syzbot

INFO: task syz-executor.1:14506 blocked for more than 143 seconds.
      Not tainted 6.0.0-rc7-syzkaller-00130-g511cce163b75 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.1  state:D stack:27728 pid:14506 ppid: 14257 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5182 [inline]
 __schedule+0xadf/0x52b0 kernel/sched/core.c:6494
 schedule+0xda/0x1b0 kernel/sched/core.c:6570
 schedule_timeout+0x1db/0x2a0 kernel/time/timer.c:1911
 ___down_common kernel/locking/semaphore.c:225 [inline]
 __down_common+0x341/0x780 kernel/locking/semaphore.c:246
 down+0x70/0x90 kernel/locking/semaphore.c:63
 console_lock+0x28/0x80 kernel/printk/printk.c:2568
 do_fb_ioctl+0x2e4/0x6e0 drivers/video/fbdev/core/fbmem.c:1118
 fb_ioctl+0xe7/0x150 drivers/video/fbdev/core/fbmem.c:1201
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl fs/ioctl.c:856 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f89e8c8a5a9
RSP: 002b:00007f89e9e41168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f89e8dac050 RCX: 00007f89e8c8a5a9
RDX: 0000000020000000 RSI: 0000000000004601 RDI: 0000000000000006
RBP: 00007f89e8ce5580 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f89e92dfb1f R14: 00007f89e9e41300 R15: 0000000000022000
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/13:
 #0: ffffffff8bf888b0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x26/0xc70 kernel/rcu/tasks.h:507
1 lock held by rcu_tasks_trace/14:
 #0: ffffffff8bf885b0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x26/0xc70 kernel/rcu/tasks.h:507
1 lock held by khungtaskd/29:
 #0: ffffffff8bf89400 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6492
2 locks held by getty/3285:
 #0: ffff88814a4ed098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:244
 #1: ffffc90002d232f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xef0/0x13e0 drivers/tty/n_tty.c:2177
1 lock held by syz-executor.5/14176:
2 locks held by syz-executor.5/14614:
 #0: ffffffff8ca0c748 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2050 [inline]
 #0: ffffffff8ca0c748 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x593/0xff0 drivers/tty/tty_io.c:2133
 #1: ffff88807c1691c0 (&tty->legacy_mutex){+.+.}-{3:3}, at: tty_lock+0xbd/0x120 drivers/tty/tty_mutex.c:20

=============================================

NMI backtrace for cpu 1
CPU: 1 PID: 29 Comm: khungtaskd Not tainted 6.0.0-rc7-syzkaller-00130-g511cce163b75 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 nmi_cpu_backtrace.cold+0x46/0x14f lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x206/0x250 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
 watchdog+0xc18/0xf50 kernel/hung_task.c:369
 kthread+0x2e4/0x3a0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
NMI backtrace for cpu 0 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 0 skipped: idling at acpi_safe_halt drivers/acpi/processor_idle.c:112 [inline]
NMI backtrace for cpu 0 skipped: idling at acpi_idle_do_entry+0x1fd/0x2a0 drivers/acpi/processor_idle.c:572