forked from TencentOS/TencentOS-kernel
commit 205d300aea75623e1ae4aa43e0d265ab9cf195fd upstream. We have a number of "uart.port->desc.lock vs desc.lock->uart.port" lockdep reports coming from 8250 driver; this causes a bit of trouble to people, so let's fix it. The problem is reverse lock order in two different call paths: chain #1: serial8250_do_startup() spin_lock_irqsave(&port->lock); disable_irq_nosync(port->irq); raw_spin_lock_irqsave(&desc->lock) chain #2: __report_bad_irq() raw_spin_lock_irqsave(&desc->lock) for_each_action_of_desc() printk() spin_lock_irqsave(&port->lock); Fix this by changing the order of locks in serial8250_do_startup(): do disable_irq_nosync() first, which grabs desc->lock, and grab uart->port after that, so that chain #1 and chain #2 have same lock order. Full lockdep splat: ====================================================== WARNING: possible circular locking dependency detected 5.4.39 #55 Not tainted ====================================================== swapper/0/0 is trying to acquire lock: ffffffffab65b6c0 (console_owner){-...}, at: console_lock_spinning_enable+0x31/0x57 but task is already holding lock: ffff88810a8e34c0 (&irq_desc_lock_class){-.-.}, at: __report_bad_irq+0x5b/0xba which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&irq_desc_lock_class){-.-.}: _raw_spin_lock_irqsave+0x61/0x8d __irq_get_desc_lock+0x65/0x89 __disable_irq_nosync+0x3b/0x93 serial8250_do_startup+0x451/0x75c uart_startup+0x1b4/0x2ff uart_port_activate+0x73/0xa0 tty_port_open+0xae/0x10a uart_open+0x1b/0x26 tty_open+0x24d/0x3a0 chrdev_open+0xd5/0x1cc do_dentry_open+0x299/0x3c8 path_openat+0x434/0x1100 do_filp_open+0x9b/0x10a do_sys_open+0x15f/0x3d7 kernel_init_freeable+0x157/0x1dd kernel_init+0xe/0x105 ret_from_fork+0x27/0x50 -> #1 (&port_lock_key){-.-.}: _raw_spin_lock_irqsave+0x61/0x8d serial8250_console_write+0xa7/0x2a0 console_unlock+0x3b7/0x528 vprintk_emit+0x111/0x17f printk+0x59/0x73 register_console+0x336/0x3a4 uart_add_one_port+0x51b/0x5be serial8250_register_8250_port+0x454/0x55e dw8250_probe+0x4dc/0x5b9 platform_drv_probe+0x67/0x8b really_probe+0x14a/0x422 driver_probe_device+0x66/0x130 device_driver_attach+0x42/0x5b __driver_attach+0xca/0x139 bus_for_each_dev+0x97/0xc9 bus_add_driver+0x12b/0x228 driver_register+0x64/0xed do_one_initcall+0x20c/0x4a6 do_initcall_level+0xb5/0xc5 do_basic_setup+0x4c/0x58 kernel_init_freeable+0x13f/0x1dd kernel_init+0xe/0x105 ret_from_fork+0x27/0x50 -> #0 (console_owner){-...}: __lock_acquire+0x118d/0x2714 lock_acquire+0x203/0x258 console_lock_spinning_enable+0x51/0x57 console_unlock+0x25d/0x528 vprintk_emit+0x111/0x17f printk+0x59/0x73 __report_bad_irq+0xa3/0xba note_interrupt+0x19a/0x1d6 handle_irq_event_percpu+0x57/0x79 handle_irq_event+0x36/0x55 handle_fasteoi_irq+0xc2/0x18a do_IRQ+0xb3/0x157 ret_from_intr+0x0/0x1d cpuidle_enter_state+0x12f/0x1fd cpuidle_enter+0x2e/0x3d do_idle+0x1ce/0x2ce cpu_startup_entry+0x1d/0x1f start_kernel+0x406/0x46a secondary_startup_64+0xa4/0xb0 other info that might help us debug this: Chain exists of: console_owner --> &port_lock_key --> &irq_desc_lock_class Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&irq_desc_lock_class); lock(&port_lock_key); lock(&irq_desc_lock_class); lock(console_owner); *** DEADLOCK *** 2 locks held by swapper/0/0: #0: ffff88810a8e34c0 (&irq_desc_lock_class){-.-.}, at: __report_bad_irq+0x5b/0xba #1: ffffffffab65b5c0 (console_lock){+.+.}, at: console_trylock_spinning+0x20/0x181 stack backtrace: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.4.39 #55 Hardware name: XXXXXX Call Trace: <IRQ> dump_stack+0xbf/0x133 ? print_circular_bug+0xd6/0xe9 check_noncircular+0x1b9/0x1c3 __lock_acquire+0x118d/0x2714 lock_acquire+0x203/0x258 ? console_lock_spinning_enable+0x31/0x57 console_lock_spinning_enable+0x51/0x57 ? console_lock_spinning_enable+0x31/0x57 console_unlock+0x25d/0x528 ? console_trylock+0x18/0x4e vprintk_emit+0x111/0x17f ? lock_acquire+0x203/0x258 printk+0x59/0x73 __report_bad_irq+0xa3/0xba note_interrupt+0x19a/0x1d6 handle_irq_event_percpu+0x57/0x79 handle_irq_event+0x36/0x55 handle_fasteoi_irq+0xc2/0x18a do_IRQ+0xb3/0x157 common_interrupt+0xf/0xf </IRQ> Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Fixes: 768aec0b5bcc ("serial: 8250: fix shared interrupts issues with SMP and RT kernels") Reported-by: Guenter Roeck <linux@roeck-us.net> Reported-by: Raul Rangel <rrangel@google.com> BugLink: https://bugs.chromium.org/p/chromium/issues/detail?id=1114800 Link: https://lore.kernel.org/lkml/CAHQZ30BnfX+gxjPm1DUd5psOTqbyDh4EJE=2=VAMW_VDafctkA@mail.gmail.com/T/#u Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Tested-by: Guenter Roeck <linux@roeck-us.net> Cc: stable <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20200817022646.1484638-1-sergey.senozhatsky@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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| .. | ||
| 8250 | ||
| cpm_uart | ||
| jsm | ||
| 21285.c | ||
| Kconfig | ||
| Makefile | ||
| altera_jtaguart.c | ||
| altera_uart.c | ||
| amba-pl010.c | ||
| amba-pl011.c | ||
| amba-pl011.h | ||
| apbuart.c | ||
| apbuart.h | ||
| ar933x_uart.c | ||
| arc_uart.c | ||
| atmel_serial.c | ||
| atmel_serial.h | ||
| bcm63xx_uart.c | ||
| clps711x.c | ||
| digicolor-usart.c | ||
| dz.c | ||
| dz.h | ||
| earlycon-arm-semihost.c | ||
| earlycon-riscv-sbi.c | ||
| earlycon.c | ||
| efm32-uart.c | ||
| fsl_linflexuart.c | ||
| fsl_lpuart.c | ||
| icom.c | ||
| icom.h | ||
| ifx6x60.c | ||
| ifx6x60.h | ||
| imx.c | ||
| ip22zilog.c | ||
| ip22zilog.h | ||
| kgdb_nmi.c | ||
| kgdboc.c | ||
| lantiq.c | ||
| lpc32xx_hs.c | ||
| max310x.c | ||
| max3100.c | ||
| mcf.c | ||
| men_z135_uart.c | ||
| meson_uart.c | ||
| milbeaut_usio.c | ||
| mpc52xx_uart.c | ||
| mps2-uart.c | ||
| msm_serial.c | ||
| mux.c | ||
| mvebu-uart.c | ||
| mxs-auart.c | ||
| omap-serial.c | ||
| owl-uart.c | ||
| pch_uart.c | ||
| pic32_uart.c | ||
| pic32_uart.h | ||
| pmac_zilog.c | ||
| pmac_zilog.h | ||
| pnx8xxx_uart.c | ||
| pxa.c | ||
| qcom_geni_serial.c | ||
| rda-uart.c | ||
| rp2.c | ||
| sa1100.c | ||
| samsung.c | ||
| samsung.h | ||
| sb1250-duart.c | ||
| sc16is7xx.c | ||
| sccnxp.c | ||
| serial-tegra.c | ||
| serial_core.c | ||
| serial_mctrl_gpio.c | ||
| serial_mctrl_gpio.h | ||
| serial_txx9.c | ||
| sh-sci.c | ||
| sh-sci.h | ||
| sifive.c | ||
| sirfsoc_uart.c | ||
| sirfsoc_uart.h | ||
| sprd_serial.c | ||
| st-asc.c | ||
| stm32-usart.c | ||
| stm32-usart.h | ||
| suncore.c | ||
| sunhv.c | ||
| sunsab.c | ||
| sunsab.h | ||
| sunsu.c | ||
| sunzilog.c | ||
| sunzilog.h | ||
| tegra-tcu.c | ||
| timbuart.c | ||
| timbuart.h | ||
| uartlite.c | ||
| ucc_uart.c | ||
| vr41xx_siu.c | ||
| vt8500_serial.c | ||
| xilinx_uartps.c | ||
| zs.c | ||
| zs.h | ||