12: ffff8880908a1b20 R13: dffffc0000000000 R14: 1ffff11012114364 R15: ffff8880a81ed5e8 memcg_kmem_uncharge include/linux/memcontrol.h:1402 [inline] free_thread_stack+0x12e/0x590 kernel/fork.c:284 release_task_stack kernel/fork.c:440 [inline] put_task_stack+0xa3/0x130 kernel/fork.c:451 finish_task_switch+0x3f1/0x550 kernel/sched/core.c:3256 context_switch kernel/sched/core.c:3388 [inline] __schedule+0x9a8/0xcc0 kernel/sched/core.c:4081 preempt_schedule_common kernel/sched/core.c:4236 [inline] preempt_schedule+0xdb/0x120 kernel/sched/core.c:4261 ___preempt_schedule+0x16/0x18 arch/x86/entry/thunk_64.S:50 vprintk_emit+0x36d/0x3a0 kernel/printk/printk.c:1997 vprintk_default+0x28/0x30 kernel/printk/printk.c:2023 vprintk_func+0x158/0x170 kernel/printk/printk_safe.c:386 printk+0x62/0x8d kernel/printk/printk.c:2056 ceph_parse_ips+0x9a2/0x9f0 net/ceph/messenger.c:2007 ceph_parse_options+0x29d/0x14c0 net/ceph/ceph_common.c:395 parse_mount_options fs/ceph/super.c:531 [inline] ceph_mount+0x3c7/0x15c0 fs/ceph/super.c:1092 legacy_get_tree+0xf9/0x1a0 fs/fs_context.c:647 vfs_get_tree+0x8b/0x2a0 fs/super.c:1545 do_new_mount fs/namespace.c:2822 [inline] do_mount+0x16bb/0x24f0 fs/namespace.c:3142 ksys_mount+0xcc/0x100 fs/namespace.c:3351 __do_sys_mount fs/namespace.c:3365 [inline] __se_sys_mount fs/namespace.c:3362 [inline] __x64_sys_mount+0xbf/0xd0 fs/namespace.c:3362 do_syscall_64+0xf7/0x1c0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45a679 Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fb1e21eac78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 000000000045a679 RDX: 0000000020000140 RSI: 00000000200000c0 RDI: 0000000020000040 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb1e21eb6d4 R13: 00000000004c7a16 R14: 00000000004de750 R15: 00000000ffffffff rcu: rcu_preempt kthread starved for 10543 jiffies! g6621 f0x2 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29104 10 2 0x80004000 Call Trace: context_switch kernel/sched/core.c:3385 [inline] __schedule+0x9a0/0xcc0 kernel/sched/core.c:4081 schedule+0x181/0x210 kernel/sched/core.c:4155 schedule_timeout+0x14f/0x240 kernel/time/timer.c:1895 rcu_gp_fqs_loop kernel/rcu/tree.c:1661 [inline] rcu_gp_kthread+0xed8/0x1770 kernel/rcu/tree.c:1821 kthread+0x332/0x350 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352