dl_rq->running_bw > dl_rq->this_bw ------------[ cut here ]------------ WARNING: CPU: 0 PID: 773 at kernel/sched/deadline.c:125 sub_rq_bw kernel/sched/deadline.c:125 [inline] WARNING: CPU: 0 PID: 773 at kernel/sched/deadline.c:125 switched_from_dl.cold.25+0x5b/0x62 kernel/sched/deadline.c:2236 Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 773 Comm: syz-executor4 Not tainted 4.14.84+ #14 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0xb9/0x11b lib/dump_stack.c:53 panic+0x1bf/0x3a4 kernel/panic.c:181 __warn.cold.7+0x2f/0x35 kernel/panic.c:542 report_bug+0x1f7/0x26c lib/bug.c:186 fixup_bug arch/x86/kernel/traps.c:177 [inline] do_error_trap+0x1ba/0x2c0 arch/x86/kernel/traps.c:295 invalid_op+0x18/0x40 arch/x86/entry/entry_64.S:944 RIP: 0010:sub_rq_bw kernel/sched/deadline.c:125 [inline] RIP: 0010:switched_from_dl.cold.25+0x5b/0x62 kernel/sched/deadline.c:2236 RSP: 0018:ffff88819e987d18 EFLAGS: 00010082 RAX: 0000000000000022 RBX: ffff8881c9da5e00 RCX: 0000000000000235 RDX: 0000000000000000 RSI: ffffc90003589000 RDI: ffffffff96fd23e0 RBP: ffff8881dba2a240 R08: 0000000000000001 R09: 0000000000000000 R10: ffff8881cb7c37a8 R11: 0000000000000001 R12: ffff8881c9da5e5c R13: 0000000000000000 R14: ffff8881dba2ab50 R15: 00000000000991a9 check_class_changed kernel/sched/core.c:871 [inline] __sched_setscheduler+0x9a1/0x27c0 kernel/sched/core.c:4295 sched_setattr kernel/sched/core.c:4348 [inline] SYSC_sched_setattr kernel/sched/core.c:4519 [inline] SyS_sched_setattr+0x22c/0x370 kernel/sched/core.c:4498 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x457569 RSP: 002b:00007f2850733c78 EFLAGS: 00000246 ORIG_RAX: 000000000000013a RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457569 RDX: 0000000000000000 RSI: 0000000020000040 RDI: 0000000000001718 RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f28507346d4 R13: 00000000004c3af5 R14: 00000000004d61a8 R15: 00000000ffffffff ====================================================== WARNING: possible circular locking dependency detected 4.14.84+ #14 Not tainted ------------------------------------------------------ syz-executor4/773 is trying to acquire lock: (&port_lock_key){-.-.}, at: [] serial8250_console_write+0x6af/0x800 drivers/tty/serial/8250/8250_port.c:3232 but task is already holding lock: (&rq->lock){-.-.}, at: [] task_rq_lock+0xc9/0x340 kernel/sched/core.c:126 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&rq->lock){-.-.}: __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:152 rq_lock kernel/sched/sched.h:1837 [inline] task_fork_fair+0x59/0x590 kernel/sched/fair.c:11442 sched_fork+0x48b/0xd30 kernel/sched/core.c:2459 copy_process.part.6+0x120d/0x6530 kernel/fork.c:1732 copy_process kernel/fork.c:1573 [inline] _do_fork+0x1c2/0xd50 kernel/fork.c:2054 kernel_thread+0x2f/0x40 kernel/fork.c:2118 rest_init+0x22/0x2a0 init/main.c:401 start_kernel+0x6fb/0x739 init/main.c:710 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:240 -> #2 (&p->pi_lock){-.-.}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x41/0x50 kernel/locking/spinlock.c:160 try_to_wake_up+0x95/0x1230 kernel/sched/core.c:2030 autoremove_wake_function+0x12/0x140 kernel/sched/wait.c:377 __wake_up_common+0x109/0x5a0 kernel/sched/wait.c:97 __wake_up_common_lock+0xc5/0x120 kernel/sched/wait.c:125 tty_port_default_wakeup+0x26/0x40 drivers/tty/tty_port.c:49 serial8250_tx_chars+0x417/0xa70 drivers/tty/serial/8250/8250_port.c:1810 serial8250_handle_irq.part.15+0x1b1/0x1f0 drivers/tty/serial/8250/8250_port.c:1883 serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1869 [inline] serial8250_default_handle_irq+0x9b/0x110 drivers/tty/serial/8250/8250_port.c:1899 serial8250_interrupt+0xea/0x1a0 drivers/tty/serial/8250/8250_core.c:129 __handle_irq_event_percpu+0xf8/0x770 kernel/irq/handle.c:147 handle_irq_event_percpu+0x76/0x150 kernel/irq/handle.c:187 handle_irq_event+0xa1/0x12d kernel/irq/handle.c:204 handle_edge_irq+0x1f0/0x7f0 kernel/irq/chip.c:770 generic_handle_irq_desc include/linux/irqdesc.h:158 [inline] handle_irq+0x242/0x328 arch/x86/kernel/irq_64.c:78 do_IRQ+0x7d/0x1b0 arch/x86/kernel/irq.c:230 ret_from_intr+0x0/0x22 native_safe_halt+0x2/0x10 arch/x86/include/asm/irqflags.h:57 arch_safe_halt arch/x86/include/asm/paravirt.h:94 [inline] default_idle+0x50/0x380 arch/x86/kernel/process.c:501 cpuidle_idle_call kernel/sched/idle.c:159 [inline] do_idle+0x2da/0x3b0 kernel/sched/idle.c:268 cpu_startup_entry+0xc9/0xe0 kernel/sched/idle.c:374 start_kernel+0x6fb/0x739 init/main.c:710 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:240 -> #1 (&tty->write_wait){-.-.}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x41/0x50 kernel/locking/spinlock.c:160 __wake_up_common_lock+0xaa/0x120 kernel/sched/wait.c:124 tty_port_default_wakeup+0x26/0x40 drivers/tty/tty_port.c:49 serial8250_tx_chars+0x417/0xa70 drivers/tty/serial/8250/8250_port.c:1810 serial8250_handle_irq.part.15+0x1b1/0x1f0 drivers/tty/serial/8250/8250_port.c:1883 serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1869 [inline] serial8250_default_handle_irq+0x9b/0x110 drivers/tty/serial/8250/8250_port.c:1899 serial8250_interrupt+0xea/0x1a0 drivers/tty/serial/8250/8250_core.c:129 __handle_irq_event_percpu+0xf8/0x770 kernel/irq/handle.c:147 handle_irq_event_percpu+0x76/0x150 kernel/irq/handle.c:187 handle_irq_event+0xa1/0x12d kernel/irq/handle.c:204 handle_edge_irq+0x1f0/0x7f0 kernel/irq/chip.c:770 generic_handle_irq_desc include/linux/irqdesc.h:158 [inline] handle_irq+0x242/0x328 arch/x86/kernel/irq_64.c:78 do_IRQ+0x7d/0x1b0 arch/x86/kernel/irq.c:230 ret_from_intr+0x0/0x22 native_safe_halt+0x2/0x10 arch/x86/include/asm/irqflags.h:57 arch_safe_halt arch/x86/include/asm/paravirt.h:94 [inline] default_idle+0x50/0x380 arch/x86/kernel/process.c:501 cpuidle_idle_call kernel/sched/idle.c:159 [inline] do_idle+0x2da/0x3b0 kernel/sched/idle.c:268 cpu_startup_entry+0xc9/0xe0 kernel/sched/idle.c:374 start_kernel+0x6fb/0x739 init/main.c:710 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:240 -> #0 (&port_lock_key){-.-.}: lock_acquire+0x10f/0x380 kernel/locking/lockdep.c:3991 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x41/0x50 kernel/locking/spinlock.c:160 serial8250_console_write+0x6af/0x800 drivers/tty/serial/8250/8250_port.c:3232 call_console_drivers kernel/printk/printk.c:1579 [inline] console_unlock+0x5b9/0xb50 kernel/printk/printk.c:2241 vprintk_emit+0x142/0x180 kernel/printk/printk.c:1777 vprintk_func+0x58/0x159 kernel/printk/printk_safe.c:401 printk+0xa7/0xcf kernel/printk/printk.c:1850 __warn+0x36/0x1b0 kernel/panic.c:521 report_bug+0x1f7/0x26c lib/bug.c:186 fixup_bug arch/x86/kernel/traps.c:177 [inline] do_error_trap+0x1ba/0x2c0 arch/x86/kernel/traps.c:295 invalid_op+0x18/0x40 arch/x86/entry/entry_64.S:944 sub_rq_bw kernel/sched/deadline.c:125 [inline] switched_from_dl.cold.25+0x5b/0x62 kernel/sched/deadline.c:2236 check_class_changed kernel/sched/core.c:871 [inline] __sched_setscheduler+0x9a1/0x27c0 kernel/sched/core.c:4295 sched_setattr kernel/sched/core.c:4348 [inline] SYSC_sched_setattr kernel/sched/core.c:4519 [inline] SyS_sched_setattr+0x22c/0x370 kernel/sched/core.c:4498 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 other info that might help us debug this: Chain exists of: &port_lock_key --> &p->pi_lock --> &rq->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&rq->lock); lock(&p->pi_lock); lock(&rq->lock); lock(&port_lock_key); *** DEADLOCK *** 4 locks held by syz-executor4/773: #0: (rcu_read_lock){....}, at: [] SYSC_sched_setattr kernel/sched/core.c:4512 [inline] #0: (rcu_read_lock){....}, at: [] SyS_sched_setattr+0x1c0/0x370 kernel/sched/core.c:4498 #1: (&p->pi_lock){-.-.}, at: [] task_rq_lock+0x68/0x340 kernel/sched/core.c:124 #2: (&rq->lock){-.-.}, at: [] task_rq_lock+0xc9/0x340 kernel/sched/core.c:126 #3: (console_lock){+.+.}, at: [] vprintk_emit+0x10e/0x180 kernel/printk/printk.c:1776 stack backtrace: CPU: 0 PID: 773 Comm: syz-executor4 Not tainted 4.14.84+ #14 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0xb9/0x11b lib/dump_stack.c:53 print_circular_bug.isra.18.cold.43+0x2d3/0x40c kernel/locking/lockdep.c:1258 check_prev_add kernel/locking/lockdep.c:1901 [inline] check_prevs_add kernel/locking/lockdep.c:2018 [inline] validate_chain kernel/locking/lockdep.c:2460 [inline] __lock_acquire+0x2ff9/0x4320 kernel/locking/lockdep.c:3487 lock_acquire+0x10f/0x380 kernel/locking/lockdep.c:3991 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x41/0x50 kernel/locking/spinlock.c:160 serial8250_console_write+0x6af/0x800 drivers/tty/serial/8250/8250_port.c:3232 call_console_drivers kernel/printk/printk.c:1579 [inline] console_unlock+0x5b9/0xb50 kernel/printk/printk.c:2241 vprintk_emit+0x142/0x180 kernel/printk/printk.c:1777 vprintk_func+0x58/0x159 kernel/printk/printk_safe.c:401 printk+0xa7/0xcf kernel/printk/printk.c:1850 __warn+0x36/0x1b0 kernel/panic.c:521 report_bug+0x1f7/0x26c lib/bug.c:186 fixup_bug arch/x86/kernel/traps.c:177 [inline] do_error_trap+0x1ba/0x2c0 arch/x86/kernel/traps.c:295 invalid_op+0x18/0x40 arch/x86/entry/entry_64.S:944 RIP: 0010:sub_rq_bw kernel/sched/deadline.c:125 [inline] RIP: 0010:switched_from_dl.cold.25+0x5b/0x62 kernel/sched/deadline.c:2236 RSP: 0018:ffff88819e987d18 EFLAGS: 00010082 RAX: 0000000000000022 RBX: ffff8881c9da5e00 RCX: 0000000000000235 RDX: 0000000000000000 RSI: ffffc90003589000 RDI: ffffffff96fd23e0 RBP: ffff8881dba2a240 R08: 0000000000000001 R09: 0000000000000000 R10: ffff8881cb7c37a8 R11: 0000000000000001 R12: ffff8881c9da5e5c R13: 0000000000000000 R14: ffff8881dba2ab50 R15: 00000000000991a9 check_class_changed kernel/sched/core.c:871 [inline] __sched_setscheduler+0x9a1/0x27c0 kernel/sched/core.c:4295 sched_setattr kernel/sched/core.c:4348 [inline] SYSC_sched_setattr kernel/sched/core.c:4519 [inline] SyS_sched_setattr+0x22c/0x370 kernel/sched/core.c:4498 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x457569 RSP: 002b:00007f2850733c78 EFLAGS: 00000246 ORIG_RAX: 000000000000013a RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457569 RDX: 0000000000000000 RSI: 0000000020000040 RDI: 0000000000001718 RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f28507346d4 R13: 00000000004c3af5 R14: 00000000004d61a8 R15: 00000000ffffffff Shutting down cpus with NMI Kernel Offset: 0x12600000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) Rebooting in 86400 seconds..