<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/tty/serial, branch v6.9.3</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>serial: 8520_mtk: Set RTS on shutdown for Rx in-band wakeup</title>
<updated>2024-05-30T07:43:59+00:00</updated>
<author>
<name>Pin-yen Lin</name>
<email>treapking@chromium.org</email>
</author>
<published>2024-04-24T12:58:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1f97ccd2c32ad8f0322e4fe3a291a61e509b3e5e'/>
<id>1f97ccd2c32ad8f0322e4fe3a291a61e509b3e5e</id>
<content type='text'>
commit 4244f830a56058ee0670d80e7ac9fd7c982eb480 upstream.

When Rx in-band wakeup is enabled, set RTS to true in mtk8250_shutdown()
so the connected device can still send message and trigger IRQ when the
system is suspended.

Fixes: 18c9d4a3c249 ("serial: When UART is suspended, set RTS to false")
Cc: stable &lt;stable@kernel.org&gt;
Signed-off-by: Pin-yen Lin &lt;treapking@chromium.org&gt;
Link: https://lore.kernel.org/r/20240424130619.2924456-1-treapking@chromium.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 4244f830a56058ee0670d80e7ac9fd7c982eb480 upstream.

When Rx in-band wakeup is enabled, set RTS to true in mtk8250_shutdown()
so the connected device can still send message and trigger IRQ when the
system is suspended.

Fixes: 18c9d4a3c249 ("serial: When UART is suspended, set RTS to false")
Cc: stable &lt;stable@kernel.org&gt;
Signed-off-by: Pin-yen Lin &lt;treapking@chromium.org&gt;
Link: https://lore.kernel.org/r/20240424130619.2924456-1-treapking@chromium.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>serial: 8250_bcm7271: use default_mux_rate if possible</title>
<updated>2024-05-30T07:43:59+00:00</updated>
<author>
<name>Doug Berger</name>
<email>opendmb@gmail.com</email>
</author>
<published>2024-04-24T22:25:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f98bc68a3244beacf8092977782462429638d6eb'/>
<id>f98bc68a3244beacf8092977782462429638d6eb</id>
<content type='text'>
commit 614a19b89ca43449196a8af1afac7d55c6781687 upstream.

There is a scenario when resuming from some power saving states
with no_console_suspend where console output can be generated
before the 8250_bcm7271 driver gets the opportunity to restore
the baud_mux_clk frequency. Since the baud_mux_clk is at its
default frequency at this time the output can be garbled until
the driver gets the opportunity to resume.

Since this is only an issue with console use of the serial port
during that window and the console isn't likely to use baud
rates that require alternate baud_mux_clk frequencies, allow the
driver to select the default_mux_rate if it is accurate enough.

Fixes: 41a469482de2 ("serial: 8250: Add new 8250-core based Broadcom STB driver")
Cc: stable@vger.kernel.org
Signed-off-by: Doug Berger &lt;opendmb@gmail.com&gt;
Reviewed-by: Florian Fainelli &lt;florian.fainelli@broadcom.com&gt;
Tested-by: Florian Fainelli &lt;florian.fainelli@broadcom.com&gt;
Link: https://lore.kernel.org/r/20240424222559.1844045-1-opendmb@gmail.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 614a19b89ca43449196a8af1afac7d55c6781687 upstream.

There is a scenario when resuming from some power saving states
with no_console_suspend where console output can be generated
before the 8250_bcm7271 driver gets the opportunity to restore
the baud_mux_clk frequency. Since the baud_mux_clk is at its
default frequency at this time the output can be garbled until
the driver gets the opportunity to resume.

Since this is only an issue with console use of the serial port
during that window and the console isn't likely to use baud
rates that require alternate baud_mux_clk frequencies, allow the
driver to select the default_mux_rate if it is accurate enough.

Fixes: 41a469482de2 ("serial: 8250: Add new 8250-core based Broadcom STB driver")
Cc: stable@vger.kernel.org
Signed-off-by: Doug Berger &lt;opendmb@gmail.com&gt;
Reviewed-by: Florian Fainelli &lt;florian.fainelli@broadcom.com&gt;
Tested-by: Florian Fainelli &lt;florian.fainelli@broadcom.com&gt;
Link: https://lore.kernel.org/r/20240424222559.1844045-1-opendmb@gmail.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>serial: sc16is7xx: fix bug in sc16is7xx_set_baud() when using prescaler</title>
<updated>2024-05-30T07:43:59+00:00</updated>
<author>
<name>Hugo Villeneuve</name>
<email>hvilleneuve@dimonoff.com</email>
</author>
<published>2024-04-30T20:04:30+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=671202e86739557e5612c132883c0246e02655cc'/>
<id>671202e86739557e5612c132883c0246e02655cc</id>
<content type='text'>
commit 8492bd91aa055907c67ef04f2b56f6dadd1f44bf upstream.

When using a high speed clock with a low baud rate, the 4x prescaler is
automatically selected if required. In that case, sc16is7xx_set_baud()
properly configures the chip registers, but returns an incorrect baud
rate by not taking into account the prescaler value. This incorrect baud
rate is then fed to uart_update_timeout().

For example, with an input clock of 80MHz, and a selected baud rate of 50,
sc16is7xx_set_baud() will return 200 instead of 50.

Fix this by first changing the prescaler variable to hold the selected
prescaler value instead of the MCR bitfield. Then properly take into
account the selected prescaler value in the return value computation.

Also add better documentation about the divisor value computation.

Fixes: dfeae619d781 ("serial: sc16is7xx")
Cc: stable@vger.kernel.org
Signed-off-by: Hugo Villeneuve &lt;hvilleneuve@dimonoff.com&gt;
Reviewed-by: Jiri Slaby &lt;jirislaby@kernel.org&gt;
Link: https://lore.kernel.org/r/20240430200431.4102923-1-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 8492bd91aa055907c67ef04f2b56f6dadd1f44bf upstream.

When using a high speed clock with a low baud rate, the 4x prescaler is
automatically selected if required. In that case, sc16is7xx_set_baud()
properly configures the chip registers, but returns an incorrect baud
rate by not taking into account the prescaler value. This incorrect baud
rate is then fed to uart_update_timeout().

For example, with an input clock of 80MHz, and a selected baud rate of 50,
sc16is7xx_set_baud() will return 200 instead of 50.

Fix this by first changing the prescaler variable to hold the selected
prescaler value instead of the MCR bitfield. Then properly take into
account the selected prescaler value in the return value computation.

Also add better documentation about the divisor value computation.

Fixes: dfeae619d781 ("serial: sc16is7xx")
Cc: stable@vger.kernel.org
Signed-off-by: Hugo Villeneuve &lt;hvilleneuve@dimonoff.com&gt;
Reviewed-by: Jiri Slaby &lt;jirislaby@kernel.org&gt;
Link: https://lore.kernel.org/r/20240430200431.4102923-1-hugo@hugovil.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>serial: kgdboc: Fix NMI-safety problems from keyboard reset code</title>
<updated>2024-05-25T14:30:55+00:00</updated>
<author>
<name>Daniel Thompson</name>
<email>daniel.thompson@linaro.org</email>
</author>
<published>2024-04-24T14:21:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=4dd04367a26a48e6b0750322c0c0423a77902858'/>
<id>4dd04367a26a48e6b0750322c0c0423a77902858</id>
<content type='text'>
commit b2aba15ad6f908d1a620fd97f6af5620c3639742 upstream.

Currently, when kdb is compiled with keyboard support, then we will use
schedule_work() to provoke reset of the keyboard status.  Unfortunately
schedule_work() gets called from the kgdboc post-debug-exception
handler.  That risks deadlock since schedule_work() is not NMI-safe and,
even on platforms where the NMI is not directly used for debugging, the
debug trap can have NMI-like behaviour depending on where breakpoints
are placed.

Fix this by using the irq work system, which is NMI-safe, to defer the
call to schedule_work() to a point when it is safe to call.

Reported-by: Liuye &lt;liu.yeC@h3c.com&gt;
Closes: https://lore.kernel.org/all/20240228025602.3087748-1-liu.yeC@h3c.com/
Cc: stable@vger.kernel.org
Reviewed-by: Douglas Anderson &lt;dianders@chromium.org&gt;
Acked-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Link: https://lore.kernel.org/r/20240424-kgdboc_fix_schedule_work-v2-1-50f5a490aec5@linaro.org
Signed-off-by: Daniel Thompson &lt;daniel.thompson@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit b2aba15ad6f908d1a620fd97f6af5620c3639742 upstream.

Currently, when kdb is compiled with keyboard support, then we will use
schedule_work() to provoke reset of the keyboard status.  Unfortunately
schedule_work() gets called from the kgdboc post-debug-exception
handler.  That risks deadlock since schedule_work() is not NMI-safe and,
even on platforms where the NMI is not directly used for debugging, the
debug trap can have NMI-like behaviour depending on where breakpoints
are placed.

Fix this by using the irq work system, which is NMI-safe, to defer the
call to schedule_work() to a point when it is safe to call.

Reported-by: Liuye &lt;liu.yeC@h3c.com&gt;
Closes: https://lore.kernel.org/all/20240228025602.3087748-1-liu.yeC@h3c.com/
Cc: stable@vger.kernel.org
Reviewed-by: Douglas Anderson &lt;dianders@chromium.org&gt;
Acked-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Link: https://lore.kernel.org/r/20240424-kgdboc_fix_schedule_work-v2-1-50f5a490aec5@linaro.org
Signed-off-by: Daniel Thompson &lt;daniel.thompson@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>serial: stm32: Reset .throttled state in .startup()</title>
<updated>2024-04-17T11:26:45+00:00</updated>
<author>
<name>Uwe Kleine-König</name>
<email>u.kleine-koenig@pengutronix.de</email>
</author>
<published>2024-04-17T09:03:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ea2624b5b829b8f93c0dce25721d835969b34faf'/>
<id>ea2624b5b829b8f93c0dce25721d835969b34faf</id>
<content type='text'>
When an UART is opened that still has .throttled set from a previous
open, the RX interrupt is enabled but the irq handler doesn't consider
it. This easily results in a stuck irq with the effect to occupy the CPU
in a tight loop.

So reset the throttle state in .startup() to ensure that RX irqs are
handled.

Fixes: d1ec8a2eabe9 ("serial: stm32: update throttle and unthrottle ops for dma mode")
Cc: stable@vger.kernel.org
Signed-off-by: Uwe Kleine-König &lt;u.kleine-koenig@pengutronix.de&gt;
Link: https://lore.kernel.org/r/a784f80d3414f7db723b2ec66efc56e1ad666cbf.1713344161.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
When an UART is opened that still has .throttled set from a previous
open, the RX interrupt is enabled but the irq handler doesn't consider
it. This easily results in a stuck irq with the effect to occupy the CPU
in a tight loop.

So reset the throttle state in .startup() to ensure that RX irqs are
handled.

Fixes: d1ec8a2eabe9 ("serial: stm32: update throttle and unthrottle ops for dma mode")
Cc: stable@vger.kernel.org
Signed-off-by: Uwe Kleine-König &lt;u.kleine-koenig@pengutronix.de&gt;
Link: https://lore.kernel.org/r/a784f80d3414f7db723b2ec66efc56e1ad666cbf.1713344161.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>serial: stm32: Return IRQ_NONE in the ISR if no handling happend</title>
<updated>2024-04-17T11:26:45+00:00</updated>
<author>
<name>Uwe Kleine-König</name>
<email>u.kleine-koenig@pengutronix.de</email>
</author>
<published>2024-04-17T09:03:27+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=13c785323b36b845300b256d0e5963c3727667d7'/>
<id>13c785323b36b845300b256d0e5963c3727667d7</id>
<content type='text'>
If there is a stuck irq that the handler doesn't address, returning
IRQ_HANDLED unconditionally makes it impossible for the irq core to
detect the problem and disable the irq. So only return IRQ_HANDLED if
an event was handled.

A stuck irq is still problematic, but with this change at least it only
makes the UART nonfunctional instead of occupying the (usually only) CPU
by 100% and so stall the whole machine.

Fixes: 48a6092fb41f ("serial: stm32-usart: Add STM32 USART Driver")
Cc: stable@vger.kernel.org
Signed-off-by: Uwe Kleine-König &lt;u.kleine-koenig@pengutronix.de&gt;
Link: https://lore.kernel.org/r/5f92603d0dfd8a5b8014b2b10a902d91e0bb881f.1713344161.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
If there is a stuck irq that the handler doesn't address, returning
IRQ_HANDLED unconditionally makes it impossible for the irq core to
detect the problem and disable the irq. So only return IRQ_HANDLED if
an event was handled.

A stuck irq is still problematic, but with this change at least it only
makes the UART nonfunctional instead of occupying the (usually only) CPU
by 100% and so stall the whole machine.

Fixes: 48a6092fb41f ("serial: stm32-usart: Add STM32 USART Driver")
Cc: stable@vger.kernel.org
Signed-off-by: Uwe Kleine-König &lt;u.kleine-koenig@pengutronix.de&gt;
Link: https://lore.kernel.org/r/5f92603d0dfd8a5b8014b2b10a902d91e0bb881f.1713344161.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>serial: core: Fix missing shutdown and startup for serial base port</title>
<updated>2024-04-11T12:21:11+00:00</updated>
<author>
<name>Tony Lindgren</name>
<email>tony@atomide.com</email>
</author>
<published>2024-04-11T05:58:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1aa4ad4eb695bac1b0a7ba542a16d6833c9c8dd8'/>
<id>1aa4ad4eb695bac1b0a7ba542a16d6833c9c8dd8</id>
<content type='text'>
We are seeing start_tx being called after port shutdown as noted by Jiri.
This happens because we are missing the startup and shutdown related
functions for the serial base port.

Let's fix the issue by adding startup and shutdown functions for the
serial base port to block tx flushing for the serial base port when the
port is not in use.

Fixes: 84a9582fd203 ("serial: core: Start managing serial controllers to enable runtime PM")
Cc: stable &lt;stable@kernel.org&gt;
Reported-by: Jiri Slaby &lt;jirislaby@kernel.org&gt;
Signed-off-by: Tony Lindgren &lt;tony@atomide.com&gt;
Link: https://lore.kernel.org/r/20240411055848.38190-1-tony@atomide.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
We are seeing start_tx being called after port shutdown as noted by Jiri.
This happens because we are missing the startup and shutdown related
functions for the serial base port.

Let's fix the issue by adding startup and shutdown functions for the
serial base port to block tx flushing for the serial base port when the
port is not in use.

Fixes: 84a9582fd203 ("serial: core: Start managing serial controllers to enable runtime PM")
Cc: stable &lt;stable@kernel.org&gt;
Reported-by: Jiri Slaby &lt;jirislaby@kernel.org&gt;
Signed-off-by: Tony Lindgren &lt;tony@atomide.com&gt;
Link: https://lore.kernel.org/r/20240411055848.38190-1-tony@atomide.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>serial: core: Clearing the circular buffer before NULLifying it</title>
<updated>2024-04-09T15:00:10+00:00</updated>
<author>
<name>Andy Shevchenko</name>
<email>andriy.shevchenko@linux.intel.com</email>
</author>
<published>2024-04-04T14:59:26+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=9cf7ea2eeb745213dc2a04103e426b960e807940'/>
<id>9cf7ea2eeb745213dc2a04103e426b960e807940</id>
<content type='text'>
The circular buffer is NULLified in uart_tty_port_shutdown()
under the spin lock. However, the PM or other timer based callbacks
may still trigger after this event without knowning that buffer pointer
is not valid. Since the serial code is a bit inconsistent in checking
the buffer state (some rely on the head-tail positions, some on the
buffer pointer), it's better to have both aligned, i.e. buffer pointer
to be NULL and head-tail possitions to be the same, meaning it's empty.
This will prevent asynchronous calls to dereference NULL pointer as
reported recently in 8250 case:

  BUG: kernel NULL pointer dereference, address: 00000cf5
  Workqueue: pm pm_runtime_work
  EIP: serial8250_tx_chars (drivers/tty/serial/8250/8250_port.c:1809)
  ...
  ? serial8250_tx_chars (drivers/tty/serial/8250/8250_port.c:1809)
  __start_tx (drivers/tty/serial/8250/8250_port.c:1551)
  serial8250_start_tx (drivers/tty/serial/8250/8250_port.c:1654)
  serial_port_runtime_suspend (include/linux/serial_core.h:667 drivers/tty/serial/serial_port.c:63)
  __rpm_callback (drivers/base/power/runtime.c:393)
  ? serial_port_remove (drivers/tty/serial/serial_port.c:50)
  rpm_suspend (drivers/base/power/runtime.c:447)

The proposed change will prevent -&gt;start_tx() to be called during
suspend on shut down port.

Fixes: 43066e32227e ("serial: port: Don't suspend if the port is still busy")
Cc: stable &lt;stable@kernel.org&gt;
Reported-by: kernel test robot &lt;oliver.sang@intel.com&gt;
Closes: https://lore.kernel.org/oe-lkp/202404031607.2e92eebe-lkp@intel.com
Signed-off-by: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Link: https://lore.kernel.org/r/20240404150034.41648-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The circular buffer is NULLified in uart_tty_port_shutdown()
under the spin lock. However, the PM or other timer based callbacks
may still trigger after this event without knowning that buffer pointer
is not valid. Since the serial code is a bit inconsistent in checking
the buffer state (some rely on the head-tail positions, some on the
buffer pointer), it's better to have both aligned, i.e. buffer pointer
to be NULL and head-tail possitions to be the same, meaning it's empty.
This will prevent asynchronous calls to dereference NULL pointer as
reported recently in 8250 case:

  BUG: kernel NULL pointer dereference, address: 00000cf5
  Workqueue: pm pm_runtime_work
  EIP: serial8250_tx_chars (drivers/tty/serial/8250/8250_port.c:1809)
  ...
  ? serial8250_tx_chars (drivers/tty/serial/8250/8250_port.c:1809)
  __start_tx (drivers/tty/serial/8250/8250_port.c:1551)
  serial8250_start_tx (drivers/tty/serial/8250/8250_port.c:1654)
  serial_port_runtime_suspend (include/linux/serial_core.h:667 drivers/tty/serial/serial_port.c:63)
  __rpm_callback (drivers/base/power/runtime.c:393)
  ? serial_port_remove (drivers/tty/serial/serial_port.c:50)
  rpm_suspend (drivers/base/power/runtime.c:447)

The proposed change will prevent -&gt;start_tx() to be called during
suspend on shut down port.

Fixes: 43066e32227e ("serial: port: Don't suspend if the port is still busy")
Cc: stable &lt;stable@kernel.org&gt;
Reported-by: kernel test robot &lt;oliver.sang@intel.com&gt;
Closes: https://lore.kernel.org/oe-lkp/202404031607.2e92eebe-lkp@intel.com
Signed-off-by: Andy Shevchenko &lt;andriy.shevchenko@linux.intel.com&gt;
Link: https://lore.kernel.org/r/20240404150034.41648-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>serial/pmac_zilog: Remove flawed mitigation for rx irq flood</title>
<updated>2024-04-09T13:57:12+00:00</updated>
<author>
<name>Finn Thain</name>
<email>fthain@linux-m68k.org</email>
</author>
<published>2024-04-08T09:23:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1be3226445362bfbf461c92a5bcdb1723f2e4907'/>
<id>1be3226445362bfbf461c92a5bcdb1723f2e4907</id>
<content type='text'>
The mitigation was intended to stop the irq completely. That may be
better than a hard lock-up but it turns out that you get a crash anyway
if you're using pmac_zilog as a serial console:

ttyPZ0: pmz: rx irq flood !
BUG: spinlock recursion on CPU#0, swapper/0

That's because the pr_err() call in pmz_receive_chars() results in
pmz_console_write() attempting to lock a spinlock already locked in
pmz_interrupt(). With CONFIG_DEBUG_SPINLOCK=y, this produces a fatal
BUG splat. The spinlock in question is the one in struct uart_port.

Even when it's not fatal, the serial port rx function ceases to work.
Also, the iteration limit doesn't play nicely with QEMU, as can be
seen in the bug report linked below.

A web search for other reports of the error message "pmz: rx irq flood"
didn't produce anything. So I don't think this code is needed any more.
Remove it.

Cc: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
Cc: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Cc: Nicholas Piggin &lt;npiggin@gmail.com&gt;
Cc: Christophe Leroy &lt;christophe.leroy@csgroup.eu&gt;
Cc: Aneesh Kumar K.V &lt;aneesh.kumar@kernel.org&gt;
Cc: Naveen N. Rao &lt;naveen.n.rao@linux.ibm.com&gt;
Cc: Andy Shevchenko &lt;andy.shevchenko@gmail.com&gt;
Cc: stable@kernel.org
Cc: linux-m68k@lists.linux-m68k.org
Link: https://github.com/vivier/qemu-m68k/issues/44
Link: https://lore.kernel.org/all/1078874617.9746.36.camel@gaston/
Acked-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable &lt;stable@kernel.org&gt;
Signed-off-by: Finn Thain &lt;fthain@linux-m68k.org&gt;
Link: https://lore.kernel.org/r/e853cf2c762f23101cd2ddec0cc0c2be0e72685f.1712568223.git.fthain@linux-m68k.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The mitigation was intended to stop the irq completely. That may be
better than a hard lock-up but it turns out that you get a crash anyway
if you're using pmac_zilog as a serial console:

ttyPZ0: pmz: rx irq flood !
BUG: spinlock recursion on CPU#0, swapper/0

That's because the pr_err() call in pmz_receive_chars() results in
pmz_console_write() attempting to lock a spinlock already locked in
pmz_interrupt(). With CONFIG_DEBUG_SPINLOCK=y, this produces a fatal
BUG splat. The spinlock in question is the one in struct uart_port.

Even when it's not fatal, the serial port rx function ceases to work.
Also, the iteration limit doesn't play nicely with QEMU, as can be
seen in the bug report linked below.

A web search for other reports of the error message "pmz: rx irq flood"
didn't produce anything. So I don't think this code is needed any more.
Remove it.

Cc: Benjamin Herrenschmidt &lt;benh@kernel.crashing.org&gt;
Cc: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Cc: Nicholas Piggin &lt;npiggin@gmail.com&gt;
Cc: Christophe Leroy &lt;christophe.leroy@csgroup.eu&gt;
Cc: Aneesh Kumar K.V &lt;aneesh.kumar@kernel.org&gt;
Cc: Naveen N. Rao &lt;naveen.n.rao@linux.ibm.com&gt;
Cc: Andy Shevchenko &lt;andy.shevchenko@gmail.com&gt;
Cc: stable@kernel.org
Cc: linux-m68k@lists.linux-m68k.org
Link: https://github.com/vivier/qemu-m68k/issues/44
Link: https://lore.kernel.org/all/1078874617.9746.36.camel@gaston/
Acked-by: Michael Ellerman &lt;mpe@ellerman.id.au&gt;
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable &lt;stable@kernel.org&gt;
Signed-off-by: Finn Thain &lt;fthain@linux-m68k.org&gt;
Link: https://lore.kernel.org/r/e853cf2c762f23101cd2ddec0cc0c2be0e72685f.1712568223.git.fthain@linux-m68k.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>serial: 8250_pci: Remove redundant PCI IDs</title>
<updated>2024-04-09T13:57:01+00:00</updated>
<author>
<name>Andy Shevchenko</name>
<email>andy.shevchenko@gmail.com</email>
</author>
<published>2024-04-03T22:41:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=90452456eb69297fe7ae34e56e40d8e47dc9e019'/>
<id>90452456eb69297fe7ae34e56e40d8e47dc9e019</id>
<content type='text'>
Driver complains that PCI IDs are not needed for some of the LAVA cards:

[    0.297252] serial 0000:04:00.0: Redundant entry in serial pci_table.
[    0.297252] Please send the output of lspci -vv, this
[    0.297252] message (0x1407,0x0120,0x0000,0x0000), the
[    0.297252] manufacturer and name of serial board or
[    0.297252] modem board to &lt;linux-serial@vger.kernel.org&gt;.

Do as suggested.

Reported-by: Jimmy A &lt;jimand04@hotmail.com&gt;
Closes: https://lore.kernel.org/r/VI1P194MB052751BE157EFE9CEAB75725CE362@VI1P194MB0527.EURP194.PROD.OUTLOOK.COM
Signed-off-by: Andy Shevchenko &lt;andy.shevchenko@gmail.com&gt;
Link: https://lore.kernel.org/r/20240403224152.945099-1-andy.shevchenko@gmail.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Driver complains that PCI IDs are not needed for some of the LAVA cards:

[    0.297252] serial 0000:04:00.0: Redundant entry in serial pci_table.
[    0.297252] Please send the output of lspci -vv, this
[    0.297252] message (0x1407,0x0120,0x0000,0x0000), the
[    0.297252] manufacturer and name of serial board or
[    0.297252] modem board to &lt;linux-serial@vger.kernel.org&gt;.

Do as suggested.

Reported-by: Jimmy A &lt;jimand04@hotmail.com&gt;
Closes: https://lore.kernel.org/r/VI1P194MB052751BE157EFE9CEAB75725CE362@VI1P194MB0527.EURP194.PROD.OUTLOOK.COM
Signed-off-by: Andy Shevchenko &lt;andy.shevchenko@gmail.com&gt;
Link: https://lore.kernel.org/r/20240403224152.945099-1-andy.shevchenko@gmail.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
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