EEVDF scheduling fail, picking leftmost ====================================================== WARNING: possible circular locking dependency detected 6.6.0-rc4-next-20231004-syzkaller #0 Not tainted ------------------------------------------------------ kworker/0:1/9 is trying to acquire lock: ffffffff8cab8520 (console_owner){....}-{0:0}, at: console_trylock_spinning kernel/printk/printk.c:1963 [inline] ffffffff8cab8520 (console_owner){....}-{0:0}, at: vprintk_emit+0x313/0x5f0 kernel/printk/printk.c:2303 but task is already holding lock: ffff8880b983c718 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:558 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #5 (&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:558 raw_spin_rq_lock kernel/sched/sched.h:1357 [inline] rq_lock kernel/sched/sched.h:1671 [inline] task_fork_fair+0x70/0x240 kernel/sched/fair.c:12399 sched_cgroup_fork+0x3cf/0x510 kernel/sched/core.c:4799 copy_process+0x4580/0x74b0 kernel/fork.c:2609 kernel_clone+0xfd/0x920 kernel/fork.c:2907 user_mode_thread+0xb4/0xf0 kernel/fork.c:2985 rest_init+0x27/0x2b0 init/main.c:691 arch_call_rest_init+0x13/0x30 init/main.c:823 start_kernel+0x39f/0x480 init/main.c:1068 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:556 x86_64_start_kernel+0xb2/0xc0 arch/x86/kernel/head64.c:537 secondary_startup_64_no_verify+0x166/0x16b -> #4 (&p->pi_lock){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x50 kernel/locking/spinlock.c:162 class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:518 [inline] try_to_wake_up+0xb0/0x15d0 kernel/sched/core.c:4213 kick_pool+0x253/0x460 kernel/workqueue.c:1142 create_worker+0x45e/0x710 kernel/workqueue.c:2217 workqueue_init+0x319/0x830 kernel/workqueue.c:6680 kernel_init_freeable+0x332/0x900 init/main.c:1532 kernel_init+0x1c/0x2a0 init/main.c:1437 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304 -> #3 (&pool->lock){-.-.}-{2:2}: __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 __queue_work+0x399/0x1050 kernel/workqueue.c:1763 queue_work_on+0xed/0x110 kernel/workqueue.c:1834 queue_work include/linux/workqueue.h:554 [inline] rpm_suspend+0x1219/0x16f0 drivers/base/power/runtime.c:660 rpm_idle+0x574/0x6e0 drivers/base/power/runtime.c:534 __pm_runtime_idle+0xbe/0x160 drivers/base/power/runtime.c:1102 pm_runtime_put include/linux/pm_runtime.h:460 [inline] __device_attach+0x382/0x4b0 drivers/base/dd.c:1048 bus_probe_device+0x17c/0x1c0 drivers/base/bus.c:532 device_add+0x117e/0x1aa0 drivers/base/core.c:3624 serial_base_port_add+0x353/0x4b0 drivers/tty/serial/serial_base_bus.c:178 serial_core_port_device_add drivers/tty/serial/serial_core.c:3315 [inline] serial_core_register_port+0x137/0x1af0 drivers/tty/serial/serial_core.c:3356 serial8250_register_8250_port+0x140d/0x2080 drivers/tty/serial/8250/8250_core.c:1139 serial_pnp_probe+0x47d/0x880 drivers/tty/serial/8250/8250_pnp.c:478 pnp_device_probe+0x2a3/0x4c0 drivers/pnp/driver.c:111 call_driver_probe drivers/base/dd.c:579 [inline] really_probe+0x234/0xc90 drivers/base/dd.c:658 __driver_probe_device+0x1de/0x4b0 drivers/base/dd.c:800 driver_probe_device+0x4c/0x1a0 drivers/base/dd.c:830 __driver_attach+0x274/0x570 drivers/base/dd.c:1216 bus_for_each_dev+0x13c/0x1d0 drivers/base/bus.c:368 bus_add_driver+0x2e9/0x630 drivers/base/bus.c:673 driver_register+0x15c/0x4a0 drivers/base/driver.c:246 serial8250_init+0xba/0x4b0 drivers/tty/serial/8250/8250_core.c:1240 do_one_initcall+0x11c/0x640 init/main.c:1232 do_initcall_level init/main.c:1294 [inline] do_initcalls init/main.c:1310 [inline] do_basic_setup init/main.c:1329 [inline] kernel_init_freeable+0x5c2/0x900 init/main.c:1547 kernel_init+0x1c/0x2a0 init/main.c:1437 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304 -> #2 (&dev->power.lock){-...}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x50 kernel/locking/spinlock.c:162 __pm_runtime_resume+0xab/0x170 drivers/base/power/runtime.c:1169 pm_runtime_get include/linux/pm_runtime.h:408 [inline] __uart_start+0x1b0/0x420 drivers/tty/serial/serial_core.c:148 uart_write+0x2ff/0x5b0 drivers/tty/serial/serial_core.c:618 process_output_block drivers/tty/n_tty.c:579 [inline] n_tty_write+0x422/0x1130 drivers/tty/n_tty.c:2384 iterate_tty_write drivers/tty/tty_io.c:1017 [inline] file_tty_write.constprop.0+0x519/0x9b0 drivers/tty/tty_io.c:1088 tty_write drivers/tty/tty_io.c:1109 [inline] redirected_tty_write drivers/tty/tty_io.c:1132 [inline] redirected_tty_write+0xa6/0xc0 drivers/tty/tty_io.c:1112 call_write_iter include/linux/fs.h:1960 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x64f/0xe40 fs/read_write.c:584 ksys_write+0x12f/0x250 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #1 (&port_lock_key){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x50 kernel/locking/spinlock.c:162 uart_port_lock_irqsave include/linux/serial_core.h:616 [inline] serial8250_console_write+0xa7c/0x1060 drivers/tty/serial/8250/8250_port.c:3410 console_emit_next_record kernel/printk/printk.c:2894 [inline] console_flush_all+0x4d5/0xd50 kernel/printk/printk.c:2960 console_unlock+0x10c/0x260 kernel/printk/printk.c:3029 vprintk_emit+0x17f/0x5f0 kernel/printk/printk.c:2304 vprintk+0x7b/0x90 kernel/printk/printk_safe.c:45 _printk+0xc8/0x100 kernel/printk/printk.c:2329 register_console+0xb30/0x1210 kernel/printk/printk.c:3535 univ8250_console_init+0x35/0x50 drivers/tty/serial/8250/8250_core.c:717 console_init+0xba/0x5c0 kernel/printk/printk.c:3681 start_kernel+0x25a/0x480 init/main.c:1004 x86_64_start_reservations+0x18/0x30 arch/x86/kernel/head64.c:556 x86_64_start_kernel+0xb2/0xc0 arch/x86/kernel/head64.c:537 secondary_startup_64_no_verify+0x166/0x16b -> #0 (console_owner){....}-{0:0}: check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain kernel/locking/lockdep.c:3868 [inline] __lock_acquire+0x2e3d/0x5de0 kernel/locking/lockdep.c:5136 lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5718 console_trylock_spinning kernel/printk/printk.c:1963 [inline] vprintk_emit+0x328/0x5f0 kernel/printk/printk.c:2303 vprintk+0x7b/0x90 kernel/printk/printk_safe.c:45 _printk+0xc8/0x100 kernel/printk/printk.c:2329 pick_eevdf kernel/sched/fair.c:963 [inline] pick_next_entity kernel/sched/fair.c:5247 [inline] pick_next_task_fair+0x1c5/0x1280 kernel/sched/fair.c:8205 __pick_next_task kernel/sched/core.c:5986 [inline] pick_next_task kernel/sched/core.c:6061 [inline] __schedule+0x493/0x5a00 kernel/sched/core.c:6640 __schedule_loop kernel/sched/core.c:6753 [inline] schedule+0xe7/0x270 kernel/sched/core.c:6768 worker_thread+0x2e1/0x1290 kernel/workqueue.c:2799 kthread+0x33c/0x440 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304 other info that might help us debug this: Chain exists of: console_owner --> &p->pi_lock --> &rq->__lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&rq->__lock); lock(&p->pi_lock); lock(&rq->__lock); lock(console_owner); *** DEADLOCK *** 1 lock held by kworker/0:1/9: #0: ffff8880b983c718 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x29/0x130 kernel/sched/core.c:558 stack backtrace: CPU: 0 PID: 9 Comm: kworker/0:1 Not tainted 6.6.0-rc4-next-20231004-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023 Workqueue: 0x0 (events_power_efficient) Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106 check_noncircular+0x311/0x3f0 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:3868 [inline] __lock_acquire+0x2e3d/0x5de0 kernel/locking/lockdep.c:5136 lock_acquire kernel/locking/lockdep.c:5753 [inline] lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5718 console_trylock_spinning kernel/printk/printk.c:1963 [inline] vprintk_emit+0x328/0x5f0 kernel/printk/printk.c:2303 vprintk+0x7b/0x90 kernel/printk/printk_safe.c:45 _printk+0xc8/0x100 kernel/printk/printk.c:2329 pick_eevdf kernel/sched/fair.c:963 [inline] pick_next_entity kernel/sched/fair.c:5247 [inline] pick_next_task_fair+0x1c5/0x1280 kernel/sched/fair.c:8205 __pick_next_task kernel/sched/core.c:5986 [inline] pick_next_task kernel/sched/core.c:6061 [inline] __schedule+0x493/0x5a00 kernel/sched/core.c:6640 __schedule_loop kernel/sched/core.c:6753 [inline] schedule+0xe7/0x270 kernel/sched/core.c:6768 worker_thread+0x2e1/0x1290 kernel/workqueue.c:2799 kthread+0x33c/0x440 kernel/kthread.c:388 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304