INFO: rcu detected stall in file_tty

Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
upstream	INFO: rcu detected stall in file_tty_write fbdev				1	1340d	1340d	0/28	auto-closed as invalid on 2021/07/28 18:00
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P14403/1:b..l
rcu: 	(detected by 1, t=10502 jiffies, g=82313, q=466 ncpus=2)
task:syz-executor.0  state:R  running task     stack:24344 pid:14403 tgid:14401 ppid:5106   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5408 [inline]
 __schedule+0x1796/0x49d0 kernel/sched/core.c:6745
 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:7067
 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_acquire+0x264/0x550 kernel/locking/lockdep.c:5758
Code: 2b 00 74 08 4c 89 f7 e8 ba 3a 86 00 f6 44 24 61 02 0f 85 85 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25
RSP: 0018:ffffc900045bf4c0 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 1ffff920008b7ea4 RCX: 0000000000000001
RDX: dffffc0000000000 RSI: ffffffff8bcacd00 RDI: ffffffff8c1f1ec0
RBP: ffffc900045bf618 R08: ffffffff92f74587 R09: 1ffffffff25ee8b0
R10: dffffc0000000000 R11: fffffbfff25ee8b1 R12: 1ffff920008b7ea0
R13: dffffc0000000000 R14: ffffc900045bf520 R15: 0000000000000246
 rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
 rcu_read_lock include/linux/rcupdate.h:781 [inline]
 atomic_notifier_call_chain+0x43/0x180 kernel/notifier.c:230
 do_con_write+0xab1/0x4c30 drivers/tty/vt/vt.c:3086
 con_write+0x26/0x40 drivers/tty/vt/vt.c:3434
 process_output_block drivers/tty/n_tty.c:574 [inline]
 n_tty_write+0xd6a/0x1230 drivers/tty/n_tty.c:2379
 iterate_tty_write drivers/tty/tty_io.c:1021 [inline]
 file_tty_write+0x54f/0x9b0 drivers/tty/tty_io.c:1096
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0xa72/0xc90 fs/read_write.c:590
 ksys_write+0x1a0/0x2c0 fs/read_write.c:643
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe0d7c7cf69
RSP: 002b:00007fe0d8a500c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fe0d7db3f80 RCX: 00007fe0d7c7cf69
RDX: 0000000000001006 RSI: 0000000020001040 RDI: 0000000000000004
RBP: 00007fe0d7cda6fe R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007fe0d7db3f80 R15: 00007ffc619ab598
 </TASK>
rcu: rcu_preempt kthread starved for 10204 jiffies! g82313 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->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:R  running task     stack:24912 pid:17    tgid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5408 [inline]
 __schedule+0x1796/0x49d0 kernel/sched/core.c:6745
 __schedule_loop kernel/sched/core.c:6822 [inline]
 schedule+0x14b/0x320 kernel/sched/core.c:6837
 schedule_timeout+0x1be/0x310 kernel/time/timer.c:2581
 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2000
 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2202
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 6.10.0-rc2-syzkaller-00366-g771ed66105de #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:37 [inline]
RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:72 [inline]
RIP: 0010:acpi_safe_halt+0x21/0x30 drivers/acpi/processor_idle.c:113
Code: 90 90 90 90 90 90 90 90 90 65 48 8b 04 25 c0 d4 03 00 48 f7 00 08 00 00 00 75 10 66 90 0f 00 2d e5 9f aa 00 f3 0f 1e fa fb f4 <fa> c3 cc cc cc cc 66 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90
RSP: 0018:ffffc900001a7d08 EFLAGS: 00000246
RAX: ffff8880176e0000 RBX: ffff88801928f864 RCX: 00000000017a6089
RDX: 0000000000000001 RSI: ffff88801928f800 RDI: ffff88801928f864
RBP: 000000000003a578 R08: ffff8880b9537d0b R09: 1ffff110172a6fa1
R10: dffffc0000000000 R11: ffffffff8b7e0a30 R12: ffff88801c384800
R13: 0000000000000000 R14: 0000000000000001 R15: ffffffff8eabbd00
FS:  0000000000000000(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b32d30000 CR3: 00000000666ac000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 </IRQ>
 <TASK>
 acpi_idle_enter+0xe4/0x140 drivers/acpi/processor_idle.c:707
 cpuidle_enter_state+0x112/0x480 drivers/cpuidle/cpuidle.c:267
 cpuidle_enter+0x5d/0xa0 drivers/cpuidle/cpuidle.c:388
 call_cpuidle kernel/sched/idle.c:155 [inline]
 cpuidle_idle_call kernel/sched/idle.c:236 [inline]
 do_idle+0x375/0x5d0 kernel/sched/idle.c:332
 cpu_startup_entry+0x42/0x60 kernel/sched/idle.c:430
 start_secondary+0x100/0x100 arch/x86/kernel/smpboot.c:313
 common_startup_64+0x13e/0x147
 </TASK>