rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6585/1:b..l P6590/1:b..l (detected by 0, t=10502 jiffies, g=23005, q=15 ncpus=2) task:syz.0.592 state:R running task stack:25312 pid:6590 ppid:4274 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6730 preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6754 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0xf6/0x100 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] __wake_up_common_lock kernel/sched/wait.c:140 [inline] __wake_up_sync_key+0x11b/0x180 kernel/sched/wait.c:208 sock_def_readable+0x15b/0x280 net/core/sock.c:3313 __netlink_sendskb net/netlink/af_netlink.c:1264 [inline] netlink_broadcast_deliver net/netlink/af_netlink.c:1399 [inline] do_one_broadcast net/netlink/af_netlink.c:1479 [inline] netlink_broadcast+0xcea/0x10d0 net/netlink/af_netlink.c:1519 uevent_net_broadcast_untagged lib/kobject_uevent.c:331 [inline] kobject_uevent_net_broadcast+0x364/0x530 lib/kobject_uevent.c:409 kobject_uevent_env+0x54c/0x8a0 lib/kobject_uevent.c:608 loop_configure+0xece/0x1230 drivers/block/loop.c:1109 lo_ioctl+0x82b/0x1bf0 drivers/block/loop.c:-1 blkdev_ioctl+0x37b/0x700 block/ioctl.c:620 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:870 [inline] __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fa61f58f34b RSP: 002b:00007fa6203badc0 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007fa61f58f34b RDX: 0000000000000003 RSI: 0000000000004c00 RDI: 0000000000000004 RBP: 0000000000000000 R08: 0000000000000000 R09: 00000000000004f6 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 R13: 00007fa6203baef0 R14: 00007fa6203baeb0 R15: 00007fa6153f7000 task:syz.3.588 state:R running task stack:24160 pid:6585 ppid:4275 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873 irqentry_exit+0x63/0x70 kernel/entry/common.c:439 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691 RIP: 0010:lock_is_held_type+0x13a/0x190 kernel/locking/lockdep.c:5710 Code: 75 40 48 c7 04 24 00 00 00 00 9c 8f 04 24 f7 04 24 00 02 00 00 75 46 41 f7 c5 00 02 00 00 74 01 fb 65 48 8b 04 25 28 00 00 00 <48> 3b 44 24 08 75 3c 89 e8 48 83 c4 10 5b 41 5c 41 5d 41 5e 41 5f RSP: 0018:ffffc90004a0f730 EFLAGS: 00000206 RAX: 7931ec8a8e5e3800 RBX: ffff888029c8bb80 RCX: 7931ec8a8e5e3800 RDX: ffff888029c8bb80 RSI: ffffffff8a8c1700 RDI: ffffffff8adef760 RBP: 0000000000000001 R08: ffff888029c8bb80 R09: 0000000000000002 R10: 0000000000000003 R11: 0000000000000002 R12: 0000000000000001 R13: 0000000000000246 R14: ffffffff8cb2aca0 R15: ffff888029c8c688 xa_entry include/linux/xarray.h:1198 [inline] xas_descend+0x129/0x490 lib/xarray.c:204 xas_load lib/xarray.c:242 [inline] xas_find+0x1e0/0xab0 lib/xarray.c:1252 first_map_page mm/filemap.c:3418 [inline] filemap_map_pages+0x245/0x10d0 mm/filemap.c:3445 do_fault_around mm/memory.c:4600 [inline] do_read_fault mm/memory.c:4626 [inline] do_fault mm/memory.c:4760 [inline] handle_pte_fault mm/memory.c:5031 [inline] __handle_mm_fault mm/memory.c:5173 [inline] handle_mm_fault+0x287e/0x3e60 mm/memory.c:5294 faultin_page mm/gup.c:1026 [inline] __get_user_pages+0x3ff/0xeb0 mm/gup.c:1250 populate_vma_page_range+0x214/0x2b0 mm/gup.c:1607 __mm_populate+0x248/0x370 mm/gup.c:1721 mm_populate include/linux/mm.h:2891 [inline] vm_mmap_pgoff+0x203/0x2b0 mm/util.c:525 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fdd12f8f749 RSP: 002b:00007fdd111f6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007fdd131e6180 RCX: 00007fdd12f8f749 RDX: b635773f06ebbeee RSI: 0000000000b36000 RDI: 0000200000000000 RBP: 00007fdd13013f91 R08: ffffffffffffffff R09: 0000000000000000 R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fdd131e6218 R14: 00007fdd131e6180 R15: 00007ffd4d22c778 rcu: rcu_preempt kthread starved for 10560 jiffies! g23005 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:27008 pid:16 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x10ec/0x40b0 kernel/sched/core.c:6561 schedule+0xb9/0x180 kernel/sched/core.c:6637 schedule_timeout+0x15c/0x280 kernel/time/timer.c:2167 rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706 rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905 kthread+0x29d/0x330 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline] NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline] NMI backtrace for cpu 1 skipped: idling at default_idle+0xb/0x10 arch/x86/kernel/process.c:741