The following splat has been observed on a SAMA5D27 platform using atmel_serial: BUG: sleeping function called from invalid context at kernel/irq/manage.c:738 in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 27, name: kworker/u5:0 preempt_count: 1, expected: 0 INFO: lockdep is turned off. irq event stamp: 0 hardirqs last enabled at (0): [<00000000>] 0x0 hardirqs last disabled at (0): [<c01588f0>] copy_process+0x1c4c/0x7bec softirqs last enabled at (0): [<c0158944>] copy_process+0x1ca0/0x7bec softirqs last disabled at (0): [<00000000>] 0x0 CPU: 0 UID: 0 PID: 27 Comm: kworker/u5:0 Not tainted 6.13.0-rc7+ #74 Hardware name: Atmel SAMA5 Workqueue: hci0 hci_power_on [bluetooth] Call trace: unwind_backtrace from show_stack+0x18/0x1c show_stack from dump_stack_lvl+0x44/0x70 dump_stack_lvl from __might_resched+0x38c/0x598 __might_resched from disable_irq+0x1c/0x48 disable_irq from mctrl_gpio_disable_ms+0x74/0xc0 mctrl_gpio_disable_ms from atmel_disable_ms.part.0+0x80/0x1f4 atmel_disable_ms.part.0 from atmel_set_termios+0x764/0x11e8 atmel_set_termios from uart_change_line_settings+0x15c/0x994 uart_change_line_settings from uart_set_termios+0x2b0/0x668 uart_set_termios from tty_set_termios+0x600/0x8ec tty_set_termios from ttyport_set_flow_control+0x188/0x1e0 ttyport_set_flow_control from wilc_setup+0xd0/0x524 [hci_wilc] wilc_setup [hci_wilc] from hci_dev_open_sync+0x330/0x203c [bluetooth] hci_dev_open_sync [bluetooth] from hci_dev_do_open+0x40/0xb0 [bluetooth] hci_dev_do_open [bluetooth] from hci_power_on+0x12c/0x664 [bluetooth] hci_power_on [bluetooth] from process_one_work+0x998/0x1a38 process_one_work from worker_thread+0x6e0/0xfb4 worker_thread from kthread+0x3d4/0x484 kthread from ret_from_fork+0x14/0x28 This warning is emitted when trying to toggle, at the highest level, some flow control (with serdev_device_set_flow_control) in a device driver. At the lowest level, the atmel_serial driver is using serial_mctrl_gpio lib to enable/disable the corresponding IRQs accordingly. The warning emitted by CONFIG_DEBUG_ATOMIC_SLEEP is due to disable_irq (called in mctrl_gpio_disable_ms) being possibly called in some atomic context (some tty drivers perform modem lines configuration in regions protected by port lock). Add a flag to mctrl_gpio_disable_ms to allow controlling whether the function should block, depending the context in which it is called. Update mctrl_gpio_disable_ms calls with the relevant flag value, depending on whether the call is protected by some port lock. Suggested-by: Jiri Slaby <jirislaby@xxxxxxxxxx> Signed-off-by: Alexis Lothoré <alexis.lothore@xxxxxxxxxxx> --- This series follows a report made here: https://lore.kernel.org/linux-serial/3d227ebe-1ee6-4d57-b1ec-78be59af7244@xxxxxxxxxxx/ --- drivers/tty/serial/8250/8250_port.c | 2 +- drivers/tty/serial/atmel_serial.c | 2 +- drivers/tty/serial/imx.c | 2 +- drivers/tty/serial/serial_mctrl_gpio.c | 9 +++++++-- drivers/tty/serial/serial_mctrl_gpio.h | 4 ++-- drivers/tty/serial/sh-sci.c | 2 +- drivers/tty/serial/stm32-usart.c | 2 +- 7 files changed, 14 insertions(+), 9 deletions(-) diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c index d7976a21cca9ce50557ca5f13bb01448ced0728b..b234c6c1fe8b3dae4efc2091c8aecf1f1dddc9f8 100644 --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -1680,7 +1680,7 @@ static void serial8250_disable_ms(struct uart_port *port) if (up->bugs & UART_BUG_NOMSR) return; - mctrl_gpio_disable_ms(up->gpios); + mctrl_gpio_disable_ms(up->gpios, false); up->ier &= ~UART_IER_MSI; serial_port_out(port, UART_IER, up->ier); diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c index f44f9d20a97440c9aea41e9ebe34c34d4dfa0a1c..eac0c266bd2fc13b0563c82b29f13f46df718625 100644 --- a/drivers/tty/serial/atmel_serial.c +++ b/drivers/tty/serial/atmel_serial.c @@ -700,7 +700,7 @@ static void atmel_disable_ms(struct uart_port *port) atmel_port->ms_irq_enabled = false; - mctrl_gpio_disable_ms(atmel_port->gpios); + mctrl_gpio_disable_ms(atmel_port->gpios, false); if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_CTS)) idr |= ATMEL_US_CTSIC; diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index 9c59ec128bb4fc0ff54cb9a1a66eabbc9e391a9a..af894a176a2fabea5374a35be5a63f453be5da96 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -1608,7 +1608,7 @@ static void imx_uart_shutdown(struct uart_port *port) imx_uart_dma_exit(sport); } - mctrl_gpio_disable_ms(sport->gpios); + mctrl_gpio_disable_ms(sport->gpios, true); uart_port_lock_irqsave(&sport->port, &flags); ucr2 = imx_uart_readl(sport, UCR2); diff --git a/drivers/tty/serial/serial_mctrl_gpio.c b/drivers/tty/serial/serial_mctrl_gpio.c index 8855688a5b6c09f073349bd144586f54331d891f..caef2be955eef95cc2efd508bc9ada2c948e3bf4 100644 --- a/drivers/tty/serial/serial_mctrl_gpio.c +++ b/drivers/tty/serial/serial_mctrl_gpio.c @@ -325,8 +325,10 @@ EXPORT_SYMBOL_GPL(mctrl_gpio_enable_ms); /** * mctrl_gpio_disable_ms - disable irqs and handling of changes to the ms lines * @gpios: gpios to disable + * @sync: true if function should block until any pending IRQ handler has + * executed */ -void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios) +void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios, bool sync) { enum mctrl_gpio_idx i; @@ -342,7 +344,10 @@ void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios) if (!gpios->irq[i]) continue; - disable_irq(gpios->irq[i]); + if (sync) + disable_irq(gpios->irq[i]); + else + disable_irq_nosync(gpios->irq[i]); } } EXPORT_SYMBOL_GPL(mctrl_gpio_disable_ms); diff --git a/drivers/tty/serial/serial_mctrl_gpio.h b/drivers/tty/serial/serial_mctrl_gpio.h index fc76910fb105a3d560e824baa43e9515576e895a..20f68dc3d63711214e1e65d22b8334b093dfc6fa 100644 --- a/drivers/tty/serial/serial_mctrl_gpio.h +++ b/drivers/tty/serial/serial_mctrl_gpio.h @@ -89,7 +89,7 @@ void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios); /* * Disable gpio interrupts to report status line changes. */ -void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios); +void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios, bool sync); /* * Enable gpio wakeup interrupts to enable wake up source. @@ -148,7 +148,7 @@ static inline void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios) { } -static inline void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios) +static inline void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios, bool sync) { } diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index b1ea48f38248eb42d98353daa289bbe67191d201..5d6d6d9af2eece94bdecb47933e1448dbb921114 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -2298,7 +2298,7 @@ static void sci_shutdown(struct uart_port *port) dev_dbg(port->dev, "%s(%d)\n", __func__, port->line); s->autorts = false; - mctrl_gpio_disable_ms(to_sci_port(port)->gpios); + mctrl_gpio_disable_ms(to_sci_port(port)->gpios, true); uart_port_lock_irqsave(port, &flags); sci_stop_rx(port); diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c index 1ec5d8c3aef8ddbca615a149c2fe81c90c83a22b..354894d4b468a51690568e83310b8400764e56a6 100644 --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -944,7 +944,7 @@ static void stm32_usart_enable_ms(struct uart_port *port) static void stm32_usart_disable_ms(struct uart_port *port) { - mctrl_gpio_disable_ms(to_stm32_port(port)->gpios); + mctrl_gpio_disable_ms(to_stm32_port(port)->gpios, true); } /* Transmit stop */ --- base-commit: 2014c95afecee3e76ca4a56956a936e23283f05b change-id: 20250213-atomic_sleep_mctrl_serial_gpio-885f6feb585b Best regards, -- Alexis Lothoré, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
