EEVDF scheduling fail, picking leftmost ====================================================== WARNING: possible circular locking dependency detected 6.6.0-rc4-next-20231005-syzkaller-09984-g7d730f1bf6f3 #0 Not tainted ------------------------------------------------------ udevd/4500 is trying to acquire lock: ffffffff8d5205c0 (console_owner){....}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:303 [inline] ffffffff8d5205c0 (console_owner){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:232 [inline] ffffffff8d5205c0 (console_owner){....}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:286 [inline] ffffffff8d5205c0 (console_owner){....}-{0:0}, at: console_flush_all+0x154/0xec0 kernel/printk/printk.c:2952 but task is already holding lock: ffff8880b993c318 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:558 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #4 (&rq->__lock){-.-.}-{2:2}: _raw_spin_lock_nested+0x31/0x40 kernel/locking/spinlock.c:378 raw_spin_rq_lock_nested+0x2a/0x140 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+0x61/0x1e0 kernel/sched/fair.c:12399 sched_cgroup_fork+0x37b/0x410 kernel/sched/core.c:4799 copy_process+0x27b0/0x3fb0 kernel/fork.c:2609 kernel_clone+0x222/0x840 kernel/fork.c:2907 user_mode_thread+0x132/0x190 kernel/fork.c:2985 rest_init+0x27/0x300 init/main.c:691 arch_call_rest_init+0xe/0x10 init/main.c:823 start_kernel+0x46e/0x4f0 init/main.c:1068 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:556 x86_64_start_kernel+0x99/0xa0 arch/x86/kernel/head64.c:537 secondary_startup_64_no_verify+0x167/0x16b -> #3 (&p->pi_lock){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:518 [inline] try_to_wake_up+0xb5/0x1440 kernel/sched/core.c:4213 __wake_up_common+0x2a0/0x4e0 kernel/sched/wait.c:107 __wake_up_common_lock kernel/sched/wait.c:138 [inline] __wake_up+0x11e/0x1d0 kernel/sched/wait.c:160 tty_port_default_wakeup+0xa6/0xf0 drivers/tty/tty_port.c:69 serial8250_tx_chars+0x6b7/0x8b0 drivers/tty/serial/8250/8250_port.c:1842 serial8250_handle_irq+0x549/0x700 drivers/tty/serial/8250/8250_port.c:1949 serial8250_default_handle_irq+0xcc/0x1e0 drivers/tty/serial/8250/8250_port.c:1969 serial8250_interrupt+0xa5/0x1e0 drivers/tty/serial/8250/8250_core.c:127 __handle_irq_event_percpu+0x286/0xa20 kernel/irq/handle.c:158 handle_irq_event_percpu kernel/irq/handle.c:193 [inline] handle_irq_event+0x89/0x1f0 kernel/irq/handle.c:210 handle_edge_irq+0x249/0xbf0 kernel/irq/chip.c:831 generic_handle_irq_desc include/linux/irqdesc.h:161 [inline] handle_irq arch/x86/kernel/irq.c:238 [inline] __common_interrupt+0x134/0x220 arch/x86/kernel/irq.c:257 common_interrupt+0x4e/0xc0 arch/x86/kernel/irq.c:247 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:636 -> #2 (&tty->write_wait){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 __wake_up_common_lock kernel/sched/wait.c:137 [inline] __wake_up+0x101/0x1d0 kernel/sched/wait.c:160 tty_port_default_wakeup+0xa6/0xf0 drivers/tty/tty_port.c:69 serial8250_tx_chars+0x6b7/0x8b0 drivers/tty/serial/8250/8250_port.c:1842 serial8250_handle_irq+0x549/0x700 drivers/tty/serial/8250/8250_port.c:1949 serial8250_default_handle_irq+0xcc/0x1e0 drivers/tty/serial/8250/8250_port.c:1969 serial8250_interrupt+0xa5/0x1e0 drivers/tty/serial/8250/8250_core.c:127 __handle_irq_event_percpu+0x286/0xa20 kernel/irq/handle.c:158 handle_irq_event_percpu kernel/irq/handle.c:193 [inline] handle_irq_event+0x89/0x1f0 kernel/irq/handle.c:210 handle_edge_irq+0x249/0xbf0 kernel/irq/chip.c:831 generic_handle_irq_desc include/linux/irqdesc.h:161 [inline] handle_irq arch/x86/kernel/irq.c:238 [inline] __common_interrupt+0x134/0x220 arch/x86/kernel/irq.c:257 common_interrupt+0xa3/0xc0 arch/x86/kernel/irq.c:247 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:636 native_safe_halt arch/x86/include/asm/irqflags.h:48 [inline] arch_safe_halt arch/x86/include/asm/irqflags.h:86 [inline] acpi_safe_halt+0x20/0x30 drivers/acpi/processor_idle.c:112 acpi_idle_enter+0xe4/0x140 drivers/acpi/processor_idle.c:707 cpuidle_enter_state+0x10e/0x470 drivers/cpuidle/cpuidle.c:267 cpuidle_enter+0x5d/0x90 drivers/cpuidle/cpuidle.c:388 call_cpuidle kernel/sched/idle.c:134 [inline] cpuidle_idle_call kernel/sched/idle.c:215 [inline] do_idle+0x374/0x5c0 kernel/sched/idle.c:282 cpu_startup_entry+0x41/0x60 kernel/sched/idle.c:380 rest_init+0x2e0/0x300 init/main.c:726 arch_call_rest_init+0xe/0x10 init/main.c:823 start_kernel+0x46e/0x4f0 init/main.c:1068 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:556 x86_64_start_kernel+0x99/0xa0 arch/x86/kernel/head64.c:537 secondary_startup_64_no_verify+0x167/0x16b -> #1 (&port_lock_key){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162 uart_port_lock_irqsave include/linux/serial_core.h:616 [inline] serial8250_console_write+0x1a8/0x1820 drivers/tty/serial/8250/8250_port.c:3410 console_emit_next_record kernel/printk/printk.c:2894 [inline] console_flush_all+0x7ff/0xec0 kernel/printk/printk.c:2960 console_unlock+0x13b/0x4d0 kernel/printk/printk.c:3029 vprintk_emit+0x508/0x720 kernel/printk/printk.c:2304 _printk+0xd5/0x120 kernel/printk/printk.c:2329 register_console+0x705/0xcc0 kernel/printk/printk.c:3535 univ8250_console_init+0x45/0x50 drivers/tty/serial/8250/8250_core.c:717 console_init+0x193/0x670 kernel/printk/printk.c:3681 start_kernel+0x2d2/0x4f0 init/main.c:1004 x86_64_start_reservations+0x2a/0x30 arch/x86/kernel/head64.c:556 x86_64_start_kernel+0x99/0xa0 arch/x86/kernel/head64.c:537 secondary_startup_64_no_verify+0x167/0x16b -> #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+0x39ff/0x7f70 kernel/locking/lockdep.c:5136 lock_acquire+0x1e3/0x520 kernel/locking/lockdep.c:5753 console_lock_spinning_enable kernel/printk/printk.c:1855 [inline] console_emit_next_record kernel/printk/printk.c:2888 [inline] console_flush_all+0x7b2/0xec0 kernel/printk/printk.c:2960 console_unlock+0x13b/0x4d0 kernel/printk/printk.c:3029 vprintk_emit+0x508/0x720 kernel/printk/printk.c:2304 _printk+0xd5/0x120 kernel/printk/printk.c:2329 pick_eevdf+0x660/0x690 kernel/sched/fair.c:963 pick_next_entity kernel/sched/fair.c:5247 [inline] pick_next_task_fair+0x122/0xdc0 kernel/sched/fair.c:8205 __pick_next_task kernel/sched/core.c:5986 [inline] pick_next_task kernel/sched/core.c:6061 [inline] __schedule+0x7c7/0x4b00 kernel/sched/core.c:6640 __schedule_loop kernel/sched/core.c:6753 [inline] schedule+0x149/0x260 kernel/sched/core.c:6768 schedule_hrtimeout_range_clock+0x2a8/0x480 kernel/time/hrtimer.c:2317 ep_poll fs/eventpoll.c:1921 [inline] do_epoll_wait+0x1ba9/0x1e00 fs/eventpoll.c:2318 __do_sys_epoll_wait fs/eventpoll.c:2330 [inline] __se_sys_epoll_wait fs/eventpoll.c:2325 [inline] __x64_sys_epoll_wait+0x257/0x2a0 fs/eventpoll.c:2325 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x63/0xcd 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 *** 3 locks held by udevd/4500: #0: ffff8880b993c318 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:558 #1: ffffffff8d407ee0 (console_lock){+.+.}-{0:0}, at: _printk+0xd5/0x120 kernel/printk/printk.c:2329 #2: ffffffff8d407b10 (console_srcu){....}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:303 [inline] #2: ffffffff8d407b10 (console_srcu){....}-{0:0}, at: srcu_read_lock_nmisafe include/linux/srcu.h:232 [inline] #2: ffffffff8d407b10 (console_srcu){....}-{0:0}, at: console_srcu_read_lock kernel/printk/printk.c:286 [inline] #2: ffffffff8d407b10 (console_srcu){....}-{0:0}, at: console_flush_all+0x154/0xec0 kernel/printk/printk.c:2952 stack backtrace: CPU: 1 PID: 4500 Comm: udevd Not tainted 6.6.0-rc4-next-20231005-syzkaller-09984-g7d730f1bf6f3 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106 check_noncircular+0x375/0x4a0 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+0x39ff/0x7f70 kernel/locking/lockdep.c:5136 lock_acquire+0x1e3/0x520 kernel/locking/lockdep.c:5753 console_lock_spinning_enable kernel/printk/printk.c:1855 [inline] console_emit_next_record kernel/printk/printk.c:2888 [inline] console_flush_all+0x7b2/0xec0 kernel/printk/printk.c:2960 console_unlock+0x13b/0x4d0 kernel/printk/printk.c:3029 vprintk_emit+0x508/0x720 kernel/printk/printk.c:2304 _printk+0xd5/0x120 kernel/printk/printk.c:2329 pick_eevdf+0x660/0x690 kernel/sched/fair.c:963 pick_next_entity kernel/sched/fair.c:5247 [inline] pick_next_task_fair+0x122/0xdc0 kernel/sched/fair.c:8205 __pick_next_task kernel/sched/core.c:5986 [inline] pick_next_task kernel/sched/core.c:6061 [inline] __schedule+0x7c7/0x4b00 kernel/sched/core.c:6640 __schedule_loop kernel/sched/core.c:6753 [inline] schedule+0x149/0x260 kernel/sched/core.c:6768 schedule_hrtimeout_range_clock+0x2a8/0x480 kernel/time/hrtimer.c:2317 ep_poll fs/eventpoll.c:1921 [inline] do_epoll_wait+0x1ba9/0x1e00 fs/eventpoll.c:2318 __do_sys_epoll_wait fs/eventpoll.c:2330 [inline] __se_sys_epoll_wait fs/eventpoll.c:2325 [inline] __x64_sys_epoll_wait+0x257/0x2a0 fs/eventpoll.c:2325 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f1403523457 Code: 73 01 c3 48 8b 0d d1 d9 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 41 89 ca 64 8b 04 25 18 00 00 00 85 c0 75 20 b8 e8 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 76 48 8b 15 a2 d9 0c 00 f7 d8 64 89 02 48 83 RSP: 002b:00007ffee2935438 EFLAGS: 00000246 ORIG_RAX: 00000000000000e8 RAX: ffffffffffffffda RBX: 00007ffee2935538 RCX: 00007f1403523457 RDX: 0000000000000008 RSI: 00007ffee2935538 RDI: 000000000000000b RBP: 0000000000000000 R08: 00000000ffffffff R09: 0000000000000000 R10: 0000000000000bb8 R11: 0000000000000246 R12: 0000000000000bb8 R13: 000055717ac6c260 R14: 0000000000000000 R15: 0000000000000000 EEVDF scheduling fail, picking leftmost