bisecting fixing commit since 7cc2a8ea104820dd9e702202621e8fd4d9f6c8cf
building syzkaller on 510951950dc0ee69cfdaf746061d3dbe31b49fd8
testing commit 7cc2a8ea104820dd9e702202621e8fd4d9f6c8cf with gcc (GCC) 8.1.0
kernel signature: 60fec8638c5eec2fa7ac7f4d906e2d1f00e8532edf0911b4fc7bdae4902084e8
run #0: crashed: INFO: rcu detected stall in tipc_release
run #1: crashed: INFO: rcu detected stall in tipc_release
run #2: crashed: INFO: rcu detected stall in tipc_release
run #3: crashed: INFO: rcu detected stall in tipc_release
run #4: crashed: INFO: rcu detected stall in tipc_release
run #5: crashed: INFO: rcu detected stall in tipc_release
run #6: crashed: INFO: rcu detected stall in tipc_release
run #7: crashed: INFO: rcu detected stall in tipc_release
run #8: crashed: INFO: rcu detected stall in tipc_release
run #9: crashed: INFO: rcu detected stall in corrupted
testing current HEAD 4429f14aeea979b63bcafdcf9f09677fcf8fd475
testing commit 4429f14aeea979b63bcafdcf9f09677fcf8fd475 with gcc (GCC) 8.1.0
kernel signature: 96847c8af594e8e711ebac49217a0c3355ba62057cf29eed71d74795c487a3d0
run #0: crashed: INFO: rcu detected stall in tipc_release
run #1: crashed: INFO: rcu detected stall in corrupted
run #2: crashed: INFO: rcu detected stall in tipc_release
run #3: crashed: INFO: rcu detected stall in tipc_release
run #4: crashed: INFO: rcu detected stall in tipc_release
run #5: crashed: INFO: rcu detected stall in tipc_release
run #6: crashed: INFO: rcu detected stall in tipc_release
run #7: crashed: INFO: rcu detected stall in tipc_release
run #8: crashed: INFO: rcu detected stall in tipc_release
run #9: crashed: INFO: rcu detected stall in tipc_release
revisions tested: 2, total time: 21m53.632249752s (build: 9m30.547113183s, test: 11m46.54081388s)
the crash still happens on HEAD
commit msg: Merge tag 'block-5.10-2020-11-07' of git://git.kernel.dk/linux-block
crash: INFO: rcu detected stall in tipc_release
rcu: INFO: rcu_preempt self-detected stall on CPU
rcu: 	0-...!: (10483 ticks this GP) idle=bd2/1/0x4000000000000000 softirq=14679/14679 fqs=1 
	(t=10501 jiffies g=5773 q=573)
rcu: rcu_preempt kthread starved for 10499 jiffies! g5773 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:14648 pid:   10 ppid:     2 flags:0x00004000
Call Trace:
 context_switch kernel/sched/core.c:3774 [inline]
 __schedule+0x404/0x890 kernel/sched/core.c:4523
 schedule+0x38/0xe0 kernel/sched/core.c:4601
 schedule_timeout+0x1be/0x2e0 kernel/time/timer.c:1871
 rcu_gp_fqs_loop kernel/rcu/tree.c:1925 [inline]
 rcu_gp_kthread+0x707/0xc60 kernel/rcu/tree.c:2099
 kthread+0x145/0x170 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
NMI backtrace for cpu 0
CPU: 0 PID: 10847 Comm: syz-executor.5 Not tainted 5.10.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0xa3/0xc8 lib/dump_stack.c:118
 nmi_cpu_backtrace.cold.8+0x53/0x6d lib/nmi_backtrace.c:105
 nmi_trigger_cpumask_backtrace+0xd5/0xf0 lib/nmi_backtrace.c:62
 trigger_single_cpu_backtrace include/linux/nmi.h:164 [inline]
 rcu_dump_cpu_stacks+0xa2/0xce kernel/rcu/tree_stall.h:318
 print_cpu_stall kernel/rcu/tree_stall.h:551 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:625 [inline]
 rcu_pending kernel/rcu/tree.c:3694 [inline]
 rcu_sched_clock_irq.cold.93+0x61/0x52b kernel/rcu/tree.c:2567
 update_process_times+0x50/0x80 kernel/time/timer.c:1709
 tick_sched_handle.isra.24+0x1a/0x50 kernel/time/tick-sched.c:176
 tick_sched_timer+0x6c/0x80 kernel/time/tick-sched.c:1328
 __run_hrtimer kernel/time/hrtimer.c:1519 [inline]
 __hrtimer_run_queues+0x1e3/0x4f0 kernel/time/hrtimer.c:1583
 hrtimer_interrupt+0xf9/0x210 kernel/time/hrtimer.c:1645
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline]
 __sysvec_apic_timer_interrupt+0x8e/0x290 arch/x86/kernel/apic/apic.c:1097
 asm_call_irq_on_stack+0xf/0x20
 </IRQ>
 __run_sysvec_on_irqstack arch/x86/include/asm/irq_stack.h:37 [inline]
 run_sysvec_on_irqstack_cond arch/x86/include/asm/irq_stack.h:89 [inline]
 sysvec_apic_timer_interrupt+0xcc/0xf0 arch/x86/kernel/apic/apic.c:1091
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:631
RIP: 0010:native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:61
Code: 5b c3 65 48 8b 04 25 c0 7e 01 00 f0 80 48 02 20 48 8b 00 a8 08 75 c3 e9 7c ff ff ff e9 07 00 00 00 0f 00 2d dc ab 55 00 fb f4 <c3> 90 e9 07 00 00 00 0f 00 2d cc ab 55 00 f4 c3 cc cc e8 bb 07 ff
RSP: 0018:ffffc90004f6bd98 EFLAGS: 00000286
RAX: 000000000000c0a4 RBX: 0000000000000282 RCX: 0000000000000002
RDX: 0000000000000000 RSI: ffffffff83f2aaa3 RDI: ffffffff83f679ae
RBP: 0000000000000003 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000001 R11: 0000000000000000 R12: ffff888100dfb8c8
R13: 0000000000000001 R14: 0000000000000100 R15: 0000000000040000
 arch_safe_halt arch/x86/include/asm/paravirt.h:150 [inline]
 kvm_wait+0xa1/0xc0 arch/x86/kernel/kvm.c:851
 pv_wait arch/x86/include/asm/paravirt.h:564 [inline]
 pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:470 [inline]
 __pv_queued_spin_lock_slowpath+0x295/0x2d0 kernel/locking/qspinlock.c:508
 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:554 [inline]
 queued_spin_lock_slowpath arch/x86/include/asm/qspinlock.h:51 [inline]
 queued_spin_lock include/asm-generic/qspinlock.h:85 [inline]
 do_raw_spin_lock+0xb6/0xc0 kernel/locking/spinlock_debug.c:113
 spin_lock_bh include/linux/spinlock.h:359 [inline]
 lock_sock_nested+0x2c/0x90 net/core/sock.c:3036
 lock_sock include/net/sock.h:1581 [inline]
 tipc_release+0x2c/0x870 net/tipc/socket.c:624
 __sock_release+0x32/0xa0 net/socket.c:596
 sock_close+0xf/0x20 net/socket.c:1277
 __fput+0xaa/0x250 fs/file_table.c:281
 task_work_run+0x68/0xb0 kernel/task_work.c:151
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:164 [inline]
 exit_to_user_mode_prepare+0x211/0x220 kernel/entry/common.c:191
 syscall_exit_to_user_mode+0x7a/0x2c0 kernel/entry/common.c:266
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x416721
Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 04 1b 00 00 c3 48 83 ec 08 e8 0a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007ffc9f489480 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 0000000000416721
RDX: 0000001b30420000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000
R10: 00007ffc9f489570 R11: 0000000000000293 R12: 000000000078c900
R13: 000000000078c900 R14: ffffffffffffffff R15: 000000000078bfac