bisecting fixing commit since ae4b064e2a616b545acf02b8f50cc513b32c7522
building syzkaller on 08003f6440deafc4e193b159c4acece64f7864b1
testing commit ae4b064e2a616b545acf02b8f50cc513b32c7522 with gcc (GCC) 8.1.0
kernel signature: 8670acd68e3ddd6a03bbac8893021c80fd56023d801488e62e165f64fc4e4810
run #0: crashed: INFO: rcu detected stall in corrupted
run #1: crashed: INFO: rcu detected stall in chrdev_open
run #2: crashed: INFO: rcu detected stall in corrupted
run #3: crashed: INFO: rcu detected stall in chrdev_open
run #4: crashed: INFO: rcu detected stall in chrdev_open
run #5: crashed: INFO: rcu detected stall in chrdev_open
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 corrupted
run #9: crashed: INFO: rcu detected stall in chrdev_open
testing current HEAD 15bc20c6af4ceee97a1f90b43c0e386643c071b4
testing commit 15bc20c6af4ceee97a1f90b43c0e386643c071b4 with gcc (GCC) 8.1.0
kernel signature: 3e82b159455bc885e9c86f39a47f904c986e8fa792a038dd461883547b688c69
run #0: crashed: INFO: rcu detected stall in chrdev_open
run #1: crashed: INFO: rcu detected stall in corrupted
run #2: crashed: INFO: rcu detected stall in corrupted
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 chrdev_open
run #8: crashed: INFO: rcu detected stall in corrupted
run #9: crashed: INFO: rcu detected stall in chrdev_open
revisions tested: 2, total time: 22m5.163239488s (build: 10m25.743057624s, test: 10m48.786620196s)
the crash still happens on HEAD
commit msg: Merge tag 'tty-5.9-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
crash: INFO: rcu detected stall in chrdev_open
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1):
------------[ cut here ]------------
WARNING: CPU: 0 PID: 9746 at kernel/sched/core.c:3013 try_invoke_on_locked_down_task+0x9c/0x120 kernel/sched/core.c:3033
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 9746 Comm: syz-executor.0 Not tainted 5.9.0-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+0xb9/0xf1 lib/dump_stack.c:118
 panic+0x115/0x2fa kernel/panic.c:231
 __warn.cold.13+0x20/0x28 kernel/panic.c:600
 report_bug+0xc5/0x100 lib/bug.c:198
 handle_bug+0x39/0xa0 arch/x86/kernel/traps.c:234
 exc_invalid_op+0x18/0x70 arch/x86/kernel/traps.c:254
 asm_exc_invalid_op+0x12/0x20 arch/x86/include/asm/idtentry.h:536
RIP: 0010:try_invoke_on_locked_down_task+0x9c/0x120 kernel/sched/core.c:3013
Code: e8 59 c9 e7 01 44 89 e8 48 8b 4d d0 65 48 33 0c 25 28 00 00 00 0f 85 81 00 00 00 48 83 c4 20 5b 41 5c 41 5d 41 5e 41 5f 5d c3 <0f> 0b eb 9e 48 8d 75 c0 48 89 df 45 31 ed e8 a1 c1 ff ff 8b 4b 40
RSP: 0018:ffffc90000003db8 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff888126bee080 RCX: 0000000000000001
RDX: ffffc90000003e4c RSI: ffffffff812686f0 RDI: ffff888126bee080
RBP: ffffc90000003e00 R08: 0000000000000000 R09: 0000000000000033
R10: ffff888126bee400 R11: 0000000000000000 R12: 000000000002e9c0
R13: ffffffff842e24c0 R14: ffffffff812686f0 R15: ffffc90000003e4c
 rcu_print_task_stall kernel/rcu/tree_stall.h:267 [inline]
 print_other_cpu_stall kernel/rcu/tree_stall.h:475 [inline]
 check_cpu_stall kernel/rcu/tree_stall.h:634 [inline]
 rcu_pending kernel/rcu/tree.c:3637 [inline]
 rcu_sched_clock_irq.cold.93+0x24b/0x545 kernel/rcu/tree.c:2519
 update_process_times+0x23/0x60 kernel/time/timer.c:1710
 tick_sched_handle.isra.23+0x20/0x60 kernel/time/tick-sched.c:176
 tick_sched_timer+0x74/0x90 kernel/time/tick-sched.c:1328
 __run_hrtimer kernel/time/hrtimer.c:1524 [inline]
 __hrtimer_run_queues+0x1f1/0x520 kernel/time/hrtimer.c:1588
 hrtimer_interrupt+0xfc/0x210 kernel/time/hrtimer.c:1650
 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1080 [inline]
 __sysvec_apic_timer_interrupt+0x93/0x2b0 arch/x86/kernel/apic/apic.c:1097
 asm_call_on_stack+0xf/0x20 arch/x86/entry/entry_64.S:706
 </IRQ>
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:22 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:48 [inline]
 sysvec_apic_timer_interrupt+0xca/0xf0 arch/x86/kernel/apic/apic.c:1091
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:581
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x33/0x60 kernel/locking/spinlock.c:199
Code: 83 c7 18 48 8b 75 08 e8 cb 48 1b fe 48 89 df e8 a3 a7 1b fe e8 ae ea 25 fe 48 83 3d ee 9c 22 01 00 74 1f fb 66 0f 1f 44 00 00 <bf> 01 00 00 00 e8 e3 d2 17 fe 65 8b 05 1c bd f8 7c 85 c0 74 05 5b
RSP: 0018:ffffc90002c47b98 EFLAGS: 00000286
RAX: 0000000001a98b2d RBX: ffff88812c02dbc0 RCX: 0000000000000001
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8308c142
RBP: ffffc90002c47ba0 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000023 R11: 0000000000000000 R12: ffff88810ceac1c0
R13: ffff88810ceac1c0 R14: ffff88812c02dbd8 R15: ffff88812c02dbc0
 rq_unlock_irq kernel/sched/sched.h:1317 [inline]
 __schedule+0x7f0/0x880 kernel/sched/core.c:4530
 schedule+0x3b/0xf0 kernel/sched/core.c:4602
 tty_open+0x19c/0x4b0 drivers/tty/tty_io.c:2038
 chrdev_open+0xa0/0x1d0 fs/char_dev.c:414
 do_dentry_open+0x163/0x3d0 fs/open.c:817
 vfs_open+0x28/0x30 fs/open.c:931
 do_open fs/namei.c:3251 [inline]
 path_openat+0x476/0xa90 fs/namei.c:3368
 do_filp_open+0x8e/0x100 fs/namei.c:3395
 do_sys_openat2+0x218/0x2d0 fs/open.c:1168
 do_sys_open+0x48/0x80 fs/open.c:1184
 __do_sys_openat fs/open.c:1200 [inline]
 __se_sys_openat fs/open.c:1195 [inline]
 __x64_sys_openat+0x1b/0x20 fs/open.c:1195
 do_syscall_64+0x31/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45a989
Code: 2d b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 fb b5 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f9c167dbc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 000000000045a989
RDX: 0000000000000000 RSI: 0000000020000380 RDI: ffffffffffffff9c
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f9c167dc6d4
R13: 00000000004c86f8 R14: 00000000004dfaa8 R15: 00000000ffffffff
Kernel Offset: disabled
Rebooting in 86400 seconds..