rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P44/1:b..l (detected by 1, t=10502 jiffies, g=172805, q=16) task:kworker/u4:2 state:R running task stack:26064 pid: 44 ppid: 2 flags:0x00004000 Workqueue: bat_events batadv_nc_worker Call Trace: context_switch kernel/sched/core.c:4986 [inline] __schedule+0xab2/0x4f00 kernel/sched/core.c:6296 preempt_schedule_irq+0x4e/0x90 kernel/sched/core.c:6711 irqentry_exit+0x31/0x80 kernel/entry/common.c:425 asm_sysvec_reschedule_ipi+0x12/0x20 arch/x86/include/asm/idtentry.h:643 RIP: 0010:lock_acquire+0x1ef/0x510 kernel/locking/lockdep.c:5607 Code: 8c a6 7e 83 f8 01 0f 85 b4 02 00 00 9c 58 f6 c4 02 0f 85 9f 02 00 00 48 83 7c 24 08 00 74 01 fb 48 b8 00 00 00 00 00 fc ff df <48> 01 c3 48 c7 03 00 00 00 00 48 c7 43 08 00 00 00 00 48 8b 84 24 RSP: 0018:ffffc90001157ba0 EFLAGS: 00000206 RAX: dffffc0000000000 RBX: 1ffff9200022af76 RCX: d2b54abcc85de099 RDX: 1ffff110023e4593 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8ffb9a47 R10: fffffbfff1ff7348 R11: 0000000000000000 R12: 0000000000000002 R13: 0000000000000000 R14: ffffffff8bb829a0 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:268 [inline] rcu_read_lock include/linux/rcupdate.h:694 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline] batadv_nc_worker+0x12d/0xfa0 net/batman-adv/network-coding.c:719 process_one_work+0x9ac/0x1650 kernel/workqueue.c:2307 worker_thread+0x657/0x1110 kernel/workqueue.c:2454 kthread+0x405/0x4f0 kernel/kthread.c:327 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 rcu: rcu_preempt kthread starved for 10502 jiffies! g172805 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:28936 pid: 14 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:4986 [inline] __schedule+0xab2/0x4f00 kernel/sched/core.c:6296 schedule+0xd2/0x260 kernel/sched/core.c:6369 schedule_timeout+0x14a/0x2a0 kernel/time/timer.c:1881 rcu_gp_fqs_loop+0x186/0x810 kernel/rcu/tree.c:1963 rcu_gp_kthread+0x1de/0x320 kernel/rcu/tree.c:2136 kthread+0x405/0x4f0 kernel/kthread.c:327 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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 20883 Comm: syz-executor.5 Not tainted 5.16.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__kasan_check_read+0x0/0x10 mm/kasan/shadow.c:31 Code: 8b e8 b6 23 49 07 48 85 db 0f 85 e0 7a 4a 07 48 83 c4 60 5b 5d 41 5c 41 5d c3 c3 e9 e0 7b 4a 07 cc cc cc cc cc cc cc cc cc cc <48> 8b 0c 24 89 f6 31 d2 e9 f3 f9 ff ff 0f 1f 00 48 8b 0c 24 89 f6 RSP: 0018:ffffc90000007a08 EFLAGS: 00000046 RAX: 0000000000000000 RBX: 1ffff92000000f44 RCX: 0000000000000002 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8d934210 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff819646d9 R11: 0000000000000000 R12: 0000000000000002 R13: 0000000000000000 R14: ffffffff8bb829a0 R15: 0000000000000000 FS: 00007f3298dcf700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f5587b25fc8 CR3: 0000000027fbb000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: instrument_atomic_read include/linux/instrumented.h:71 [inline] test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline] cpumask_test_cpu include/linux/cpumask.h:344 [inline] cpu_online include/linux/cpumask.h:895 [inline] trace_lock_acquire include/trace/events/lock.h:13 [inline] lock_acquire+0xb8/0x510 kernel/locking/lockdep.c:5610 rcu_lock_acquire include/linux/rcupdate.h:268 [inline] rcu_read_lock include/linux/rcupdate.h:694 [inline] __perf_event_output kernel/events/core.c:7506 [inline] perf_event_output_forward+0xa5/0x280 kernel/events/core.c:7528 __perf_event_overflow+0x13c/0x3d0 kernel/events/core.c:9228 perf_swevent_hrtimer+0x37c/0x3f0 kernel/events/core.c:10621 __run_hrtimer kernel/time/hrtimer.c:1685 [inline] __hrtimer_run_queues+0x1c0/0xe50 kernel/time/hrtimer.c:1749 hrtimer_interrupt+0x31c/0x790 kernel/time/hrtimer.c:1811 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1086 [inline] __sysvec_apic_timer_interrupt+0x146/0x530 arch/x86/kernel/apic/apic.c:1103 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1097 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638 RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:160 [inline] RIP: 0010:_raw_spin_unlock_irq+0x25/0x40 kernel/locking/spinlock.c:202 Code: 0f 1f 44 00 00 55 48 8b 74 24 08 48 89 fd 48 83 c7 18 e8 2e 22 0f f8 48 89 ef e8 e6 97 0f f8 e8 01 7e 30 f8 fb bf 01 00 00 00 86 52 02 f8 65 8b 05 bf ac b5 76 85 c0 74 02 5d c3 e8 2b 82 b3 RSP: 0018:ffffc90010c874c0 EFLAGS: 00000206 RAX: 0000000000efd163 RBX: dffffc0000000000 RCX: 1ffffffff1ff7cee RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001 RBP: ffff8881400914f0 R08: 0000000000000001 R09: ffffffff8ffb9a4f R10: 0000000000000001 R11: 0000000000000001 R12: 1ffffffff1701e30 R13: ffff88801d5be0c0 R14: ffff8881400914f0 R15: ffffc900108cf590 rwsem_down_write_slowpath+0x576/0x1110 kernel/locking/rwsem.c:1118 __down_write_common kernel/locking/rwsem.c:1259 [inline] __down_write_common kernel/locking/rwsem.c:1256 [inline] __down_write kernel/locking/rwsem.c:1268 [inline] down_write+0x135/0x150 kernel/locking/rwsem.c:1515 kernfs_activate+0x87/0x240 fs/kernfs/dir.c:1309 kernfs_add_one+0x3c6/0x550 fs/kernfs/dir.c:767 __kernfs_create_file+0x29c/0x350 fs/kernfs/file.c:1016 sysfs_add_file_mode_ns+0x20f/0x3f0 fs/sysfs/file.c:294 create_files fs/sysfs/group.c:64 [inline] internal_create_group+0x322/0xb10 fs/sysfs/group.c:148 internal_create_groups.part.0+0x90/0x140 fs/sysfs/group.c:188 internal_create_groups fs/sysfs/group.c:184 [inline] sysfs_create_groups+0x25/0x50 fs/sysfs/group.c:214 create_dir lib/kobject.c:100 [inline] kobject_add_internal+0x583/0xa60 lib/kobject.c:255 kobject_add_varg lib/kobject.c:390 [inline] kobject_init_and_add+0x101/0x160 lib/kobject.c:473 ext4_register_sysfs+0xb5/0x360 fs/ext4/sysfs.c:526 __ext4_fill_super fs/ext4/super.c:5398 [inline] ext4_fill_super+0xa838/0xe7d0 fs/ext4/super.c:5558 get_tree_bdev+0x440/0x760 fs/super.c:1295 vfs_get_tree+0x89/0x2f0 fs/super.c:1500 do_new_mount fs/namespace.c:2994 [inline] path_mount+0x1320/0x1fa0 fs/namespace.c:3324 do_mount fs/namespace.c:3337 [inline] __do_sys_mount fs/namespace.c:3545 [inline] __se_sys_mount fs/namespace.c:3522 [inline] __x64_sys_mount+0x27f/0x300 fs/namespace.c:3522 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f329a47c51a Code: 48 c7 c2 bc ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb d2 e8 b8 04 00 00 0f 1f 84 00 00 00 00 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f3298dcef88 EFLAGS: 00000206 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 0000000020000200 RCX: 00007f329a47c51a RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007f3298dcefe0 RBP: 00007f3298dcf020 R08: 00007f3298dcf020 R09: 0000000020000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000020000000 R13: 0000000020000100 R14: 00007f3298dcefe0 R15: 00000000200000c0 ---------------- Code disassembly (best guess): 0: 8c a6 7e 83 f8 01 mov %fs,0x1f8837e(%rsi) 6: 0f 85 b4 02 00 00 jne 0x2c0 c: 9c pushfq d: 58 pop %rax e: f6 c4 02 test $0x2,%ah 11: 0f 85 9f 02 00 00 jne 0x2b6 17: 48 83 7c 24 08 00 cmpq $0x0,0x8(%rsp) 1d: 74 01 je 0x20 1f: fb sti 20: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 27: fc ff df * 2a: 48 01 c3 add %rax,%rbx <-- trapping instruction 2d: 48 c7 03 00 00 00 00 movq $0x0,(%rbx) 34: 48 c7 43 08 00 00 00 movq $0x0,0x8(%rbx) 3b: 00 3c: 48 rex.W 3d: 8b .byte 0x8b 3e: 84 .byte 0x84 3f: 24 .byte 0x24