FAULT_INJECTION: forcing a failure.
name fail_usercopy, interval 1, probability 0, space 0, times 0
======================================================
WARNING: possible circular locking dependency detected
6.12.0-rc1-syzkaller-ge32cde8d2bd7 #0 Not tainted
------------------------------------------------------
syz.1.397/6905 is trying to acquire lock:
ffffffff8e1a5eb8 ((console_sem).lock){-...}-{2:2}, at: down_trylock+0x12/0x70 kernel/locking/semaphore.c:139

but task is already holding lock:
ffff88806a62a858 (&base->lock){-.-.}-{2:2}, at: __mod_timer+0x6c1/0xdc0 kernel/time/timer.c:1164

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #3 (&base->lock){-.-.}-{2:2}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
       lock_timer_base+0x5d/0x220 kernel/time/timer.c:1051
       __mod_timer+0x426/0xdc0 kernel/time/timer.c:1132
       add_timer_global+0x8a/0xc0 kernel/time/timer.c:1330
       __queue_delayed_work+0x1ba/0x2e0 kernel/workqueue.c:2523
       queue_delayed_work_on+0x12a/0x150 kernel/workqueue.c:2552
       psi_task_change+0x1b4/0x2e0 kernel/sched/psi.c:913
       psi_enqueue kernel/sched/stats.h:143 [inline]
       enqueue_task+0x1a5/0x350 kernel/sched/core.c:2017
       activate_task kernel/sched/core.c:2062 [inline]
       wake_up_new_task+0x662/0xd30 kernel/sched/core.c:4816
       kernel_clone+0x236/0x960 kernel/fork.c:2818
       user_mode_thread+0xb4/0xf0 kernel/fork.c:2865
       rest_init+0x23/0x2b0 init/main.c:712
       start_kernel+0x3e4/0x4d0 init/main.c:1105
       x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:507
       x86_64_start_kernel+0xb2/0xc0 arch/x86/kernel/head64.c:488
       common_startup_64+0x13e/0x148

-> #2 (&rq->__lock){-.-.}-{2:2}:
       _raw_spin_lock_nested+0x31/0x40 kernel/locking/spinlock.c:378
       raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:593
       raw_spin_rq_lock kernel/sched/sched.h:1505 [inline]
       task_rq_lock+0xcf/0x3b0 kernel/sched/core.c:695
       cgroup_move_task+0x82/0x250 kernel/sched/psi.c:1161
       css_set_move_task+0x288/0x5f0 kernel/cgroup/cgroup.c:898
       cgroup_post_fork+0x1c6/0x910 kernel/cgroup/cgroup.c:6692
       copy_process+0x50e4/0x8dc0 kernel/fork.c:2601
       kernel_clone+0xfd/0x960 kernel/fork.c:2787
       user_mode_thread+0xb4/0xf0 kernel/fork.c:2865
       rest_init+0x23/0x2b0 init/main.c:712
       start_kernel+0x3e4/0x4d0 init/main.c:1105
       x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:507
       x86_64_start_kernel+0xb2/0xc0 arch/x86/kernel/head64.c:488
       common_startup_64+0x13e/0x148

-> #1 (&p->pi_lock){-.-.}-{2:2}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
       class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:551 [inline]
       try_to_wake_up+0x9a/0x1440 kernel/sched/core.c:4154
       up+0x79/0xb0 kernel/locking/semaphore.c:191
       __up_console_sem+0x85/0xe0 kernel/printk/printk.c:343
       __console_unlock kernel/printk/printk.c:2844 [inline]
       __console_flush_and_unlock kernel/printk/printk.c:3241 [inline]
       console_unlock+0x1dc/0x210 kernel/printk/printk.c:3279
       vga_remove_vgacon drivers/pci/vgaarb.c:186 [inline]
       vga_remove_vgacon+0x90/0xd0 drivers/pci/vgaarb.c:167
       __aperture_remove_legacy_vga_devices drivers/video/aperture.c:331 [inline]
       aperture_remove_conflicting_pci_devices+0x16a/0x1e0 drivers/video/aperture.c:369
       virtio_gpu_pci_quirk drivers/gpu/drm/virtio/virtgpu_drv.c:61 [inline]
       virtio_gpu_probe+0x40c/0x4f0 drivers/gpu/drm/virtio/virtgpu_drv.c:92
       virtio_dev_probe+0x586/0x8a0 drivers/virtio/virtio.c:341
       call_driver_probe drivers/base/dd.c:579 [inline]
       really_probe+0x23e/0xa90 drivers/base/dd.c:658
       __driver_probe_device+0x1de/0x440 drivers/base/dd.c:800
       driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:830
       __driver_attach+0x283/0x580 drivers/base/dd.c:1216
       bus_for_each_dev+0x13c/0x1d0 drivers/base/bus.c:370
       bus_add_driver+0x2e9/0x690 drivers/base/bus.c:675
       driver_register+0x15c/0x4b0 drivers/base/driver.c:246
       do_one_initcall+0x128/0x700 init/main.c:1269
       do_initcall_level init/main.c:1331 [inline]
       do_initcalls init/main.c:1347 [inline]
       do_basic_setup init/main.c:1366 [inline]
       kernel_init_freeable+0x5c7/0x900 init/main.c:1580
       kernel_init+0x1c/0x2b0 init/main.c:1469
       ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #0 ((console_sem).lock){-...}-{2:2}:
       check_prev_add kernel/locking/lockdep.c:3161 [inline]
       check_prevs_add kernel/locking/lockdep.c:3280 [inline]
       validate_chain kernel/locking/lockdep.c:3904 [inline]
       __lock_acquire+0x250b/0x3ce0 kernel/locking/lockdep.c:5202
       lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5825
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
       down_trylock+0x12/0x70 kernel/locking/semaphore.c:139
       __down_trylock_console_sem+0x40/0x140 kernel/printk/printk.c:326
       console_trylock kernel/printk/printk.c:2827 [inline]
       console_trylock_spinning kernel/printk/printk.c:1990 [inline]
       vprintk_emit+0x3ec/0x6f0 kernel/printk/printk.c:2406
       vprintk+0x7f/0xa0 kernel/printk/printk_safe.c:68
       _printk+0xc8/0x100 kernel/printk/printk.c:2432
       fail_dump lib/fault-inject.c:46 [inline]
       should_fail_ex+0x46c/0x5b0 lib/fault-inject.c:154
       strncpy_from_user+0x3b/0x2a0 lib/strncpy_from_user.c:118
       strncpy_from_user_nofault+0x7f/0x180 mm/maccess.c:186
       bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:215 [inline]
       ____bpf_probe_read_compat_str kernel/trace/bpf_trace.c:310 [inline]
       bpf_probe_read_compat_str+0xf1/0x170 kernel/trace/bpf_trace.c:306
       bpf_prog_d0e9ac47b081aec3+0x49/0x4b
       bpf_dispatcher_nop_func include/linux/bpf.h:1257 [inline]
       __bpf_prog_run include/linux/filter.h:701 [inline]
       bpf_prog_run include/linux/filter.h:708 [inline]
       __bpf_trace_run kernel/trace/bpf_trace.c:2318 [inline]
       bpf_trace_run2+0x231/0x590 kernel/trace/bpf_trace.c:2359
       __bpf_trace_timer_start+0xc7/0x100 include/trace/events/timer.h:52
       __traceiter_timer_start+0x64/0xb0 include/trace/events/timer.h:52
       trace_timer_start include/trace/events/timer.h:52 [inline]
       enqueue_timer+0x2b4/0x550 kernel/time/timer.c:663
       internal_add_timer kernel/time/timer.c:688 [inline]
       __mod_timer+0x8d7/0xdc0 kernel/time/timer.c:1183
       add_timer_global+0x8a/0xc0 kernel/time/timer.c:1330
       __queue_delayed_work+0x1ba/0x2e0 kernel/workqueue.c:2523
       queue_delayed_work_on+0x12a/0x150 kernel/workqueue.c:2552
       queue_delayed_work include/linux/workqueue.h:677 [inline]
       fbcon_add_cursor_work drivers/video/fbdev/core/fbcon.c:406 [inline]
       fbcon_cursor+0x4aa/0x5f0 drivers/video/fbdev/core/fbcon.c:1336
       set_cursor drivers/tty/vt/vt.c:859 [inline]
       set_cursor+0x1d8/0x250 drivers/tty/vt/vt.c:850
       con_flush_chars+0x66/0x80 drivers/tty/vt/vt.c:3504
       n_tty_write+0xe17/0x1140 drivers/tty/n_tty.c:2405
       iterate_tty_write drivers/tty/tty_io.c:1015 [inline]
       file_tty_write.constprop.0+0x506/0x9a0 drivers/tty/tty_io.c:1090
       new_sync_write fs/read_write.c:590 [inline]
       vfs_write+0x6b5/0x1140 fs/read_write.c:683
       ksys_write+0x12f/0x260 fs/read_write.c:736
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
  (console_sem).lock --> &rq->__lock --> &base->lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&base->lock);
                               lock(&rq->__lock);
                               lock(&base->lock);
  lock((console_sem).lock);

 *** DEADLOCK ***

6 locks held by syz.1.397/6905:
 #0: ffff88802f66f0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
 #1: ffff88802f66f130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: tty_write_lock drivers/tty/tty_io.c:948 [inline]
 #1: ffff88802f66f130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: iterate_tty_write drivers/tty/tty_io.c:967 [inline]
 #1: ffff88802f66f130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: file_tty_write.constprop.0+0x281/0x9a0 drivers/tty/tty_io.c:1090
 #2: ffff88802f66f2e8 (&tty->termios_rwsem){++++}-{3:3}, at: n_tty_write+0x1bd/0x1140 drivers/tty/n_tty.c:2372
 #3: ffffffff8e1a5a40 (console_lock){+.+.}-{0:0}, at: con_flush_chars+0x5e/0x80 drivers/tty/vt/vt.c:3503
 #4: ffff88806a62a858 (&base->lock){-.-.}-{2:2}, at: __mod_timer+0x6c1/0xdc0 kernel/time/timer.c:1164
 #5: ffffffff8e1b8340 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #5: ffffffff8e1b8340 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #5: ffffffff8e1b8340 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2317 [inline]
 #5: ffffffff8e1b8340 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run2+0x1c2/0x590 kernel/trace/bpf_trace.c:2359

stack backtrace:
CPU: 0 UID: 0 PID: 6905 Comm: syz.1.397 Not tainted 6.12.0-rc1-syzkaller-ge32cde8d2bd7 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_circular_bug+0x41c/0x610 kernel/locking/lockdep.c:2074
 check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2206
 check_prev_add kernel/locking/lockdep.c:3161 [inline]
 check_prevs_add kernel/locking/lockdep.c:3280 [inline]
 validate_chain kernel/locking/lockdep.c:3904 [inline]
 __lock_acquire+0x250b/0x3ce0 kernel/locking/lockdep.c:5202
 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5825
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
 down_trylock+0x12/0x70 kernel/locking/semaphore.c:139
 __down_trylock_console_sem+0x40/0x140 kernel/printk/printk.c:326
 console_trylock kernel/printk/printk.c:2827 [inline]
 console_trylock_spinning kernel/printk/printk.c:1990 [inline]
 vprintk_emit+0x3ec/0x6f0 kernel/printk/printk.c:2406
 vprintk+0x7f/0xa0 kernel/printk/printk_safe.c:68
 _printk+0xc8/0x100 kernel/printk/printk.c:2432
 fail_dump lib/fault-inject.c:46 [inline]
 should_fail_ex+0x46c/0x5b0 lib/fault-inject.c:154
 strncpy_from_user+0x3b/0x2a0 lib/strncpy_from_user.c:118
 strncpy_from_user_nofault+0x7f/0x180 mm/maccess.c:186
 bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:215 [inline]
 ____bpf_probe_read_compat_str kernel/trace/bpf_trace.c:310 [inline]
 bpf_probe_read_compat_str+0xf1/0x170 kernel/trace/bpf_trace.c:306
 bpf_prog_d0e9ac47b081aec3+0x49/0x4b
 bpf_dispatcher_nop_func include/linux/bpf.h:1257 [inline]
 __bpf_prog_run include/linux/filter.h:701 [inline]
 bpf_prog_run include/linux/filter.h:708 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2318 [inline]
 bpf_trace_run2+0x231/0x590 kernel/trace/bpf_trace.c:2359
 __bpf_trace_timer_start+0xc7/0x100 include/trace/events/timer.h:52
 __traceiter_timer_start+0x64/0xb0 include/trace/events/timer.h:52
 trace_timer_start include/trace/events/timer.h:52 [inline]
 enqueue_timer+0x2b4/0x550 kernel/time/timer.c:663
 internal_add_timer kernel/time/timer.c:688 [inline]
 __mod_timer+0x8d7/0xdc0 kernel/time/timer.c:1183
 add_timer_global+0x8a/0xc0 kernel/time/timer.c:1330
 __queue_delayed_work+0x1ba/0x2e0 kernel/workqueue.c:2523
 queue_delayed_work_on+0x12a/0x150 kernel/workqueue.c:2552
 queue_delayed_work include/linux/workqueue.h:677 [inline]
 fbcon_add_cursor_work drivers/video/fbdev/core/fbcon.c:406 [inline]
 fbcon_cursor+0x4aa/0x5f0 drivers/video/fbdev/core/fbcon.c:1336
 set_cursor drivers/tty/vt/vt.c:859 [inline]
 set_cursor+0x1d8/0x250 drivers/tty/vt/vt.c:850
 con_flush_chars+0x66/0x80 drivers/tty/vt/vt.c:3504
 n_tty_write+0xe17/0x1140 drivers/tty/n_tty.c:2405
 iterate_tty_write drivers/tty/tty_io.c:1015 [inline]
 file_tty_write.constprop.0+0x506/0x9a0 drivers/tty/tty_io.c:1090
 new_sync_write fs/read_write.c:590 [inline]
 vfs_write+0x6b5/0x1140 fs/read_write.c:683
 ksys_write+0x12f/0x260 fs/read_write.c:736
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5121d7def9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f5122afb038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f5121f35f80 RCX: 00007f5121d7def9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006
RBP: 00007f5122afb090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 0000000000000000 R14: 00007f5121f35f80 R15: 00007ffee80aa2c8
 </TASK>
CPU: 0 UID: 0 PID: 6905 Comm: syz.1.397 Not tainted 6.12.0-rc1-syzkaller-ge32cde8d2bd7 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 fail_dump lib/fault-inject.c:53 [inline]
 should_fail_ex+0x497/0x5b0 lib/fault-inject.c:154
 strncpy_from_user+0x3b/0x2a0 lib/strncpy_from_user.c:118
 strncpy_from_user_nofault+0x7f/0x180 mm/maccess.c:186
 bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:215 [inline]
 ____bpf_probe_read_compat_str kernel/trace/bpf_trace.c:310 [inline]
 bpf_probe_read_compat_str+0xf1/0x170 kernel/trace/bpf_trace.c:306
 bpf_prog_d0e9ac47b081aec3+0x49/0x4b
 bpf_dispatcher_nop_func include/linux/bpf.h:1257 [inline]
 __bpf_prog_run include/linux/filter.h:701 [inline]
 bpf_prog_run include/linux/filter.h:708 [inline]
 __bpf_trace_run kernel/trace/bpf_trace.c:2318 [inline]
 bpf_trace_run2+0x231/0x590 kernel/trace/bpf_trace.c:2359
 __bpf_trace_timer_start+0xc7/0x100 include/trace/events/timer.h:52
 __traceiter_timer_start+0x64/0xb0 include/trace/events/timer.h:52
 trace_timer_start include/trace/events/timer.h:52 [inline]
 enqueue_timer+0x2b4/0x550 kernel/time/timer.c:663
 internal_add_timer kernel/time/timer.c:688 [inline]
 __mod_timer+0x8d7/0xdc0 kernel/time/timer.c:1183
 add_timer_global+0x8a/0xc0 kernel/time/timer.c:1330
 __queue_delayed_work+0x1ba/0x2e0 kernel/workqueue.c:2523
 queue_delayed_work_on+0x12a/0x150 kernel/workqueue.c:2552
 queue_delayed_work include/linux/workqueue.h:677 [inline]
 fbcon_add_cursor_work drivers/video/fbdev/core/fbcon.c:406 [inline]
 fbcon_cursor+0x4aa/0x5f0 drivers/video/fbdev/core/fbcon.c:1336
 set_cursor drivers/tty/vt/vt.c:859 [inline]
 set_cursor+0x1d8/0x250 drivers/tty/vt/vt.c:850
 con_flush_chars+0x66/0x80 drivers/tty/vt/vt.c:3504
 n_tty_write+0xe17/0x1140 drivers/tty/n_tty.c:2405
 iterate_tty_write drivers/tty/tty_io.c:1015 [inline]
 file_tty_write.constprop.0+0x506/0x9a0 drivers/tty/tty_io.c:1090
 new_sync_write fs/read_write.c:590 [inline]
 vfs_write+0x6b5/0x1140 fs/read_write.c:683
 ksys_write+0x12f/0x260 fs/read_write.c:736
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5121d7def9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f5122afb038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f5121f35f80 RCX: 00007f5121d7def9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006
RBP: 00007f5122afb090 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 0000000000000000 R14: 00007f5121f35f80 R15: 00007ffee80aa2c8
 </TASK>