bisecting fixing commit since 94f2630b18975bb56eee5d1a36371db967643479 building syzkaller on 2274ad39c8bee8efda31dc31ec8933d5624e8fe4 testing commit 94f2630b18975bb56eee5d1a36371db967643479 with gcc (GCC) 8.1.0 kernel signature: e67bedab80feb6eae942909297ead7da3051bf734632677c16edfb38c36f9089 run #0: crashed: INFO: rcu detected stall in corrupted run #1: crashed: INFO: rcu detected stall in corrupted run #2: crashed: INFO: rcu detected stall in kvm_vcpu_ioctl run #3: crashed: INFO: rcu detected stall in corrupted run #4: crashed: INFO: rcu detected stall in corrupted run #5: crashed: INFO: rcu detected stall in corrupted run #6: crashed: INFO: rcu detected stall in corrupted run #7: crashed: INFO: rcu detected stall in corrupted run #8: crashed: INFO: rcu detected stall in kvm_vcpu_ioctl run #9: crashed: INFO: rcu detected stall in corrupted testing current HEAD 8f3d9f354286745c751374f5f1fcafee6b3f3136 testing commit 8f3d9f354286745c751374f5f1fcafee6b3f3136 with gcc (GCC) 8.1.0 kernel signature: 1dfe1e8ef17f239f1e3f68532894a2a1d6fd722a393251cca03dcf2b36623677 run #0: crashed: INFO: rcu detected stall in kvm_vcpu_ioctl run #1: crashed: INFO: rcu detected stall in corrupted run #2: crashed: INFO: rcu detected stall in kvm_vcpu_ioctl run #3: crashed: INFO: rcu detected stall in corrupted run #4: crashed: INFO: rcu detected stall in kvm_vcpu_ioctl run #5: crashed: INFO: rcu detected stall in corrupted run #6: crashed: INFO: rcu detected stall in corrupted run #7: crashed: INFO: rcu detected stall in kvm_vcpu_ioctl run #8: crashed: INFO: rcu detected stall in corrupted run #9: boot failed: can't ssh into the instance revisions tested: 2, total time: 29m53.779268071s (build: 12m38.194277892s, test: 16m19.51266628s) the crash still happens on HEAD commit msg: Linux 5.7-rc1 crash: INFO: rcu detected stall in corrupted rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P470 (detected by 1, t=10502 jiffies, g=8309, q=287) kworker/u4:6 R running task 23424 470 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_restore arch/x86/include/asm/paravirt.h:759 [inline] RIP: 0010:lock_acquire+0x291/0x9e0 kernel/locking/lockdep.c:4937 Code: ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 62 06 00 00 48 83 3d 2e 9c c0 07 00 0f 84 d1 04 00 00 48 8b bd 48 ff ff ff 57 9d <0f> 1f 44 00 00 48 b8 00 00 00 00 00 fc ff df 48 01 c3 c7 03 00 00 RSP: 0018:ffffc90002887c28 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13 RAX: dffffc0000000000 RBX: 1ffff92000510f89 RCX: 1ffff92000510f6e RDX: 1ffffffff1228d2c RSI: 0000000000000001 RDI: 0000000000000282 RBP: ffffc90002887cf0 R08: fffffbfff154ad2d R09: fffffbfff154ad2d R10: ffffffff8aa56967 R11: fffffbfff154ad2c R12: ffff8880a8170200 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 10502 jiffies! g8309 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: RCU grace-period kthread stack dump: rcu_preempt R running task 29096 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