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Message-Id: <20250213-atomic_sleep_mctrl_serial_gpio-v1-1-201ee6a148ad@bootlin.com>
Date: Thu, 13 Feb 2025 09:25:04 +0100
From: Alexis Lothoré <alexis.lothore@...tlin.com>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Jiri Slaby <jirislaby@...nel.org>,
Richard Genoud <richard.genoud@...tlin.com>,
Nicolas Ferre <nicolas.ferre@...rochip.com>,
Alexandre Belloni <alexandre.belloni@...tlin.com>,
Claudiu Beznea <claudiu.beznea@...on.dev>, Shawn Guo <shawnguo@...nel.org>,
Sascha Hauer <s.hauer@...gutronix.de>,
Pengutronix Kernel Team <kernel@...gutronix.de>,
Fabio Estevam <festevam@...il.com>,
Maxime Coquelin <mcoquelin.stm32@...il.com>,
Alexandre Torgue <alexandre.torgue@...s.st.com>
Cc: Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
linux-kernel@...r.kernel.org, linux-serial@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, imx@...ts.linux.dev,
linux-stm32@...md-mailman.stormreply.com,
Alexis Lothoré <alexis.lothore@...tlin.com>
Subject: [PATCH] serial: mctrl_gpio: add parameter to skip sync
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@...nel.org>
Signed-off-by: Alexis Lothoré <alexis.lothore@...tlin.com>
---
This series follows a report made here:
https://lore.kernel.org/linux-serial/3d227ebe-1ee6-4d57-b1ec-78be59af7244@bootlin.com/
---
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
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