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Message-Id: <20250505223922.2682012-306-sashal@kernel.org>
Date: Mon, 5 May 2025 18:36:22 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org,
stable@...r.kernel.org
Cc: Alexis Lothoré <alexis.lothore@...tlin.com>,
Jiri Slaby <jirislaby@...nel.org>,
Richard Genoud <richard.genoud@...tlin.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Sasha Levin <sashal@...nel.org>,
corbet@....net,
nicolas.ferre@...rochip.com,
alexandre.belloni@...tlin.com,
claudiu.beznea@...on.dev,
shawnguo@...nel.org,
mcoquelin.stm32@...il.com,
alexandre.torgue@...s.st.com,
john.ogness@...utronix.de,
pmladek@...e.com,
arnd@...db.de,
andriy.shevchenko@...ux.intel.com,
namcao@...utronix.de,
benjamin.larsson@...exis.eu,
schnelle@...ux.ibm.com,
esben@...nix.com,
stefan.eichenberger@...adex.com,
tglx@...utronix.de,
linux@...musvillemoes.dk,
marex@...x.de,
jeff.johnson@....qualcomm.com,
linux@...blig.org,
geert+renesas@...der.be,
wsa+renesas@...g-engineering.com,
prabhakar.mahadev-lad.rj@...renesas.com,
cheick.traore@...s.st.com,
ben.wolsieffer@...ring.com,
u.kleine-koenig@...libre.com,
linux-serial@...r.kernel.org,
linux-doc@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org,
imx@...ts.linux.dev,
linux-stm32@...md-mailman.stormreply.com
Subject: [PATCH AUTOSEL 6.12 306/486] serial: mctrl_gpio: split disable_ms into sync and no_sync APIs
From: Alexis Lothoré <alexis.lothore@...tlin.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@...nel.org>
Signed-off-by: Alexis Lothoré <alexis.lothore@...tlin.com>
Acked-by: Richard Genoud <richard.genoud@...tlin.com>
Link: https://lore.kernel.org/r/20250217-atomic_sleep_mctrl_serial_gpio-v3-1-59324b313eef@bootlin.com
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Signed-off-by: Sasha Levin <sashal@...nel.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 */
--
2.39.5
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