rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6560/1:b..l P7054/1:b..l P6591/1:b..l P7049/1:b..l rcu: (detected by 1, t=10502 jiffies, g=30325, q=1367 ncpus=2) task:syz.4.332 state:R running task stack:24528 pid:7049 tgid:7043 ppid:6594 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5188 [inline] __schedule+0x1800/0x4a60 kernel/sched/core.c:6529 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:6851 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:ma_data_end lib/maple_tree.c:1419 [inline] RIP: 0010:mtree_range_walk+0x1ab/0x8e0 lib/maple_tree.c:2771 Code: 8d 45 ff 89 44 24 04 0f b6 c0 49 89 ce 48 8d 1c c1 48 89 d8 48 c1 e8 03 42 80 3c 20 00 74 08 48 89 df e8 78 59 50 f6 48 8b 1b <31> ff 48 89 de e8 db 24 e9 f5 48 85 db 0f 85 8e 04 00 00 e8 ed 1f RSP: 0018:ffffc900041a76d8 EFLAGS: 00000246 RAX: 1ffff110054a180f RBX: 00007fdc34c00fff RCX: ffff88802a50c008 RDX: ffffc9000ff29000 RSI: 0000000000009c6e RDI: 0000000000009c6f RBP: 000000000000000f R08: 0000000000000005 R09: ffffffff8baa55b2 R10: 0000000000000003 R11: ffff8880232fda00 R12: dffffc0000000000 R13: ffff88802a50c000 R14: ffff88802a50c008 R15: ffffc900041a7828 mas_state_walk lib/maple_tree.c:3678 [inline] mt_find+0x311/0x850 lib/maple_tree.c:6932 find_vma+0xf9/0x170 mm/mmap.c:2019 lock_mm_and_find_vma+0x5f/0x2f0 mm/memory.c:5933 do_user_addr_fault arch/x86/mm/fault.c:1361 [inline] handle_page_fault arch/x86/mm/fault.c:1481 [inline] exc_page_fault+0x1bf/0x8c0 arch/x86/mm/fault.c:1539 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 RIP: 0010:copy_user_generic arch/x86/include/asm/uaccess_64.h:110 [inline] RIP: 0010:raw_copy_to_user arch/x86/include/asm/uaccess_64.h:131 [inline] RIP: 0010:_inline_copy_to_user include/linux/uaccess.h:181 [inline] RIP: 0010:_copy_to_user+0x81/0xb0 lib/usercopy.c:26 Code: fc 4c 89 f0 4c 01 e0 78 3b 4c 39 f0 72 36 e8 f6 32 e3 fc 4c 89 ff 44 89 e6 e8 cb 6e 4a fd 0f 01 cb 4c 89 e1 4c 89 fe 4c 89 f7 a4 0f 1f 00 49 89 cc 0f 01 ca 4c 89 e0 5b 41 5c 41 5e 41 5f e9 RSP: 0018:ffffc900041a7ad8 EFLAGS: 00050256 RAX: ffffffff84b04301 RBX: 000000002003c040 RCX: 0000000000000040 RDX: 0000000000000000 RSI: ffffc900041a7b60 RDI: 000000002003c000 RBP: ffffc900041a7c10 R08: ffffc900041a7b9f R09: 1ffff92000834f73 R10: dffffc0000000000 R11: fffff52000834f74 R12: 0000000000000040 R13: 0000000000008580 R14: 000000002003c000 R15: ffffc900041a7b60 copy_to_user include/linux/uaccess.h:209 [inline] rng_dev_read+0x3be/0x6d0 drivers/char/hw_random/core.c:251 do_loop_readv_writev fs/read_write.c:761 [inline] vfs_readv+0x6c4/0xa90 fs/read_write.c:934 do_preadv fs/read_write.c:1049 [inline] __do_sys_preadv fs/read_write.c:1099 [inline] __se_sys_preadv fs/read_write.c:1094 [inline] __x64_sys_preadv+0x1c7/0x2d0 fs/read_write.c:1094 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fdc367779f9 RSP: 002b:00007fdc37478048 EFLAGS: 00000246 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 00007fdc36906058 RCX: 00007fdc367779f9 RDX: 0000000000000001 RSI: 0000000020000240 RDI: 0000000000000003 RBP: 00007fdc367e58ee R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000006e R14: 00007fdc36906058 R15: 00007ffd8eee2238 task:syz-executor state:R running task stack:20992 pid:6591 tgid:6591 ppid:6580 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5188 [inline] __schedule+0x1800/0x4a60 kernel/sched/core.c:6529 preempt_schedule_notrace+0x100/0x140 kernel/sched/core.c:6801 preempt_schedule_notrace_thunk+0x1a/0x30 arch/x86/entry/thunk.S:13 rcu_is_watching+0x7e/0xb0 kernel/rcu/tree.c:727 trace_lock_release include/trace/events/lock.h:69 [inline] lock_release+0xbf/0xa30 kernel/locking/lockdep.c:5770 rcu_lock_release include/linux/rcupdate.h:336 [inline] rcu_read_unlock include/linux/rcupdate.h:869 [inline] kernfs_should_drain_open_files+0x275/0x320 fs/kernfs/file.c:787 kernfs_drain+0x289/0x6d0 fs/kernfs/dir.c:494 __kernfs_remove+0x400/0x870 fs/kernfs/dir.c:1486 kernfs_remove_by_name_ns+0xdc/0x160 fs/kernfs/dir.c:1694 kernfs_remove_by_name include/linux/kernfs.h:625 [inline] remove_files fs/sysfs/group.c:28 [inline] sysfs_remove_group+0xfe/0x2c0 fs/sysfs/group.c:319 sysfs_remove_groups+0x54/0xb0 fs/sysfs/group.c:343 device_remove_groups drivers/base/core.c:2833 [inline] device_remove_attrs+0x23a/0x290 drivers/base/core.c:2969 device_del+0x572/0x9b0 drivers/base/core.c:3867 unregister_netdevice_many_notify+0x1709/0x1c40 net/core/dev.c:11378 unregister_netdevice_many net/core/dev.c:11406 [inline] unregister_netdevice_queue+0x303/0x370 net/core/dev.c:11281 unregister_netdevice include/linux/netdevice.h:3129 [inline] __tun_detach+0x6b6/0x1600 drivers/net/tun.c:685 tun_detach drivers/net/tun.c:701 [inline] tun_chr_close+0x108/0x1b0 drivers/net/tun.c:3510 __fput+0x24c/0x8a0 fs/file_table.c:422 task_work_run+0x251/0x310 kernel/task_work.c:228 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0xa2f/0x27f0 kernel/exit.c:882 do_group_exit+0x207/0x2c0 kernel/exit.c:1031 __do_sys_exit_group kernel/exit.c:1042 [inline] __se_sys_exit_group kernel/exit.c:1040 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1040 x64_sys_call+0x2634/0x2640 arch/x86/include/generated/asm/syscalls_64.h:232 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f9ca3d779f9 RSP: 002b:00007ffcdf6696a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007f9ca3de57fe RCX: 00007f9ca3d779f9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 0000000000000016 R08: 00007ffcdf667446 R09: 00007ffcdf66a960 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffcdf66a960 R13: 00007f9ca3de578c R14: 000055555feb64a8 R15: 00007ffcdf66dc00 task:syz.0.334 state:R running task stack:24672 pid:7054 tgid:7054 ppid:6587 flags:0x00000000 Call Trace: context_switch kernel/sched/core.c:5188 [inline] __schedule+0x1800/0x4a60 kernel/sched/core.c:6529 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:6851 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__sanitizer_cov_trace_switch+0x83/0x120 Code: 24 e9 aa 00 00 00 41 b8 01 00 00 00 4d 85 d2 75 14 e9 9a 00 00 00 41 b8 05 00 00 00 4d 85 d2 0f 84 8b 00 00 00 4c 8b 4c 24 20 <65> 4c 8b 1c 25 40 d7 03 00 31 d2 eb 08 48 ff c2 49 39 d2 74 71 4c RSP: 0000:ffffc90004737cb0 EFLAGS: 00000206 RAX: 0000000000000003 RBX: ffff888018ac561c RCX: ffffc90004737e40 RDX: 0000000000000000 RSI: ffffffff8ffe7ff0 RDI: 0000000000000003 RBP: 0000000000000003 R08: 0000000000000005 R09: ffffffff8baa55b2 R10: 0000000000000003 R11: ffff88802240bc00 R12: dffffc0000000000 R13: ffff888018ac5600 R14: 1ffff920008e6fcf R15: ffffc90004737e48 ma_pivots lib/maple_tree.c:654 [inline] mtree_range_walk+0xf2/0x8e0 lib/maple_tree.c:2770 mas_state_walk lib/maple_tree.c:3678 [inline] mas_walk+0x83/0x280 lib/maple_tree.c:4906 lock_vma_under_rcu+0x231/0x6e0 mm/memory.c:5995 do_user_addr_fault arch/x86/mm/fault.c:1329 [inline] handle_page_fault arch/x86/mm/fault.c:1481 [inline] exc_page_fault+0x17b/0x8c0 arch/x86/mm/fault.c:1539 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 RIP: 0033:0x7f43e643883c RSP: 002b:00007ffd726b64a8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 00007f43e7235720 RCX: 0000000000000000 RDX: 000000000000065a RSI: ffffffff8136665a RDI: 0000000000000001 RBP: 0000000000000000 R08: 00007f43e66f0000 R09: 00007f43e66f2000 R10: 000000008136665e R11: 0000000000000001 R12: ffffffff8136633a R13: 00007f43e67060f0 R14: 0000000000000008 R15: 0000000000000021 task:kworker/u8:16 state:R running task stack:24624 pid:6560 tgid:6560 ppid:2 flags:0x00004000 Workqueue: bat_events batadv_nc_worker Call Trace: context_switch kernel/sched/core.c:5188 [inline] __schedule+0x1800/0x4a60 kernel/sched/core.c:6529 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:6851 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:lock_acquire+0x264/0x550 kernel/locking/lockdep.c:5763 Code: 2b 00 74 08 4c 89 f7 e8 2a f3 8a 00 f6 44 24 61 02 0f 85 85 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25 RSP: 0018:ffffc90002edf9e0 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 1ffff920005dbf48 RCX: ffc60d52d5253b00 RDX: dffffc0000000000 RSI: ffffffff8c0ae6e0 RDI: ffffffff8c605cc0 RBP: ffffc90002edfb40 R08: ffffffff9372a807 R09: 1ffffffff26e5500 R10: dffffc0000000000 R11: fffffbfff26e5501 R12: 1ffff920005dbf44 R13: dffffc0000000000 R14: ffffc90002edfa40 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:326 [inline] rcu_read_lock include/linux/rcupdate.h:838 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline] batadv_nc_worker+0xec/0x610 net/batman-adv/network-coding.c:719 process_one_work kernel/workqueue.c:3231 [inline] process_scheduled_works+0xa2e/0x1830 kernel/workqueue.c:3312 worker_thread+0x86d/0xd40 kernel/workqueue.c:3390 kthread+0x2f2/0x390 kernel/kthread.c:389 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 rcu: rcu_preempt kthread starved for 10533 jiffies! g30325 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:26448 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5188 [inline] __schedule+0x1800/0x4a60 kernel/sched/core.c:6529 __schedule_loop kernel/sched/core.c:6606 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6621 schedule_timeout+0x1be/0x310 kernel/time/timer.c:2581 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2034 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2236 kthread+0x2f2/0x390 kernel/kthread.c:389 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 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:48 [inline] NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:106 [inline] NMI backtrace for cpu 0 skipped: idling at acpi_safe_halt+0x21/0x30 drivers/acpi/processor_idle.c:111