dl_rq->running_bw > dl_rq->this_bw ------------[ cut here ]------------ WARNING: CPU: 0 PID: 13026 at kernel/sched/deadline.c:125 sub_rq_bw kernel/sched/deadline.c:125 [inline] WARNING: CPU: 0 PID: 13026 at kernel/sched/deadline.c:125 switched_from_dl.cold.25+0x5b/0x62 kernel/sched/deadline.c:2232 Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 13026 Comm: syz-executor4 Not tainted 4.14.67+ #1 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+0x148/0x185 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:2232 RSP: 0018:ffff8801d6237d18 EFLAGS: 00010082 RAX: 0000000000000022 RBX: ffff8801d08b9780 RCX: 0000000000010948 RDX: 0000000000000000 RSI: ffffc90005b2a000 RDI: 0000000000000000 RBP: ffff8801dbb2a240 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801d08b97dc R13: 0000000000000000 R14: ffff8801dbb2ab50 R15: 0000000000099179 check_class_changed kernel/sched/core.c:871 [inline] __sched_setscheduler+0x9a1/0x2800 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: 0033:0x457089 RSP: 002b:00007fc467ec2c78 EFLAGS: 00000246 ORIG_RAX: 000000000000013a RAX: ffffffffffffffda RBX: 00007fc467ec36d4 RCX: 0000000000457089 RDX: 0000000000000000 RSI: 0000000020000040 RDI: 00000000000024c7 RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d3f70 R14: 00000000004c88d5 R15: 0000000000000000 ====================================================== WARNING: possible circular locking dependency detected 4.14.67+ #1 Not tainted ------------------------------------------------------ syz-executor4/13026 is trying to acquire lock: ((console_sem).lock){-.-.}, at: [] down_trylock+0xe/0x70 kernel/locking/semaphore.c:136 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: -> #2 (&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:1835 [inline] task_fork_fair+0x59/0x590 kernel/sched/fair.c:11391 sched_fork+0x48b/0xd30 kernel/sched/core.c:2459 copy_process.part.6+0x120d/0x6490 kernel/fork.c:1730 copy_process kernel/fork.c:1571 [inline] _do_fork+0x1c2/0xd50 kernel/fork.c:2052 kernel_thread+0x2f/0x40 kernel/fork.c:2116 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:239 -> #1 (&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 up+0x8d/0xd0 kernel/locking/semaphore.c:187 __up_console_sem+0x44/0x90 kernel/printk/printk.c:245 console_unlock+0x451/0xb50 kernel/printk/printk.c:2248 vprintk_emit+0x241/0x4e0 kernel/printk/printk.c:1757 vprintk_func+0x58/0x136 kernel/printk/printk_safe.c:385 printk+0xa7/0xcf kernel/printk/printk.c:1829 fat_msg+0xdc/0x110 fs/fat/misc.c:54 parse_options.cold.14+0x4a/0x71 fs/fat/inode.c:1340 fat_fill_super+0x276/0x3270 fs/fat/inode.c:1626 mount_bdev+0x2ab/0x370 fs/super.c:1149 mount_fs+0x28f/0x31a fs/super.c:1255 vfs_kern_mount.part.9+0xce/0x4a0 fs/namespace.c:1056 vfs_kern_mount fs/namespace.c:1038 [inline] do_new_mount fs/namespace.c:2561 [inline] do_mount+0x404/0x26e0 fs/namespace.c:2891 SYSC_mount fs/namespace.c:3107 [inline] SyS_mount+0xe5/0x100 fs/namespace.c:3084 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289 entry_SYSCALL_64_after_hwframe+0x42/0xb7 -> #0 ((console_sem).lock){-.-.}: 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 down_trylock+0xe/0x70 kernel/locking/semaphore.c:136 __down_trylock_console_sem+0x33/0xc0 kernel/printk/printk.c:228 console_trylock+0x13/0xf0 kernel/printk/printk.c:2065 vprintk_emit+0x233/0x4e0 kernel/printk/printk.c:1756 vprintk_func+0x58/0x136 kernel/printk/printk_safe.c:385 printk+0xa7/0xcf kernel/printk/printk.c:1829 sub_rq_bw kernel/sched/deadline.c:125 [inline] switched_from_dl.cold.25+0x5b/0x62 kernel/sched/deadline.c:2232 check_class_changed kernel/sched/core.c:871 [inline] __sched_setscheduler+0x9a1/0x2800 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: (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 *** 3 locks held by syz-executor4/13026: #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 stack backtrace: CPU: 0 PID: 13026 Comm: syz-executor4 Not tainted 4.14.67+ #1 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 down_trylock+0xe/0x70 kernel/locking/semaphore.c:136 __down_trylock_console_sem+0x33/0xc0 kernel/printk/printk.c:228 console_trylock+0x13/0xf0 kernel/printk/printk.c:2065 vprintk_emit+0x233/0x4e0 kernel/printk/printk.c:1756 vprintk_func+0x58/0x136 kernel/printk/printk_safe.c:385 printk+0xa7/0xcf kernel/printk/printk.c:1829 sub_rq_bw kernel/sched/deadline.c:125 [inline] switched_from_dl.cold.25+0x5b/0x62 kernel/sched/deadline.c:2232 check_class_changed kernel/sched/core.c:871 [inline] __sched_setscheduler+0x9a1/0x2800 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: 0033:0x457089 RSP: 002b:00007fc467ec2c78 EFLAGS: 00000246 ORIG_RAX: 000000000000013a RAX: ffffffffffffffda RBX: 00007fc467ec36d4 RCX: 0000000000457089 RDX: 0000000000000000 RSI: 0000000020000040 RDI: 00000000000024c7 RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d3f70 R14: 00000000004c88d5 R15: 0000000000000000 Shutting down cpus with NMI Dumping ftrace buffer: (ftrace buffer empty) Kernel Offset: 0x2b200000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) Rebooting in 86400 seconds..