------------[ cut here ]------------ ====================================================== WARNING: possible circular locking dependency detected 6.9.0-syzkaller-10713-g2a8120d7b482 #0 Not tainted ------------------------------------------------------ swapper/0/0 is trying to acquire lock: ffffffff8dba2e98 ((console_sem).lock){-.-.}-{2:2}, at: down_trylock+0x12/0x70 kernel/locking/semaphore.c:139 but task is already holding lock: ffff88802c02a858 (&base->lock){-.-.}-{2:2}, at: __run_timer_base kernel/time/timer.c:2427 [inline] ffff88802c02a858 (&base->lock){-.-.}-{2:2}, at: __run_timer_base kernel/time/timer.c:2421 [inline] ffff88802c02a858 (&base->lock){-.-.}-{2:2}, at: run_timer_base+0x109/0x190 kernel/time/timer.c:2437 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:2543 queue_delayed_work_on+0x12a/0x150 kernel/workqueue.c:2572 psi_task_change+0x1b4/0x2e0 kernel/sched/psi.c:912 psi_enqueue kernel/sched/stats.h:139 [inline] enqueue_task kernel/sched/core.c:2112 [inline] activate_task+0x213/0x400 kernel/sched/core.c:2146 wake_up_new_task+0x574/0xc90 kernel/sched/core.c:4900 kernel_clone+0x236/0x980 kernel/fork.c:2828 user_mode_thread+0xb4/0xf0 kernel/fork.c:2875 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 -> #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:559 raw_spin_rq_lock kernel/sched/sched.h:1406 [inline] rq_lock kernel/sched/sched.h:1702 [inline] task_fork_fair+0x73/0x250 kernel/sched/fair.c:12710 sched_cgroup_fork+0x3cf/0x510 kernel/sched/core.c:4844 copy_process+0x4710/0x6f50 kernel/fork.c:2499 kernel_clone+0xfd/0x980 kernel/fork.c:2797 user_mode_thread+0xb4/0xf0 kernel/fork.c:2875 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:553 [inline] try_to_wake_up+0x9a/0x13e0 kernel/sched/core.c:4262 up+0x79/0xb0 kernel/locking/semaphore.c:191 __up_console_sem kernel/printk/printk.c:340 [inline] __console_unlock kernel/printk/printk.c:2731 [inline] console_unlock+0x23e/0x290 kernel/printk/printk.c:3050 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+0x17f/0x210 drivers/video/aperture.c:374 bochs_pci_probe+0x101/0x1150 drivers/gpu/drm/tiny/bochs.c:651 local_pci_probe+0xde/0x1b0 drivers/pci/pci-driver.c:324 pci_call_probe drivers/pci/pci-driver.c:392 [inline] __pci_device_probe drivers/pci/pci-driver.c:417 [inline] pci_device_probe+0x294/0x7a0 drivers/pci/pci-driver.c:451 call_driver_probe drivers/base/dd.c:578 [inline] really_probe+0x23e/0xa90 drivers/base/dd.c:656 __driver_probe_device+0x1de/0x440 drivers/base/dd.c:798 driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:828 __driver_attach+0x283/0x580 drivers/base/dd.c:1214 bus_for_each_dev+0x13c/0x1d0 drivers/base/bus.c:368 bus_add_driver+0x2ed/0x640 drivers/base/bus.c:673 driver_register+0x15c/0x4b0 drivers/base/driver.c:246 drm_pci_register_driver_if_modeset include/drm/drm_module.h:69 [inline] bochs_pci_driver_init+0x67/0x80 drivers/gpu/drm/tiny/bochs.c:735 do_one_initcall+0x128/0x630 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+0x660/0xc50 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:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137 lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719 __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:2684 [inline] console_trylock_spinning kernel/printk/printk.c:1958 [inline] vprintk_emit kernel/printk/printk.c:2347 [inline] vprintk_emit+0xe4/0x5a0 kernel/printk/printk.c:2303 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+0x4ac/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 expire_timers kernel/time/timer.c:1830 [inline] __run_timers+0x8ec/0xaf0 kernel/time/timer.c:2417 __run_timer_base kernel/time/timer.c:2428 [inline] __run_timer_base kernel/time/timer.c:2421 [inline] run_timer_base+0x111/0x190 kernel/time/timer.c:2437 run_timer_softirq+0x1a/0x40 kernel/time/timer.c:2447 handle_softirqs+0x216/0x8f0 kernel/softirq.c:554 __do_softirq kernel/softirq.c:588 [inline] invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu kernel/softirq.c:637 [inline] irq_exit_rcu+0xbb/0x120 kernel/softirq.c:649 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline] sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1043 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline] arch_safe_halt arch/x86/include/asm/irqflags.h:86 [inline] default_idle+0xf/0x20 arch/x86/kernel/process.c:742 default_idle_call+0x6d/0xb0 kernel/sched/idle.c:117 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x32c/0x3f0 kernel/sched/idle.c:332 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430 rest_init+0x16b/0x2b0 init/main.c:747 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 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 *** 1 lock held by swapper/0/0: #0: ffff88802c02a858 (&base->lock){-.-.}-{2:2}, at: __run_timer_base kernel/time/timer.c:2427 [inline] #0: ffff88802c02a858 (&base->lock){-.-.}-{2:2}, at: __run_timer_base kernel/time/timer.c:2421 [inline] #0: ffff88802c02a858 (&base->lock){-.-.}-{2:2}, at: run_timer_base+0x109/0x190 kernel/time/timer.c:2437 stack backtrace: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.9.0-syzkaller-10713-g2a8120d7b482 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114 check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2187 check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3869 [inline] __lock_acquire+0x2478/0x3b30 kernel/locking/lockdep.c:5137 lock_acquire kernel/locking/lockdep.c:5754 [inline] lock_acquire+0x1b1/0x560 kernel/locking/lockdep.c:5719 __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:2684 [inline] console_trylock_spinning kernel/printk/printk.c:1958 [inline] vprintk_emit kernel/printk/printk.c:2347 [inline] vprintk_emit+0xe4/0x5a0 kernel/printk/printk.c:2303 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+0x4ac/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:expire_timers kernel/time/timer.c:1830 [inline] RIP: 0010:__run_timers+0x8ec/0xaf0 kernel/time/timer.c:2417 Code: 6e 48 e8 77 34 13 00 89 de 31 ff 83 eb 01 e8 6b 2f 13 00 8b 44 24 18 85 c0 0f 85 18 fc ff ff e9 91 fb ff ff e8 55 34 13 00 90 <0f> 0b 90 e9 7b fc ff ff e8 47 34 13 00 90 0f 0b 90 e9 04 fd ff ff RSP: 0018:ffffc90000007d58 EFLAGS: 00010046 RAX: 0000000000000000 RBX: ffffe8ffad07be10 RCX: ffffffff817b4d49 RDX: ffffffff8d8957c0 RSI: ffffffff817b4ddb RDI: ffffe8ffad07be28 RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: ffffc90000007e10 R13: ffffc90000007e10 R14: ffff88802c02a840 R15: dffffc0000000000 __run_timer_base kernel/time/timer.c:2428 [inline] __run_timer_base kernel/time/timer.c:2421 [inline] run_timer_base+0x111/0x190 kernel/time/timer.c:2437 run_timer_softirq+0x1a/0x40 kernel/time/timer.c:2447 handle_softirqs+0x216/0x8f0 kernel/softirq.c:554 __do_softirq kernel/softirq.c:588 [inline] invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu kernel/softirq.c:637 [inline] irq_exit_rcu+0xbb/0x120 kernel/softirq.c:649 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline] sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1043 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 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:default_idle+0xf/0x20 arch/x86/kernel/process.c:743 Code: 4c 01 c7 4c 29 c2 e9 72 ff ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d c3 36 48 00 fb f4 c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 RSP: 0018:ffffffff8d807e20 EFLAGS: 00000246 RAX: 0000000000140011 RBX: 0000000000000000 RCX: ffffffff8ade3e29 RDX: 0000000000000000 RSI: ffffffff8b2cb6c0 RDI: ffffffff8b8fae60 RBP: fffffbfff1b12af8 R08: 0000000000000001 R09: ffffed1005806fe5 R10: ffff88802c037f2b R11: 0000000000000000 R12: 0000000000000000 R13: ffffffff8d8957c0 R14: ffffffff8fe29810 R15: 0000000000000000 default_idle_call+0x6d/0xb0 kernel/sched/idle.c:117 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x32c/0x3f0 kernel/sched/idle.c:332 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430 rest_init+0x16b/0x2b0 init/main.c:747 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 WARNING: CPU: 0 PID: 0 at kernel/time/timer.c:1830 expire_timers kernel/time/timer.c:1830 [inline] WARNING: CPU: 0 PID: 0 at kernel/time/timer.c:1830 __run_timers+0x8ec/0xaf0 kernel/time/timer.c:2417 Modules linked in: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.9.0-syzkaller-10713-g2a8120d7b482 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 RIP: 0010:expire_timers kernel/time/timer.c:1830 [inline] RIP: 0010:__run_timers+0x8ec/0xaf0 kernel/time/timer.c:2417 Code: 6e 48 e8 77 34 13 00 89 de 31 ff 83 eb 01 e8 6b 2f 13 00 8b 44 24 18 85 c0 0f 85 18 fc ff ff e9 91 fb ff ff e8 55 34 13 00 90 <0f> 0b 90 e9 7b fc ff ff e8 47 34 13 00 90 0f 0b 90 e9 04 fd ff ff RSP: 0018:ffffc90000007d58 EFLAGS: 00010046 RAX: 0000000000000000 RBX: ffffe8ffad07be10 RCX: ffffffff817b4d49 RDX: ffffffff8d8957c0 RSI: ffffffff817b4ddb RDI: ffffe8ffad07be28 RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: ffffc90000007e10 R13: ffffc90000007e10 R14: ffff88802c02a840 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff88802c000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000f7493f1c CR3: 0000000054c9e000 CR4: 0000000000350ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __run_timer_base kernel/time/timer.c:2428 [inline] __run_timer_base kernel/time/timer.c:2421 [inline] run_timer_base+0x111/0x190 kernel/time/timer.c:2437 run_timer_softirq+0x1a/0x40 kernel/time/timer.c:2447 handle_softirqs+0x216/0x8f0 kernel/softirq.c:554 __do_softirq kernel/softirq.c:588 [inline] invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu kernel/softirq.c:637 [inline] irq_exit_rcu+0xbb/0x120 kernel/softirq.c:649 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline] sysvec_apic_timer_interrupt+0x95/0xb0 arch/x86/kernel/apic/apic.c:1043 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 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:default_idle+0xf/0x20 arch/x86/kernel/process.c:743 Code: 4c 01 c7 4c 29 c2 e9 72 ff ff ff 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d c3 36 48 00 fb f4 c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 RSP: 0018:ffffffff8d807e20 EFLAGS: 00000246 RAX: 0000000000140011 RBX: 0000000000000000 RCX: ffffffff8ade3e29 RDX: 0000000000000000 RSI: ffffffff8b2cb6c0 RDI: ffffffff8b8fae60 RBP: fffffbfff1b12af8 R08: 0000000000000001 R09: ffffed1005806fe5 R10: ffff88802c037f2b R11: 0000000000000000 R12: 0000000000000000 R13: ffffffff8d8957c0 R14: ffffffff8fe29810 R15: 0000000000000000 default_idle_call+0x6d/0xb0 kernel/sched/idle.c:117 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x32c/0x3f0 kernel/sched/idle.c:332 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:430 rest_init+0x16b/0x2b0 init/main.c:747 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 ---------------- Code disassembly (best guess): 0: 4c 01 c7 add %r8,%rdi 3: 4c 29 c2 sub %r8,%rdx 6: e9 72 ff ff ff jmp 0xffffff7d b: 90 nop c: 90 nop d: 90 nop e: 90 nop f: 90 nop 10: 90 nop 11: 90 nop 12: 90 nop 13: 90 nop 14: 90 nop 15: 90 nop 16: 90 nop 17: 90 nop 18: 90 nop 19: 90 nop 1a: 90 nop 1b: f3 0f 1e fa endbr64 1f: 66 90 xchg %ax,%ax 21: 0f 00 2d c3 36 48 00 verw 0x4836c3(%rip) # 0x4836eb 28: fb sti 29: f4 hlt * 2a: fa cli <-- trapping instruction 2b: c3 ret 2c: cc int3 2d: cc int3 2e: cc int3 2f: cc int3 30: 66 66 2e 0f 1f 84 00 data16 cs nopw 0x0(%rax,%rax,1) 37: 00 00 00 00 3b: 90 nop 3c: 90 nop 3d: 90 nop 3e: 90 nop 3f: 90 nop