------------[ cut here ]------------
======================================================
WARNING: possible circular locking dependency detected
6.11.0-rc6-syzkaller-gc763c4339688 #0 Not tainted
------------------------------------------------------
swapper/1/0 is trying to acquire lock:
ffffffff8dda8018 ((console_sem).lock){-...}-{2:2}, at: down_trylock+0x12/0x70 kernel/locking/semaphore.c:139

but task is already holding lock:
ffff88806a63edd8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:568 [inline]
ffff88806a63edd8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x7e/0x130 kernel/sched/core.c:553

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #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:560
       raw_spin_rq_lock kernel/sched/sched.h:1415 [inline]
       rq_lock kernel/sched/sched.h:1714 [inline]
       task_fork_fair+0x73/0x250 kernel/sched/fair.c:12710
       sched_cgroup_fork+0x3cf/0x510 kernel/sched/core.c:4633
       copy_process+0x43a1/0x8de0 kernel/fork.c:2483
       kernel_clone+0xfd/0x960 kernel/fork.c:2781
       user_mode_thread+0xb4/0xf0 kernel/fork.c:2859
       rest_init+0x23/0x2b0 init/main.c:712
       start_kernel+0x3df/0x4c0 init/main.c:1103
       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/0x13e0 kernel/sched/core.c:4051
       up+0x79/0xb0 kernel/locking/semaphore.c:191
       __up_console_sem kernel/printk/printk.c:340 [inline]
       __console_unlock kernel/printk/printk.c:2801 [inline]
       console_unlock+0x23e/0x290 kernel/printk/printk.c:3120
       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+0x408/0x4e0 drivers/gpu/drm/virtio/virtgpu_drv.c:92
       virtio_dev_probe+0x586/0x8a0 drivers/virtio/virtio.c:308
       call_driver_probe drivers/base/dd.c:578 [inline]
       really_probe+0x23e/0xa90 drivers/base/dd.c:657
       __driver_probe_device+0x1de/0x440 drivers/base/dd.c:799
       driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:829
       __driver_attach+0x283/0x580 drivers/base/dd.c:1215
       bus_for_each_dev+0x13c/0x1d0 drivers/base/bus.c:368
       bus_add_driver+0x2e9/0x690 drivers/base/bus.c:673
       driver_register+0x15c/0x4b0 drivers/base/driver.c:246
       do_one_initcall+0x128/0x700 init/main.c:1267
       do_initcall_level init/main.c:1329 [inline]
       do_initcalls init/main.c:1345 [inline]
       do_basic_setup init/main.c:1364 [inline]
       kernel_init_freeable+0x69d/0xca0 init/main.c:1578
       kernel_init+0x1c/0x2b0 init/main.c:1467
       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:3133 [inline]
       check_prevs_add kernel/locking/lockdep.c:3252 [inline]
       validate_chain kernel/locking/lockdep.c:3868 [inline]
       __lock_acquire+0x24ed/0x3cb0 kernel/locking/lockdep.c:5142
       lock_acquire kernel/locking/lockdep.c:5759 [inline]
       lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5724
       __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:323
       console_trylock kernel/printk/printk.c:2754 [inline]
       console_trylock_spinning kernel/printk/printk.c:1958 [inline]
       vprintk_emit+0x3d3/0x600 kernel/printk/printk.c:2347
       vprintk+0x7f/0xa0 kernel/printk/printk_safe.c:45
       _printk+0xc8/0x100 kernel/printk/printk.c:2373
       __report_bug lib/bug.c:195 [inline]
       report_bug+0x433/0x580 lib/bug.c:219
       handle_bug+0x3d/0x70 arch/x86/kernel/traps.c:239
       exc_invalid_op+0x17/0x50 arch/x86/kernel/traps.c:260
       asm_exc_invalid_op+0x1a/0x20 arch/x86/include/asm/idtentry.h:621
       lockdep_assert_rq_held kernel/sched/sched.h:1406 [inline]
       lockdep_assert_rq_held kernel/sched/sched.h:1404 [inline]
       rq_clock_task kernel/sched/sched.h:1562 [inline]
       update_stats_curr_start kernel/sched/fair.c:1301 [inline]
       set_next_entity+0x30d/0x670 kernel/sched/fair.c:5443
       set_next_task_fair+0x88/0x330 kernel/sched/fair.c:12875
       set_next_task kernel/sched/sched.h:2353 [inline]
       pick_next_task kernel/sched/core.c:5934 [inline]
       __schedule+0x114c/0x5490 kernel/sched/core.c:6484
       schedule_idle+0x59/0x90 kernel/sched/core.c:6647
       do_idle+0x287/0x3f0 kernel/sched/idle.c:354
       cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:424
       start_secondary+0x220/0x2b0 arch/x86/kernel/smpboot.c:313
       common_startup_64+0x13e/0x148

other info that might help us debug this:

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

 Possible unsafe locking scenario:

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

 *** DEADLOCK ***

1 lock held by swapper/1/0:
 #0: ffff88806a63edd8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:568 [inline]
 #0: ffff88806a63edd8 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x7e/0x130 kernel/sched/core.c:553

stack backtrace:
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.11.0-rc6-syzkaller-gc763c4339688 #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:93 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:119
 check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2186
 check_prev_add kernel/locking/lockdep.c:3133 [inline]
 check_prevs_add kernel/locking/lockdep.c:3252 [inline]
 validate_chain kernel/locking/lockdep.c:3868 [inline]
 __lock_acquire+0x24ed/0x3cb0 kernel/locking/lockdep.c:5142
 lock_acquire kernel/locking/lockdep.c:5759 [inline]
 lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5724
 __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:323
 console_trylock kernel/printk/printk.c:2754 [inline]
 console_trylock_spinning kernel/printk/printk.c:1958 [inline]
 vprintk_emit+0x3d3/0x600 kernel/printk/printk.c:2347
 vprintk+0x7f/0xa0 kernel/printk/printk_safe.c:45
 _printk+0xc8/0x100 kernel/printk/printk.c:2373
 __report_bug lib/bug.c:195 [inline]
 report_bug+0x433/0x580 lib/bug.c:219
 handle_bug+0x3d/0x70 arch/x86/kernel/traps.c:239
 exc_invalid_op+0x17/0x50 arch/x86/kernel/traps.c:260
 asm_exc_invalid_op+0x1a/0x20 arch/x86/include/asm/idtentry.h:621
RIP: 0010:lockdep_assert_rq_held kernel/sched/sched.h:1406 [inline]
RIP: 0010:lockdep_assert_rq_held kernel/sched/sched.h:1404 [inline]
RIP: 0010:rq_clock_task kernel/sched/sched.h:1562 [inline]
RIP: 0010:update_stats_curr_start kernel/sched/fair.c:1301 [inline]
RIP: 0010:set_next_entity+0x30d/0x670 kernel/sched/fair.c:5443
Code: 00 fc ff df 4c 89 e1 48 c1 e9 03 80 3c 11 00 0f 85 da 02 00 00 48 2b 45 60 4c 39 f0 49 0f 42 c6 49 89 45 68 e9 88 fe ff ff 90 <0f> 0b 90 e9 06 fe ff ff 0f 1f 44 00 00 48 89 ee 4c 89 ef e8 cb 41
RSP: 0018:ffffc90000187be0 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff88806a93edc0 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff8b4cda40 RDI: ffffffff8bb0f9c0
RBP: ffff8880395624c0 R08: 0000000000000000 R09: fffffbfff2028873
R10: ffffffff9014439f R11: 0000000000000000 R12: ffff888030c98178
R13: ffff888030c98000 R14: ffff888039562440 R15: ffff88806a73edc0
 set_next_task_fair+0x88/0x330 kernel/sched/fair.c:12875
 set_next_task kernel/sched/sched.h:2353 [inline]
 pick_next_task kernel/sched/core.c:5934 [inline]
 __schedule+0x114c/0x5490 kernel/sched/core.c:6484
 schedule_idle+0x59/0x90 kernel/sched/core.c:6647
 do_idle+0x287/0x3f0 kernel/sched/idle.c:354
 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:424
 start_secondary+0x220/0x2b0 arch/x86/kernel/smpboot.c:313
 common_startup_64+0x13e/0x148
 </TASK>
WARNING: CPU: 1 PID: 0 at kernel/sched/sched.h:1406 lockdep_assert_rq_held kernel/sched/sched.h:1406 [inline]
WARNING: CPU: 1 PID: 0 at kernel/sched/sched.h:1406 lockdep_assert_rq_held kernel/sched/sched.h:1404 [inline]
WARNING: CPU: 1 PID: 0 at kernel/sched/sched.h:1406 rq_clock_task kernel/sched/sched.h:1562 [inline]
WARNING: CPU: 1 PID: 0 at kernel/sched/sched.h:1406 update_stats_curr_start kernel/sched/fair.c:1301 [inline]
WARNING: CPU: 1 PID: 0 at kernel/sched/sched.h:1406 set_next_entity+0x30d/0x670 kernel/sched/fair.c:5443
Modules linked in:
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted 6.11.0-rc6-syzkaller-gc763c4339688 #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:lockdep_assert_rq_held kernel/sched/sched.h:1406 [inline]
RIP: 0010:lockdep_assert_rq_held kernel/sched/sched.h:1404 [inline]
RIP: 0010:rq_clock_task kernel/sched/sched.h:1562 [inline]
RIP: 0010:update_stats_curr_start kernel/sched/fair.c:1301 [inline]
RIP: 0010:set_next_entity+0x30d/0x670 kernel/sched/fair.c:5443
Code: 00 fc ff df 4c 89 e1 48 c1 e9 03 80 3c 11 00 0f 85 da 02 00 00 48 2b 45 60 4c 39 f0 49 0f 42 c6 49 89 45 68 e9 88 fe ff ff 90 <0f> 0b 90 e9 06 fe ff ff 0f 1f 44 00 00 48 89 ee 4c 89 ef e8 cb 41
RSP: 0018:ffffc90000187be0 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff88806a93edc0 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff8b4cda40 RDI: ffffffff8bb0f9c0
RBP: ffff8880395624c0 R08: 0000000000000000 R09: fffffbfff2028873
R10: ffffffff9014439f R11: 0000000000000000 R12: ffff888030c98178
R13: ffff888030c98000 R14: ffff888039562440 R15: ffff88806a73edc0
FS:  0000000000000000(0000) GS:ffff88806a700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007eff388c66e4 CR3: 0000000031dce000 CR4: 0000000000350ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 set_next_task_fair+0x88/0x330 kernel/sched/fair.c:12875
 set_next_task kernel/sched/sched.h:2353 [inline]
 pick_next_task kernel/sched/core.c:5934 [inline]
 __schedule+0x114c/0x5490 kernel/sched/core.c:6484
 schedule_idle+0x59/0x90 kernel/sched/core.c:6647
 do_idle+0x287/0x3f0 kernel/sched/idle.c:354
 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:424
 start_secondary+0x220/0x2b0 arch/x86/kernel/smpboot.c:313
 common_startup_64+0x13e/0x148
 </TASK>