From: Alexis Lothoré alexis.lothore@bootlin.com
[ Upstream commit 1bd2aad57da95f7f2d2bb52f7ad15c0f4993a685 ]
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).
Split mctrl_gpio_disable_ms into two differents APIs, a non-blocking one and a blocking one. Replace mctrl_gpio_disable_ms calls with the relevant version depending on whether the call is protected by some port lock.
Suggested-by: Jiri Slaby jirislaby@kernel.org Signed-off-by: Alexis Lothoré alexis.lothore@bootlin.com Acked-by: Richard Genoud richard.genoud@bootlin.com Link: https://lore.kernel.org/r/20250217-atomic_sleep_mctrl_serial_gpio-v3-1-59324... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- Documentation/driver-api/serial/driver.rst | 2 +- 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 | 34 +++++++++++++++++----- drivers/tty/serial/serial_mctrl_gpio.h | 17 +++++++++-- drivers/tty/serial/sh-sci.c | 2 +- drivers/tty/serial/stm32-usart.c | 2 +- 8 files changed, 47 insertions(+), 16 deletions(-)
diff --git a/Documentation/driver-api/serial/driver.rst b/Documentation/driver-api/serial/driver.rst index 84b43061c11be..60434f2b02863 100644 --- a/Documentation/driver-api/serial/driver.rst +++ b/Documentation/driver-api/serial/driver.rst @@ -103,4 +103,4 @@ Some helpers are provided in order to set/get modem control lines via GPIO. .. kernel-doc:: drivers/tty/serial/serial_mctrl_gpio.c :identifiers: mctrl_gpio_init mctrl_gpio_free mctrl_gpio_to_gpiod mctrl_gpio_set mctrl_gpio_get mctrl_gpio_enable_ms - mctrl_gpio_disable_ms + mctrl_gpio_disable_ms_sync mctrl_gpio_disable_ms_no_sync diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c index c1376727642a7..0519679929652 100644 --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -1657,7 +1657,7 @@ 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_no_sync(up->gpios);
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 09b246c9e389e..8bd39586a49f7 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_no_sync(atmel_port->gpios);
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 90974d338f3c0..8e3b15534bc72 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -1596,7 +1596,7 @@ static void imx_uart_shutdown(struct uart_port *port) imx_uart_dma_exit(sport); }
- mctrl_gpio_disable_ms(sport->gpios); + mctrl_gpio_disable_ms_sync(sport->gpios);
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 8855688a5b6c0..ca55bcc0b6111 100644 --- a/drivers/tty/serial/serial_mctrl_gpio.c +++ b/drivers/tty/serial/serial_mctrl_gpio.c @@ -322,11 +322,7 @@ void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios) } 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 - */ -void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios) +static void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios, bool sync) { enum mctrl_gpio_idx i;
@@ -342,10 +338,34 @@ 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); + +/** + * mctrl_gpio_disable_ms_sync - disable irqs and handling of changes to the ms + * lines, and wait for any pending IRQ to be processed + * @gpios: gpios to disable + */ +void mctrl_gpio_disable_ms_sync(struct mctrl_gpios *gpios) +{ + mctrl_gpio_disable_ms(gpios, true); +} +EXPORT_SYMBOL_GPL(mctrl_gpio_disable_ms_sync); + +/** + * mctrl_gpio_disable_ms_no_sync - disable irqs and handling of changes to the + * ms lines, and return immediately + * @gpios: gpios to disable + */ +void mctrl_gpio_disable_ms_no_sync(struct mctrl_gpios *gpios) +{ + mctrl_gpio_disable_ms(gpios, false); +} +EXPORT_SYMBOL_GPL(mctrl_gpio_disable_ms_no_sync);
void mctrl_gpio_enable_irq_wake(struct mctrl_gpios *gpios) { diff --git a/drivers/tty/serial/serial_mctrl_gpio.h b/drivers/tty/serial/serial_mctrl_gpio.h index fc76910fb105a..79e97838ebe56 100644 --- a/drivers/tty/serial/serial_mctrl_gpio.h +++ b/drivers/tty/serial/serial_mctrl_gpio.h @@ -87,9 +87,16 @@ void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios); void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios);
/* - * Disable gpio interrupts to report status line changes. + * Disable gpio interrupts to report status line changes, and block until + * any corresponding IRQ is processed */ -void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios); +void mctrl_gpio_disable_ms_sync(struct mctrl_gpios *gpios); + +/* + * Disable gpio interrupts to report status line changes, and return + * immediately + */ +void mctrl_gpio_disable_ms_no_sync(struct mctrl_gpios *gpios);
/* * Enable gpio wakeup interrupts to enable wake up source. @@ -148,7 +155,11 @@ 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_sync(struct mctrl_gpios *gpios) +{ +} + +static inline void mctrl_gpio_disable_ms_no_sync(struct mctrl_gpios *gpios) { }
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index f43059e1b5c28..80efe3b0ed0c3 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -2297,7 +2297,7 @@ 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_sync(to_sci_port(port)->gpios);
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 9b9981352b1e1..e685cace5c854 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_sync(to_stm32_port(port)->gpios); }
/* Transmit stop */