======================================================== WARNING: possible irq lock inversion dependency detected 6.5.0-rc4-syzkaller #0 Not tainted -------------------------------------------------------- kworker/u4:6/1075 just changed the state of lock: ffffffff8d9461f8 (disc_data_lock){.?..}-{2:2}, at: ap_get+0x18/0xf0 drivers/net/ppp/ppp_async.c:136 but this lock was taken by another, HARDIRQ-safe lock in the past: (&port_lock_key){-.-.}-{2:2} and interrupts could create inverse lock ordering between them. other info that might help us debug this: Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(disc_data_lock); local_irq_disable(); lock(&port_lock_key); lock(disc_data_lock); lock(&port_lock_key); *** DEADLOCK *** 4 locks held by kworker/u4:6/1075: #0: ffff888012879138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:20 [inline] #0: ffff888012879138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: raw_atomic64_set include/linux/atomic/atomic-arch-fallback.h:2608 [inline] #0: ffff888012879138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: raw_atomic_long_set include/linux/atomic/atomic-long.h:79 [inline] #0: ffff888012879138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:3196 [inline] #0: ffff888012879138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:675 [inline] #0: ffff888012879138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:702 [inline] #0: ffff888012879138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x96a/0x16f0 kernel/workqueue.c:2567 #1: ffffc900055dfd80 ((work_completion)(&buf->work)){+.+.}-{0:0}, at: process_one_work+0x99e/0x16f0 kernel/workqueue.c:2571 #2: ffff8880132420b8 (&buf->lock){+.+.}-{3:3}, at: flush_to_ldisc+0x30/0x7c0 drivers/tty/tty_buffer.c:537 #3: ffff888033f4c098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref+0x1c/0x80 drivers/tty/tty_ldisc.c:263 the shortest dependencies between 2nd lock and 1st lock: -> (&port_lock_key){-.-.}-{2:2} { IN-HARDIRQ-W at: lock_acquire kernel/locking/lockdep.c:5761 [inline] lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5726 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x50 kernel/locking/spinlock.c:162 serial8250_handle_irq+0x91/0xbe0 drivers/tty/serial/8250/8250_port.c:1917 serial8250_default_handle_irq+0x94/0x210 drivers/tty/serial/8250/8250_port.c:1963 serial8250_interrupt+0xfc/0x200 drivers/tty/serial/8250/8250_core.c:127 __handle_irq_event_percpu+0x22a/0x740 kernel/irq/handle.c:158 handle_irq_event_percpu kernel/irq/handle.c:193 [inline] handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:210 handle_edge_irq+0x261/0xcf0 kernel/irq/chip.c:834 generic_handle_irq_desc include/linux/irqdesc.h:161 [inline] handle_irq arch/x86/kernel/irq.c:238 [inline] __common_interrupt+0x9f/0x220 arch/x86/kernel/irq.c:257 common_interrupt+0xa9/0xd0 arch/x86/kernel/irq.c:247 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:636 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline] _raw_spin_unlock_irqrestore+0x31/0x70 kernel/locking/spinlock.c:194 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] serial_port_runtime_resume+0x2ae/0x330 drivers/tty/serial/serial_port.c:41 __rpm_callback+0xc5/0x4c0 drivers/base/power/runtime.c:392 rpm_callback+0x1da/0x220 drivers/base/power/runtime.c:446 rpm_resume+0xdb9/0x1980 drivers/base/power/runtime.c:912 pm_runtime_work+0x12e/0x180 drivers/base/power/runtime.c:977 process_one_work+0xaa2/0x16f0 kernel/workqueue.c:2597 worker_thread+0x687/0x1110 kernel/workqueue.c:2748 kthread+0x33a/0x430 kernel/kthread.c:389 ret_from_fork+0x2c/0x70 arch/x86/kernel/process.c:145 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304 IN-SOFTIRQ-W at: lock_acquire kernel/locking/lockdep.c:5761 [inline] lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5726 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x50 kernel/locking/spinlock.c:162 serial8250_handle_irq+0x91/0xbe0 drivers/tty/serial/8250/8250_port.c:1917 serial8250_default_handle_irq+0x94/0x210 drivers/tty/serial/8250/8250_port.c:1963 serial8250_interrupt+0xfc/0x200 drivers/tty/serial/8250/8250_core.c:127 __handle_irq_event_percpu+0x22a/0x740 kernel/irq/handle.c:158 handle_irq_event_percpu kernel/irq/handle.c:193 [inline] handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:210 handle_edge_irq+0x261/0xcf0 kernel/irq/chip.c:834 generic_handle_irq_desc include/linux/irqdesc.h:161 [inline] handle_irq arch/x86/kernel/irq.c:238 [inline] __common_interrupt+0x9f/0x220 arch/x86/kernel/irq.c:257 common_interrupt+0xa9/0xd0 arch/x86/kernel/irq.c:247 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:636 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline] _raw_spin_unlock_irqrestore+0x31/0x70 kernel/locking/spinlock.c:194 __debug_check_no_obj_freed lib/debugobjects.c:1042 [inline] debug_check_no_obj_freed+0x245/0x4c0 lib/debugobjects.c:1063 slab_free_hook mm/slub.c:1767 [inline] slab_free_freelist_hook+0x182/0x1e0 mm/slub.c:1818 slab_free mm/slub.c:3801 [inline] kmem_cache_free+0xf0/0x490 mm/slub.c:3823 rcu_do_batch kernel/rcu/tree.c:2135 [inline] rcu_core+0x7fb/0x1bb0 kernel/rcu/tree.c:2399 __do_softirq+0x218/0x965 kernel/softirq.c:553 invoke_softirq kernel/softirq.c:427 [inline] __irq_exit_rcu kernel/softirq.c:632 [inline] irq_exit_rcu+0xb7/0x120 kernel/softirq.c:644 sysvec_apic_timer_interrupt+0x47/0xc0 arch/x86/kernel/apic/apic.c:1109 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645 INITIAL USE at: lock_acquire kernel/locking/lockdep.c:5761 [inline] lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5726 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x3a/0x50 kernel/locking/spinlock.c:162 serial8250_do_set_termios+0x334/0x1240 drivers/tty/serial/8250/8250_port.c:2794 serial8250_set_termios+0x6b/0x80 drivers/tty/serial/8250/8250_port.c:2913 uart_set_options+0x30e/0x5e0 drivers/tty/serial/serial_core.c:2284 serial8250_console_setup+0x18a/0x430 drivers/tty/serial/8250/8250_port.c:3507 univ8250_console_setup+0x168/0x210 drivers/tty/serial/8250/8250_core.c:631 try_enable_preferred_console+0x24d/0x470 kernel/printk/printk.c:3228 register_console+0x331/0x10d0 kernel/printk/printk.c:3401 univ8250_console_init+0x35/0x50 drivers/tty/serial/8250/8250_core.c:716 console_init+0xba/0x5c0 kernel/printk/printk.c:3601 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+0x167/0x16b } ... key at: [] port_lock_key+0x0/0x40 ... acquired at: __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline] _raw_read_lock+0x5f/0x70 kernel/locking/spinlock.c:228 ap_get+0x18/0xf0 drivers/net/ppp/ppp_async.c:136 ppp_asynctty_wakeup+0x18/0xb0 drivers/net/ppp/ppp_async.c:360 tty_wakeup+0xe5/0x120 drivers/tty/tty_io.c:525 tty_port_default_wakeup+0x2a/0x40 drivers/tty/tty_port.c:71 serial8250_tx_chars+0x542/0xf60 drivers/tty/serial/8250/8250_port.c:1839 __start_tx drivers/tty/serial/8250/8250_port.c:1547 [inline] serial8250_start_tx+0x7a8/0x980 drivers/tty/serial/8250/8250_port.c:1656 serial_port_runtime_resume+0x29e/0x330 drivers/tty/serial/serial_port.c:40 __rpm_callback+0xc5/0x4c0 drivers/base/power/runtime.c:392 rpm_callback+0x1da/0x220 drivers/base/power/runtime.c:446 rpm_resume+0xdb9/0x1980 drivers/base/power/runtime.c:912 pm_runtime_work+0x12e/0x180 drivers/base/power/runtime.c:977 process_one_work+0xaa2/0x16f0 kernel/workqueue.c:2597 worker_thread+0x687/0x1110 kernel/workqueue.c:2748 kthread+0x33a/0x430 kernel/kthread.c:389 ret_from_fork+0x2c/0x70 arch/x86/kernel/process.c:145 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304 -> (disc_data_lock){.?..}-{2:2} { IN-HARDIRQ-R at: lock_acquire kernel/locking/lockdep.c:5761 [inline] lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5726 __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline] _raw_read_lock+0x3a/0x70 kernel/locking/spinlock.c:228 ap_get+0x18/0xf0 drivers/net/ppp/ppp_async.c:136 ppp_asynctty_wakeup+0x18/0xb0 drivers/net/ppp/ppp_async.c:360 tty_wakeup+0xe5/0x120 drivers/tty/tty_io.c:525 tty_port_default_wakeup+0x2a/0x40 drivers/tty/tty_port.c:71 serial8250_tx_chars+0x542/0xf60 drivers/tty/serial/8250/8250_port.c:1839 serial8250_handle_irq+0x5fb/0xbe0 drivers/tty/serial/8250/8250_port.c:1943 serial8250_default_handle_irq+0x94/0x210 drivers/tty/serial/8250/8250_port.c:1963 serial8250_interrupt+0xfc/0x200 drivers/tty/serial/8250/8250_core.c:127 __handle_irq_event_percpu+0x22a/0x740 kernel/irq/handle.c:158 handle_irq_event_percpu kernel/irq/handle.c:193 [inline] handle_irq_event+0xab/0x1e0 kernel/irq/handle.c:210 handle_edge_irq+0x261/0xcf0 kernel/irq/chip.c:834 generic_handle_irq_desc include/linux/irqdesc.h:161 [inline] handle_irq arch/x86/kernel/irq.c:238 [inline] __common_interrupt+0x9f/0x220 arch/x86/kernel/irq.c:257 common_interrupt+0xa9/0xd0 arch/x86/kernel/irq.c:247 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:636 preempt_count arch/x86/include/asm/preempt.h:27 [inline] check_kcov_mode kernel/kcov.c:173 [inline] __sanitizer_cov_trace_pc+0xb/0x70 kernel/kcov.c:207 PageSwapBacked include/linux/page-flags.h:493 [inline] mm_counter_file include/linux/mm.h:2552 [inline] mm_counter include/linux/mm.h:2561 [inline] zap_pte_range mm/memory.c:1451 [inline] zap_pmd_range mm/memory.c:1570 [inline] zap_pud_range mm/memory.c:1599 [inline] zap_p4d_range mm/memory.c:1620 [inline] unmap_page_range+0x114c/0x32e0 mm/memory.c:1641 unmap_single_vma+0x194/0x2b0 mm/memory.c:1687 unmap_vmas+0x267/0x3c0 mm/memory.c:1726 exit_mmap+0x1a7/0x960 mm/mmap.c:3203 __mmput+0x12a/0x4d0 kernel/fork.c:1348 mmput+0x62/0x70 kernel/fork.c:1370 exit_mm kernel/exit.c:567 [inline] do_exit+0x9b4/0x2a20 kernel/exit.c:861 do_group_exit+0xd4/0x2a0 kernel/exit.c:1024 get_signal+0x23ea/0x2770 kernel/signal.c:2881 arch_do_signal_or_restart+0x89/0x5f0 arch/x86/kernel/signal.c:308 exit_to_user_mode_loop kernel/entry/common.c:168 [inline] exit_to_user_mode_prepare+0x11f/0x240 kernel/entry/common.c:204 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline] syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:297 do_syscall_64+0x44/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd HARDIRQ-ON-R at: lock_acquire kernel/locking/lockdep.c:5761 [inline] lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5726 __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline] _raw_read_lock+0x5f/0x70 kernel/locking/spinlock.c:228 ap_get+0x18/0xf0 drivers/net/ppp/ppp_async.c:136 ppp_asynctty_receive+0x2f/0x1580 drivers/net/ppp/ppp_async.c:343 tty_ldisc_receive_buf+0x143/0x180 drivers/tty/tty_buffer.c:461 tty_port_default_receive_buf+0x6f/0xa0 drivers/tty/tty_port.c:39 receive_buf drivers/tty/tty_buffer.c:515 [inline] flush_to_ldisc+0x252/0x7c0 drivers/tty/tty_buffer.c:565 process_one_work+0xaa2/0x16f0 kernel/workqueue.c:2597 worker_thread+0x687/0x1110 kernel/workqueue.c:2748 kthread+0x33a/0x430 kernel/kthread.c:389 ret_from_fork+0x2c/0x70 arch/x86/kernel/process.c:145 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304 INITIAL USE at: lock_acquire kernel/locking/lockdep.c:5761 [inline] lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5726 __raw_write_lock_irq include/linux/rwlock_api_smp.h:195 [inline] _raw_write_lock_irq+0x36/0x50 kernel/locking/spinlock.c:326 ppp_asynctty_close+0x1c/0x1c0 drivers/net/ppp/ppp_async.c:219 tty_ldisc_close+0x111/0x190 drivers/tty/tty_ldisc.c:455 tty_ldisc_kill+0x94/0x150 drivers/tty/tty_ldisc.c:607 tty_ldisc_release+0x116/0x2a0 drivers/tty/tty_ldisc.c:775 tty_release_struct+0x23/0xe0 drivers/tty/tty_io.c:1698 tty_release+0xe23/0x1410 drivers/tty/tty_io.c:1869 __fput+0x3fd/0xac0 fs/file_table.c:384 task_work_run+0x14d/0x240 kernel/task_work.c:179 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop kernel/entry/common.c:171 [inline] exit_to_user_mode_prepare+0x210/0x240 kernel/entry/common.c:204 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline] syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:297 do_syscall_64+0x44/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd INITIAL READ USE at: lock_acquire kernel/locking/lockdep.c:5761 [inline] lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5726 __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline] _raw_read_lock+0x5f/0x70 kernel/locking/spinlock.c:228 ap_get+0x18/0xf0 drivers/net/ppp/ppp_async.c:136 ppp_asynctty_wakeup+0x18/0xb0 drivers/net/ppp/ppp_async.c:360 tty_wakeup+0xe5/0x120 drivers/tty/tty_io.c:525 tty_port_default_wakeup+0x2a/0x40 drivers/tty/tty_port.c:71 serial8250_tx_chars+0x542/0xf60 drivers/tty/serial/8250/8250_port.c:1839 __start_tx drivers/tty/serial/8250/8250_port.c:1547 [inline] serial8250_start_tx+0x7a8/0x980 drivers/tty/serial/8250/8250_port.c:1656 serial_port_runtime_resume+0x29e/0x330 drivers/tty/serial/serial_port.c:40 __rpm_callback+0xc5/0x4c0 drivers/base/power/runtime.c:392 rpm_callback+0x1da/0x220 drivers/base/power/runtime.c:446 rpm_resume+0xdb9/0x1980 drivers/base/power/runtime.c:912 pm_runtime_work+0x12e/0x180 drivers/base/power/runtime.c:977 process_one_work+0xaa2/0x16f0 kernel/workqueue.c:2597 worker_thread+0x687/0x1110 kernel/workqueue.c:2748 kthread+0x33a/0x430 kernel/kthread.c:389 ret_from_fork+0x2c/0x70 arch/x86/kernel/process.c:145 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304 } ... key at: [] disc_data_lock+0x18/0x60 ... acquired at: mark_usage kernel/locking/lockdep.c:4586 [inline] __lock_acquire+0x13a5/0x5de0 kernel/locking/lockdep.c:5098 lock_acquire kernel/locking/lockdep.c:5761 [inline] lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5726 __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline] _raw_read_lock+0x5f/0x70 kernel/locking/spinlock.c:228 ap_get+0x18/0xf0 drivers/net/ppp/ppp_async.c:136 ppp_asynctty_receive+0x2f/0x1580 drivers/net/ppp/ppp_async.c:343 tty_ldisc_receive_buf+0x143/0x180 drivers/tty/tty_buffer.c:461 tty_port_default_receive_buf+0x6f/0xa0 drivers/tty/tty_port.c:39 receive_buf drivers/tty/tty_buffer.c:515 [inline] flush_to_ldisc+0x252/0x7c0 drivers/tty/tty_buffer.c:565 process_one_work+0xaa2/0x16f0 kernel/workqueue.c:2597 worker_thread+0x687/0x1110 kernel/workqueue.c:2748 kthread+0x33a/0x430 kernel/kthread.c:389 ret_from_fork+0x2c/0x70 arch/x86/kernel/process.c:145 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304 stack backtrace: CPU: 0 PID: 1075 Comm: kworker/u4:6 Not tainted 6.5.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2023 Workqueue: events_unbound flush_to_ldisc Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106 print_irq_inversion_bug.part.0+0x3e1/0x590 kernel/locking/lockdep.c:4087 print_irq_inversion_bug kernel/locking/lockdep.c:4040 [inline] check_usage_forwards kernel/locking/lockdep.c:4118 [inline] mark_lock_irq kernel/locking/lockdep.c:4250 [inline] mark_lock+0x920/0x1950 kernel/locking/lockdep.c:4685 mark_usage kernel/locking/lockdep.c:4586 [inline] __lock_acquire+0x13a5/0x5de0 kernel/locking/lockdep.c:5098 lock_acquire kernel/locking/lockdep.c:5761 [inline] lock_acquire+0x1ae/0x510 kernel/locking/lockdep.c:5726 __raw_read_lock include/linux/rwlock_api_smp.h:150 [inline] _raw_read_lock+0x5f/0x70 kernel/locking/spinlock.c:228 ap_get+0x18/0xf0 drivers/net/ppp/ppp_async.c:136 ppp_asynctty_receive+0x2f/0x1580 drivers/net/ppp/ppp_async.c:343 tty_ldisc_receive_buf+0x143/0x180 drivers/tty/tty_buffer.c:461 tty_port_default_receive_buf+0x6f/0xa0 drivers/tty/tty_port.c:39 receive_buf drivers/tty/tty_buffer.c:515 [inline] flush_to_ldisc+0x252/0x7c0 drivers/tty/tty_buffer.c:565 process_one_work+0xaa2/0x16f0 kernel/workqueue.c:2597 worker_thread+0x687/0x1110 kernel/workqueue.c:2748 kthread+0x33a/0x430 kernel/kthread.c:389 ret_from_fork+0x2c/0x70 arch/x86/kernel/process.c:145 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304