------------[ cut here ]------------ WARNING: CPU: 1 PID: 7393 at drivers/tty/serial/serial_core.c:625 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] WARNING: CPU: 1 PID: 7393 at drivers/tty/serial/serial_core.c:625 uart_port_unlock_irqrestore include/linux/serial_core.h:669 [inline] WARNING: CPU: 1 PID: 7393 at drivers/tty/serial/serial_core.c:625 uart_write+0x280/0x2ec drivers/tty/serial/serial_core.c:626 Modules linked in: CPU: 1 PID: 7393 Comm: syz-executor.3 Tainted: G W 6.10.0-rc3-syzkaller-gac2193b4b460 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024 pstate: 804000c5 (Nzcv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : uart_write+0x280/0x2ec include/linux/spinlock.h:406 lr : uart_write+0x278/0x2ec drivers/tty/serial/serial_core.c:625 sp : ffff80009ce377a0 ====================================================== WARNING: possible circular locking dependency detected 6.10.0-rc3-syzkaller-gac2193b4b460 #0 Tainted: G W ------------------------------------------------------ syz-executor.3/7393 is trying to acquire lock: ffff80008f36cea0 (console_owner){-.-.}-{0:0}, at: console_trylock_spinning+0x1cc/0x3d8 kernel/printk/printk.c:1977 but task is already holding lock: ffff800093dcec98 (&port_lock_key){-.-.}-{2:2}, at: uart_port_lock_irqsave include/linux/serial_core.h:618 [inline] ffff800093dcec98 (&port_lock_key){-.-.}-{2:2}, at: uart_write+0x114/0x2ec drivers/tty/serial/serial_core.c:624 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&port_lock_key){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x5c/0x7c kernel/locking/spinlock.c:162 uart_port_lock_irqsave include/linux/serial_core.h:618 [inline] pl011_console_write+0x148/0x724 drivers/tty/serial/amba-pl011.c:2316 console_emit_next_record kernel/printk/printk.c:2928 [inline] console_flush_all+0x570/0xafc kernel/printk/printk.c:2994 console_unlock+0xfc/0x3d4 kernel/printk/printk.c:3063 vprintk_emit+0x1e8/0x344 kernel/printk/printk.c:2345 vprintk_default+0xa0/0xe4 kernel/printk/printk.c:2360 vprintk+0x200/0x2d4 kernel/printk/printk_safe.c:45 _printk+0xdc/0x128 kernel/printk/printk.c:2370 register_console+0x700/0xa8c kernel/printk/printk.c:3596 uart_configure_port drivers/tty/serial/serial_core.c:2664 [inline] serial_core_add_one_port drivers/tty/serial/serial_core.c:3192 [inline] serial_core_register_port+0x1428/0x1bf4 drivers/tty/serial/serial_core.c:3429 serial_ctrl_register_port+0x28/0x38 drivers/tty/serial/serial_ctrl.c:41 uart_add_one_port+0x28/0x38 drivers/tty/serial/serial_port.c:136 pl011_register_port+0x1b4/0x44c drivers/tty/serial/amba-pl011.c:2744 sbsa_uart_probe+0x488/0x608 drivers/tty/serial/amba-pl011.c:2914 platform_probe+0x148/0x1c0 drivers/base/platform.c:1404 really_probe+0x38c/0x8fc drivers/base/dd.c:656 __driver_probe_device+0x194/0x374 drivers/base/dd.c:798 driver_probe_device+0x78/0x330 drivers/base/dd.c:828 __device_attach_driver+0x2a8/0x4f4 drivers/base/dd.c:956 bus_for_each_drv+0x228/0x2bc drivers/base/bus.c:457 __device_attach+0x2b4/0x434 drivers/base/dd.c:1028 device_initial_probe+0x24/0x34 drivers/base/dd.c:1077 bus_probe_device+0x178/0x240 drivers/base/bus.c:532 device_add+0x728/0xa6c drivers/base/core.c:3721 platform_device_add+0x3e8/0x6e8 drivers/base/platform.c:716 platform_device_register_full+0x4ec/0x604 drivers/base/platform.c:844 acpi_create_platform_device+0x5bc/0x744 drivers/acpi/acpi_platform.c:177 acpi_default_enumeration+0x6c/0xdc drivers/acpi/scan.c:2184 acpi_bus_attach+0x8b8/0xaa8 drivers/acpi/scan.c:2293 acpi_dev_for_one_check+0xa0/0xb4 drivers/acpi/bus.c:1143 device_for_each_child+0xec/0x174 drivers/base/core.c:4050 acpi_dev_for_each_child+0xc4/0x108 drivers/acpi/bus.c:1155 acpi_bus_attach+0x358/0xaa8 drivers/acpi/scan.c:2298 acpi_dev_for_one_check+0xa0/0xb4 drivers/acpi/bus.c:1143 device_for_each_child+0xec/0x174 drivers/base/core.c:4050 acpi_dev_for_each_child+0xc4/0x108 drivers/acpi/bus.c:1155 acpi_bus_attach+0x358/0xaa8 drivers/acpi/scan.c:2298 acpi_bus_scan+0x118/0x4f0 drivers/acpi/scan.c:2579 acpi_scan_init+0x214/0x6b0 drivers/acpi/scan.c:2714 acpi_init+0x190/0x254 drivers/acpi/bus.c:1460 do_one_initcall+0x24c/0x9c0 init/main.c:1267 do_initcall_level+0x154/0x214 init/main.c:1329 do_initcalls+0x58/0xac init/main.c:1345 do_basic_setup+0x8c/0xa0 init/main.c:1364 kernel_init_freeable+0x324/0x478 init/main.c:1578 kernel_init+0x24/0x2a0 init/main.c:1467 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860 -> #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:3869 [inline] __lock_acquire+0x3384/0x763c kernel/locking/lockdep.c:5137 lock_acquire+0x240/0x728 kernel/locking/lockdep.c:5754 console_trylock_spinning+0x1f8/0x3d8 kernel/printk/printk.c:1994 vprintk_emit+0x1cc/0x344 kernel/printk/printk.c:2344 vprintk_default+0xa0/0xe4 kernel/printk/printk.c:2360 vprintk+0x200/0x2d4 kernel/printk/printk_safe.c:45 _printk+0xdc/0x128 kernel/printk/printk.c:2370 __show_regs+0x4e4/0x650 arch/arm64/kernel/process.c:226 show_regs+0x20/0x44 arch/arm64/kernel/process.c:245 __warn+0x130/0x6b0 kernel/panic.c:691 __report_bug lib/bug.c:199 [inline] report_bug+0x298/0x5b0 lib/bug.c:219 bug_handler+0x50/0x1fc arch/arm64/kernel/traps.c:978 call_break_hook arch/arm64/kernel/debug-monitors.c:321 [inline] brk_handler+0x17c/0x2e0 arch/arm64/kernel/debug-monitors.c:328 do_debug_exception+0x1e4/0x398 arch/arm64/mm/fault.c:909 el1_dbg+0x64/0x80 arch/arm64/kernel/entry-common.c:472 el1h_64_sync_handler+0x40/0xac arch/arm64/kernel/entry-common.c:512 el1h_64_sync+0x64/0x68 arch/arm64/kernel/entry.S:593 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] uart_port_unlock_irqrestore include/linux/serial_core.h:669 [inline] uart_write+0x280/0x2ec drivers/tty/serial/serial_core.c:626 ppp_async_push+0x258/0x1608 drivers/net/ppp/ppp_async.c:666 ppp_async_send+0xb0/0x114 drivers/net/ppp/ppp_async.c:634 __ppp_channel_push+0xe0/0x1ac drivers/net/ppp/ppp_generic.c:2150 ppp_channel_push+0x17c/0x208 drivers/net/ppp/ppp_generic.c:2177 ppp_write+0x288/0x374 drivers/net/ppp/ppp_generic.c:525 do_loop_readv_writev fs/read_write.c:764 [inline] vfs_writev+0x6c8/0xb80 fs/read_write.c:973 do_pwritev fs/read_write.c:1072 [inline] __do_sys_pwritev fs/read_write.c:1119 [inline] __se_sys_pwritev fs/read_write.c:1114 [inline] __arm64_sys_pwritev+0x18c/0x29c fs/read_write.c:1114 __invoke_syscall arch/arm64/kernel/syscall.c:34 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:48 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:133 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:152 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&port_lock_key); lock(console_owner); lock(&port_lock_key); lock(console_owner); *** DEADLOCK *** 4 locks held by syz-executor.3/7393: #0: ffff0000dcf62a48 (&pch->upl){++..}-{2:2}, at: ppp_channel_push+0x38/0x208 drivers/net/ppp/ppp_generic.c:2171 #1: ffff0000dcf629e0 (&pch->downl){+...}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] #1: ffff0000dcf629e0 (&pch->downl){+...}-{2:2}, at: __ppp_channel_push+0x3c/0x1ac drivers/net/ppp/ppp_generic.c:2146 #2: ffff0000f51e4030 (&ap->xmit_lock){+...}-{2:2}, at: spin_lock_bh include/linux/spinlock.h:356 [inline] #2: ffff0000f51e4030 (&ap->xmit_lock){+...}-{2:2}, at: ppp_async_push+0x8c/0x1608 drivers/net/ppp/ppp_async.c:659 #3: ffff800093dcec98 (&port_lock_key){-.-.}-{2:2}, at: uart_port_lock_irqsave include/linux/serial_core.h:618 [inline] #3: ffff800093dcec98 (&port_lock_key){-.-.}-{2:2}, at: uart_write+0x114/0x2ec drivers/tty/serial/serial_core.c:624 stack backtrace: CPU: 1 PID: 7393 Comm: syz-executor.3 Tainted: G W 6.10.0-rc3-syzkaller-gac2193b4b460 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024 Call trace: dump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:317 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:324 __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xe4/0x150 lib/dump_stack.c:114 dump_stack+0x1c/0x28 lib/dump_stack.c:123 print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2060 check_noncircular+0x310/0x404 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:3869 [inline] __lock_acquire+0x3384/0x763c kernel/locking/lockdep.c:5137 lock_acquire+0x240/0x728 kernel/locking/lockdep.c:5754 console_trylock_spinning+0x1f8/0x3d8 kernel/printk/printk.c:1994 vprintk_emit+0x1cc/0x344 kernel/printk/printk.c:2344 vprintk_default+0xa0/0xe4 kernel/printk/printk.c:2360 vprintk+0x200/0x2d4 kernel/printk/printk_safe.c:45 _printk+0xdc/0x128 kernel/printk/printk.c:2370 __show_regs+0x4e4/0x650 arch/arm64/kernel/process.c:226 show_regs+0x20/0x44 arch/arm64/kernel/process.c:245 __warn+0x130/0x6b0 kernel/panic.c:691 __report_bug lib/bug.c:199 [inline] report_bug+0x298/0x5b0 lib/bug.c:219 bug_handler+0x50/0x1fc arch/arm64/kernel/traps.c:978 call_break_hook arch/arm64/kernel/debug-monitors.c:321 [inline] brk_handler+0x17c/0x2e0 arch/arm64/kernel/debug-monitors.c:328 do_debug_exception+0x1e4/0x398 arch/arm64/mm/fault.c:909 el1_dbg+0x64/0x80 arch/arm64/kernel/entry-common.c:472 el1h_64_sync_handler+0x40/0xac arch/arm64/kernel/entry-common.c:512 el1h_64_sync+0x64/0x68 arch/arm64/kernel/entry.S:593 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] uart_port_unlock_irqrestore include/linux/serial_core.h:669 [inline] uart_write+0x280/0x2ec drivers/tty/serial/serial_core.c:626 ppp_async_push+0x258/0x1608 drivers/net/ppp/ppp_async.c:666 ppp_async_send+0xb0/0x114 drivers/net/ppp/ppp_async.c:634 __ppp_channel_push+0xe0/0x1ac drivers/net/ppp/ppp_generic.c:2150 ppp_channel_push+0x17c/0x208 drivers/net/ppp/ppp_generic.c:2177 ppp_write+0x288/0x374 drivers/net/ppp/ppp_generic.c:525 do_loop_readv_writev fs/read_write.c:764 [inline] vfs_writev+0x6c8/0xb80 fs/read_write.c:973 do_pwritev fs/read_write.c:1072 [inline] __do_sys_pwritev fs/read_write.c:1119 [inline] __se_sys_pwritev fs/read_write.c:1114 [inline] __arm64_sys_pwritev+0x18c/0x29c fs/read_write.c:1114 __invoke_syscall arch/arm64/kernel/syscall.c:34 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:48 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:133 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:152 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598 x29: ffff80009ce377a0 x28: ffff0000f51e40e8 x27: ffff0000f51e40e0 x26: 0000000000000001 x25: dfff800000000000 x24: ffff0000c93e8f48 x23: 0000000000000000 x22: ffff800093dcec80 x21: ffff0000f51e4210 x20: 0000000000000ffa x19: ffff0000c93e8be8 x18: ffff80009ce37440 x17: 0000000000023386 x16: ffff800080350d3c x15: ffff7000139c6ed8 x14: 1ffff000139c6ed8 x13: 0000000000000004 x12: ffffffffffffffff x11: 0000000000040000 x10: 0000000000003819 x9 : ffff8000a2903000 x8 : 000000000000381a x7 : 0000000000000000 x6 : 0000000000000000 x5 : ffff800092d48680 x4 : 0000000000000008 x3 : ffff800080350e64 x2 : 0000000000000001 x1 : 0000000000000000 x0 : ffff800093dcec80 Call trace: spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] uart_port_unlock_irqrestore include/linux/serial_core.h:669 [inline] uart_write+0x280/0x2ec drivers/tty/serial/serial_core.c:626 ppp_async_push+0x258/0x1608 drivers/net/ppp/ppp_async.c:666 ppp_async_send+0xb0/0x114 drivers/net/ppp/ppp_async.c:634 __ppp_channel_push+0xe0/0x1ac drivers/net/ppp/ppp_generic.c:2150 ppp_channel_push+0x17c/0x208 drivers/net/ppp/ppp_generic.c:2177 ppp_write+0x288/0x374 drivers/net/ppp/ppp_generic.c:525 do_loop_readv_writev fs/read_write.c:764 [inline] vfs_writev+0x6c8/0xb80 fs/read_write.c:973 do_pwritev fs/read_write.c:1072 [inline] __do_sys_pwritev fs/read_write.c:1119 [inline] __se_sys_pwritev fs/read_write.c:1114 [inline] __arm64_sys_pwritev+0x18c/0x29c fs/read_write.c:1114 __invoke_syscall arch/arm64/kernel/syscall.c:34 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:48 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:133 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:152 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712 el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598 irq event stamp: 1589 hardirqs last enabled at (1588): [] __local_bh_enable_ip+0x224/0x44c kernel/softirq.c:387 hardirqs last disabled at (1589): [] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:108 [inline] hardirqs last disabled at (1589): [] _raw_spin_lock_irqsave+0x2c/0x7c kernel/locking/spinlock.c:162 softirqs last enabled at (1572): [] local_bh_enable+0x10/0x34 include/linux/bottom_half.h:32 softirqs last disabled at (1584): [] ppp_channel_push+0x38/0x208 drivers/net/ppp/ppp_generic.c:2171 ---[ end trace 0000000000000000 ]---