rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P8257 P208 (detected by 0, t=10503 jiffies, g=9153, q=165) syz-executor.1 R running task 27784 8257 7164 0x00000000 Call Trace: context_switch kernel/sched/core.c:3372 [inline] __schedule+0x8ae/0x19c0 kernel/sched/core.c:4088 __sched_text_start+0x8/0x8 spin_unlock include/linux/spinlock.h:393 [inline] fast_dput fs/dcache.c:745 [inline] dput.part.30+0x33d/0xaa0 fs/dcache.c:846 preempt_schedule+0x4d/0x60 kernel/sched/core.c:4269 preempt_schedule_common+0x1f/0xe0 kernel/sched/core.c:4244 dput.part.30+0x2e/0xaa0 fs/dcache.c:840 preempt_schedule+0x4d/0x60 kernel/sched/core.c:4269 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:50 __raw_spin_unlock include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock+0x3a/0x40 kernel/locking/spinlock.c:183 spin_unlock include/linux/spinlock.h:393 [inline] fast_dput fs/dcache.c:745 [inline] dput.part.30+0x33d/0xaa0 fs/dcache.c:846 dput+0x9/0x10 fs/dcache.c:841 path_put fs/namei.c:482 [inline] terminate_walk+0x354/0x490 fs/namei.c:583 path_openat+0x1077/0x2560 fs/namei.c:3347 path_lookupat.isra.39+0x440/0x440 fs/namei.c:2332 mark_held_locks+0x130/0x130 kernel/locking/lockdep.c:3616 find_held_lock+0x36/0x1d0 kernel/locking/lockdep.c:4458 do_filp_open+0x171/0x240 fs/namei.c:3373 lock_downgrade+0x960/0x960 kernel/locking/lockdep.c:4579 may_open_dev+0xc0/0xc0 fs/namei.c:2822 simple_attr_release+0x50/0x50 fs/libfs.c:912 __raw_spin_unlock include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock+0x27/0x40 kernel/locking/spinlock.c:183 spin_unlock include/linux/spinlock.h:393 [inline] __alloc_fd+0x189/0x520 fs/file.c:534 check_object_size include/linux/thread_info.h:119 [inline] strncpy_from_user+0x82/0x350 lib/strncpy_from_user.c:118 do_sys_openat2+0x309/0x590 fs/open.c:1148 file_open_root+0x220/0x220 fs/open.c:994 do_symlinkat+0x11e/0x1e0 fs/namei.c:3971 do_sys_open+0x90/0xe0 fs/open.c:1164 filp_open+0x50/0x50 fs/open.c:1117 __trace_hardirqs_on_caller kernel/locking/lockdep.c:3657 [inline] lockdep_hardirqs_on+0x481/0x620 kernel/locking/lockdep.c:3702 do_syscall_64+0x21/0x630 arch/x86/entry/common.c:288 ksys_open include/linux/syscalls.h:1386 [inline] __do_sys_open fs/open.c:1170 [inline] __se_sys_open fs/open.c:1168 [inline] __x64_sys_open+0x79/0xb0 fs/open.c:1168 do_syscall_64+0xca/0x630 arch/x86/entry/common.c:295 entry_SYSCALL_64_after_hwframe+0x49/0xb3 RIP: 0033:0x414760 Code: 05 48 3d 01 f0 ff ff 0f 83 2d 19 00 00 c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 83 3d 0d 3d 66 00 00 75 14 b8 02 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 04 19 00 00 c3 48 83 ec 08 e8 0a fa ff ff RSP: 002b:00007ffcf6481ec8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002 RAX: ffffffffffffffda RBX: 00007ffcf6481ef4 RCX: 0000000000414760 RDX: 00007ffcf6481efa RSI: 0000000000080001 RDI: 00000000004c048c RBP: 00007ffcf6481ef0 R08: 0000000000000000 R09: 0000000000000004 R10: 0000000000000075 R11: 0000000000000246 R12: 00000000004c048c R13: 00007ffcf6482410 R14: 0000000000000000 R15: 00007ffcf6482420 kworker/u4:4 R running task 25968 208 2 0x80004000 Workqueue: bat_events batadv_nc_worker Call Trace: context_switch kernel/sched/core.c:3372 [inline] __schedule+0x8ae/0x19c0 kernel/sched/core.c:4088 __sched_text_start+0x8/0x8 retint_kernel+0x1b/0x2b __trace_hardirqs_on_caller kernel/locking/lockdep.c:3657 [inline] lockdep_hardirqs_on+0x481/0x620 kernel/locking/lockdep.c:3702 preempt_schedule_irq+0x5e/0x120 kernel/sched/core.c:4345 trace_hardirqs_on+0x28/0x1a0 kernel/trace/trace_preemptirq.c:31 preempt_schedule_irq+0x8b/0x120 kernel/sched/core.c:4346 retint_kernel+0x1b/0x2b RIP: 0010:arch_local_irq_disable arch/x86/include/asm/paravirt.h:764 [inline] RIP: 0010:arch_local_irq_save arch/x86/include/asm/paravirt.h:777 [inline] RIP: 0010:lock_acquire+0x10c/0x9e0 kernel/locking/lockdep.c:4929 Code: 00 0f 85 df 07 00 00 48 83 3d 57 93 a0 07 00 0f 84 0f 06 00 00 9c 58 0f 1f 44 00 00 48 c7 c7 28 6e f4 88 48 89 85 48 ff ff ff <48> b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f RSP: 0018:ffffc90001917c28 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff02 RAX: 0000000000000282 RBX: 1ffff92000322f89 RCX: ffffc90001917cc8 RDX: 1ffffffff11e8dc3 RSI: 0000000000000000 RDI: ffffffff88f46e28 RBP: ffffc90001917cf0 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff89db04c7 R11: fffffbfff13b6098 R12: ffffffff88fb7c40 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu_read_unlock include/linux/rcupdate.h:651 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:411 [inline] batadv_nc_worker+0x174/0x620 net/batman-adv/network-coding.c:718 lock_release+0x960/0x960 kernel/locking/lockdep.c:4689 __kasan_check_read+0x11/0x20 mm/kasan/common.c:72 rcu_lock_acquire include/linux/rcupdate.h:208 [inline] rcu_read_lock include/linux/rcupdate.h:601 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:407 [inline] batadv_nc_worker+0xec/0x620 net/batman-adv/network-coding.c:718 batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:405 [inline] batadv_nc_worker+0xbc/0x620 net/batman-adv/network-coding.c:718 process_one_work+0x893/0x1690 kernel/workqueue.c:2268 lock_acquire+0x209/0x9e0 kernel/locking/lockdep.c:4934 pwq_dec_nr_in_flight+0x2c0/0x2c0 kernel/workqueue.c:1198 worker_thread+0x85/0xb60 kernel/workqueue.c:2414 __kthread_parkme+0x37/0x1c0 kernel/kthread.c:208 kthread+0x354/0x420 kernel/kthread.c:268 process_one_work+0x1690/0x1690 kernel/workqueue.c:2273 kthread_mod_delayed_work+0x190/0x190 kernel/kthread.c:1090 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 rcu: rcu_preempt kthread starved for 10546 jiffies! g9153 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29040 10 2 0x80004000 Call Trace: context_switch kernel/sched/core.c:3372 [inline] __schedule+0x8ae/0x19c0 kernel/sched/core.c:4088 __sched_text_start+0x8/0x8 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline] _raw_spin_unlock_irqrestore+0x7d/0xd0 kernel/locking/spinlock.c:191 __trace_hardirqs_on_caller kernel/locking/lockdep.c:3657 [inline] lockdep_hardirqs_on+0x481/0x620 kernel/locking/lockdep.c:3702 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline] _raw_spin_unlock_irqrestore+0x7d/0xd0 kernel/locking/spinlock.c:191 schedule+0xc3/0x2b0 kernel/sched/core.c:4163 schedule_timeout+0x2bd/0x710 kernel/time/timer.c:1898 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline] _raw_spin_unlock_irqrestore+0x7d/0xd0 kernel/locking/spinlock.c:191 usleep_range+0x130/0x130 kernel/time/timer.c:2093 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:161 [inline] _raw_spin_unlock_irqrestore+0x68/0xd0 kernel/locking/spinlock.c:191 prepare_to_swait_event+0x130/0x390 kernel/sched/swait.c:120 __next_timer_interrupt+0x100/0x100 kernel/time/timer.c:1512 rcu_gp_fqs_loop kernel/rcu/tree.c:1674 [inline] rcu_gp_kthread+0x9da/0x1a40 kernel/rcu/tree.c:1836 atomic_try_cmpxchg include/asm-generic/atomic-instrumented.h:694 [inline] queued_spin_lock include/asm-generic/qspinlock.h:78 [inline] do_raw_spin_lock+0x132/0x2e0 kernel/locking/spinlock_debug.c:113 rcu_barrier+0x4c0/0x4c0 kernel/rcu/tree.c:3366 __kthread_parkme+0x37/0x1c0 kernel/kthread.c:208 test_bit include/asm-generic/bitops/instrumented-non-atomic.h:110 [inline] __kthread_parkme+0xb8/0x1c0 kernel/kthread.c:199 test_bit include/asm-generic/bitops/instrumented-non-atomic.h:110 [inline] test_ti_thread_flag include/linux/thread_info.h:84 [inline] need_resched include/linux/sched.h:1827 [inline] schedule+0xe3/0x2b0 kernel/sched/core.c:4165 kthread+0x354/0x420 kernel/kthread.c:268 rcu_barrier+0x4c0/0x4c0 kernel/rcu/tree.c:3366 kthread_mod_delayed_work+0x190/0x190 kernel/kthread.c:1090 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352