linux-stable.git/drivers/tty/serial, branch v7.2.6 Linux kernel stable tree serial: core: clear freed pointers on uart_register_driver() failure 2026-09-14T11:40:13+00:00 Karl Mehltretter kmehltretter@gmail.com 2026-07-31T18:18:41+00:00 06b376432974fe5f25f2843a8e8438c6a1cf3d50 [ Upstream commit 61a2fb25551be0375bc16ef2a70c987dfca26183 ] uart_register_driver() leaves drv->state pointing to freed memory when tty_alloc_driver() fails. If tty_register_driver() fails, drv->tty_driver also retains a pointer after its reference is dropped. Drivers that use drv->state as an "already registered" flag can then skip registration on the next probe and pass the freed state to uart_add_one_port(). This issue was found with failslab on QEMU's raspi1ap board by failing registration and binding the PL011 port again. Clear both pointers on their failure paths, as uart_unregister_driver() already does. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Fixes: 9e845abfc8a8 ("serial: fix NULL pointer dereference") Assisted-by: Claude:claude-fable-5 Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com> Link: https://patch.msgid.link/20260731181844.11330-3-kmehltretter@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 61a2fb25551be0375bc16ef2a70c987dfca26183 ]

uart_register_driver() leaves drv->state pointing to freed memory when
tty_alloc_driver() fails. If tty_register_driver() fails, drv->tty_driver
also retains a pointer after its reference is dropped.

Drivers that use drv->state as an "already registered" flag can then skip
registration on the next probe and pass the freed state to
uart_add_one_port().

This issue was found with failslab on QEMU's raspi1ap board by
failing registration and binding the PL011 port again.

Clear both pointers on their failure paths, as uart_unregister_driver()
already does.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Fixes: 9e845abfc8a8 ("serial: fix NULL pointer dereference")
Assisted-by: Claude:claude-fable-5
Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com>
Link: https://patch.msgid.link/20260731181844.11330-3-kmehltretter@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
serial: core: do fallible allocations before the console can be registered 2026-09-14T11:40:13+00:00 Karl Mehltretter kmehltretter@gmail.com 2026-07-31T18:18:40+00:00 c2aec15f78b2e6ccd9b94216a901248511355982 [ Upstream commit 1a0e4fbce5d9c1bc179a35a2fd9ed142664299e3 ] serial_core_add_one_port() allocates uport->tty_groups after uart_configure_port(), which may register the console. If the allocation fails, the driver unwinds the port while its console remains registered. The earlier uport->name allocation has a related failure path that leaves state->uart_port linked to a port being freed. Failslab reproduced a NULL dereference in PL011 console output and a KASAN use-after-free in i.MX console output after failed binds. Allocate the name and tty_groups before linking the port and configuring it. Reserve space for the optional driver attribute group because config_port() may populate uport->attr_group during configuration. Fixes: 266dcff03eed ("Serial: allow port drivers to have a default attribute group") Fixes: f7048b15900f ("tty: serial_core: Add name field to uart_port struct") Reported-by: Sashiko <sashiko-bot@kernel.org> Closes: https://lore.kernel.org/all/20260719070454.D6FA21F000E9@smtp.kernel.org/ Assisted-by: Claude:claude-fable-5 Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com> Link: https://patch.msgid.link/20260731181844.11330-2-kmehltretter@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 1a0e4fbce5d9c1bc179a35a2fd9ed142664299e3 ]

serial_core_add_one_port() allocates uport->tty_groups after
uart_configure_port(), which may register the console. If the allocation
fails, the driver unwinds the port while its console remains registered.
The earlier uport->name allocation has a related failure path that leaves
state->uart_port linked to a port being freed.

Failslab reproduced a NULL dereference in PL011 console output and a KASAN
use-after-free in i.MX console output after failed binds.

Allocate the name and tty_groups before linking the port and configuring
it. Reserve space for the optional driver attribute group because
config_port() may populate uport->attr_group during configuration.

Fixes: 266dcff03eed ("Serial: allow port drivers to have a default attribute group")
Fixes: f7048b15900f ("tty: serial_core: Add name field to uart_port struct")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Closes: https://lore.kernel.org/all/20260719070454.D6FA21F000E9@smtp.kernel.org/
Assisted-by: Claude:claude-fable-5
Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com>
Link: https://patch.msgid.link/20260731181844.11330-2-kmehltretter@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
serial: amba-pl011: keep console clock enabled for atomic writes 2026-09-14T11:40:13+00:00 Karl Mehltretter kmehltretter@gmail.com 2026-07-24T21:33:48+00:00 2ad24c1d0b939d814a3020f96a667ac2d0394289 [ Upstream commit c0e8cfef754645856374e82c8effd54b7d82002b ] pl011_console_write_atomic() runs from nbcon atomic context, where sleeping is not allowed. It calls clk_enable(), which takes the common-clk enable_lock. Under PREEMPT_RT that is a sleeping lock: clk_enable_lock() first tries spin_trylock_irqsave(), but on contention falls back to spin_lock_irqsave(). Therefore, an atomic-context printk on an RT kernel with a clk-backed pl011 can trip: BUG: sleeping function called from invalid context at spinlock_rt.c:48 __might_resched from rt_spin_lock rt_spin_lock from clk_enable_lock clk_enable_lock from clk_enable clk_enable from pl011_console_write_atomic ... from vprintk_emit This was found and reproduced on PREEMPT_RT. Arm32 and arm64 DT SoCs are affected; arm64 SBSA/ACPI has no clk, so clk_enable(NULL) short-circuits before the lock. In addition, write_atomic() may be invoked from NMI context and is documented to avoid locking. Removing clk_enable() from the callback also avoids a potentially unsafe NMI acquisition of the common-clock enable_lock. An nbcon atomic-capable console must be printable from any context, so the clock cannot be gated between writes. Enable the clock while the console is available for output: use clk_prepare_enable() in pl011_console_setup(), release it via clk_disable_unprepare() in the console .exit() callback, and drop the per-write clk_enable()/clk_disable() pairs from write_atomic() and write_thread(). When printk suspends consoles, drop the reference after uart_suspend_port() stops console access and restore it before uart_resume_port() -- but only if suspend actually marked the port suspended (a wake-capable tty stays running and must keep its clock), and keep it when console_suspend_enabled is false so no_console_suspend works. The active power cost of keeping the clock enabled is platform-dependent: none where the UART clock is a fixed always-on oscillator, real where it is a gateable clock branch, which then cannot be gated (nor possibly can its parent clocks) while the console is available for output. When serial core actually suspends the port, the reference is released so the clock provider can gate the clock tree. Fixes: 2eb2608618ce ("serial: amba-pl011: Implement nbcon console") Suggested-by: John Ogness <john.ogness@linutronix.de> Link: https://lore.kernel.org/all/8733xeaxix.fsf@jogness.linutronix.de/ Assisted-by: Claude:claude-fable-5 Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com> Link: https://patch.msgid.link/20260724213348.77418-3-kmehltretter@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit c0e8cfef754645856374e82c8effd54b7d82002b ]

pl011_console_write_atomic() runs from nbcon atomic context, where
sleeping is not allowed. It calls clk_enable(), which takes the common-clk
enable_lock. Under PREEMPT_RT that is a sleeping lock:
clk_enable_lock() first tries spin_trylock_irqsave(), but on contention
falls back to spin_lock_irqsave(). Therefore, an atomic-context printk on
an RT kernel with a clk-backed pl011 can trip:

  BUG: sleeping function called from invalid context at spinlock_rt.c:48
    __might_resched from rt_spin_lock
    rt_spin_lock from clk_enable_lock
    clk_enable_lock from clk_enable
    clk_enable from pl011_console_write_atomic
    ... from vprintk_emit

This was found and reproduced on PREEMPT_RT. Arm32 and arm64 DT SoCs are
affected; arm64 SBSA/ACPI has no clk, so clk_enable(NULL) short-circuits
before the lock. In addition, write_atomic() may be invoked from NMI
context and is documented to avoid locking. Removing clk_enable() from
the callback also avoids a potentially unsafe NMI acquisition of the
common-clock enable_lock.

An nbcon atomic-capable console must be printable from any context, so
the clock cannot be gated between writes. Enable the clock while the
console is available for output: use clk_prepare_enable() in
pl011_console_setup(), release it via clk_disable_unprepare() in the
console .exit() callback, and drop the per-write clk_enable()/clk_disable()
pairs from write_atomic() and write_thread().

When printk suspends consoles, drop the reference after
uart_suspend_port() stops console access and restore it before
uart_resume_port() -- but only if suspend actually marked the port
suspended (a wake-capable tty stays running and must keep its clock), and
keep it when console_suspend_enabled is false so no_console_suspend works.

The active power cost of keeping the clock enabled is platform-dependent:
none where the UART clock is a fixed always-on oscillator, real where it
is a gateable clock branch, which then cannot be gated (nor possibly can
its parent clocks) while the console is available for output. When serial
core actually suspends the port, the reference is released so the clock
provider can gate the clock tree.

Fixes: 2eb2608618ce ("serial: amba-pl011: Implement nbcon console")
Suggested-by: John Ogness <john.ogness@linutronix.de>
Link: https://lore.kernel.org/all/8733xeaxix.fsf@jogness.linutronix.de/
Assisted-by: Claude:claude-fable-5
Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com>
Link: https://patch.msgid.link/20260724213348.77418-3-kmehltretter@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
serial: amba-pl011: unprepare console clock on unregister 2026-09-14T11:40:13+00:00 Karl Mehltretter kmehltretter@gmail.com 2026-07-24T21:33:47+00:00 0bcf3335dd3b4b575a1835877762ddadd8f9388b [ Upstream commit 7f93da9d78d433c37836d85de475c5d884ad58ed ] pl011_console_setup() calls clk_prepare() on the UART clock, but the console provides no matching teardown, so the clock is never unprepared when the console is unregistered -- via the sysfs "console" attribute or a driver unbind. Each re-registration prepares the clock again, leaking one prepare reference per cycle. Even where preparing the clock has no hardware effect, the stale reference leaves the clock framework's prepare count unbalanced. For providers with prepare/unprepare operations or runtime-PM integration, it may also retain resources after the console is unregistered. Add a console .exit() callback that clk_unprepare()s the clock, balancing the clk_prepare() in pl011_console_setup(). Fixes: 4b4851c65d92 ("clk: amba-pl011: convert to clk_prepare()/clk_unprepare()") Assisted-by: Claude:claude-fable-5 Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com> Link: https://patch.msgid.link/20260724213348.77418-2-kmehltretter@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 7f93da9d78d433c37836d85de475c5d884ad58ed ]

pl011_console_setup() calls clk_prepare() on the UART clock, but the
console provides no matching teardown, so the clock is never unprepared
when the console is unregistered -- via the sysfs "console" attribute or
a driver unbind. Each re-registration prepares the clock again, leaking
one prepare reference per cycle.

Even where preparing the clock has no hardware effect, the stale
reference leaves the clock framework's prepare count unbalanced. For
providers with prepare/unprepare operations or runtime-PM integration,
it may also retain resources after the console is unregistered.

Add a console .exit() callback that clk_unprepare()s the clock,
balancing the clk_prepare() in pl011_console_setup().

Fixes: 4b4851c65d92 ("clk: amba-pl011: convert to clk_prepare()/clk_unprepare()")
Assisted-by: Claude:claude-fable-5
Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com>
Link: https://patch.msgid.link/20260724213348.77418-2-kmehltretter@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Revert "serial: 8250: Clear CON_PRINTBUFFER on port re-registration" 2026-09-14T11:39:56+00:00 Fushuai Wang wangfushuai@baidu.com 2026-07-24T09:31:51+00:00 ba1ee854b681ace60c307fad5ee5f65eb43733c3 [ Upstream commit 57c0741b8c15b93ba4aa92c6618cde6f3f4115b2 ] This reverts commit d338ab1d90603f875c4f7ed223406535378173a5. uart_console() only indicates that the port is selected as the console. It does not mean that the console has already been registered or has printed the buffered messages. On platforms where an initial 8250 port is replaced when the real UART device is registered, clearing CON_PRINTBUFFER causes the console to start at the end of the printk ring buffer. Without earlycon, all messages logged before UART registration are therefore lost. Fixes: d338ab1d9060 ("serial: 8250: Clear CON_PRINTBUFFER on port re-registration") Reported-by: Mark Brown <broonie@kernel.org> Reported-by: Anirudh Srinivasan <asrinivasan@oss.tenstorrent.com> Link: https://lore.kernel.org/all/20260522101042.21976-1-fushuai.wang@linux.dev/ Signed-off-by: Fushuai Wang <wangfushuai@baidu.com> Reviewed-by: John Ogness <john.ogness@linutronix.de> Link: https://patch.msgid.link/20260724093151.53216-1-fushuai.wang@linux.dev Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 57c0741b8c15b93ba4aa92c6618cde6f3f4115b2 ]

This reverts commit d338ab1d90603f875c4f7ed223406535378173a5.

uart_console() only indicates that the port is selected as the console.
It does not mean that the console has already been registered or has
printed the buffered messages.

On platforms where an initial 8250 port is replaced when the real UART
device is registered, clearing CON_PRINTBUFFER causes the console to
start at the end of the printk ring buffer. Without earlycon, all
messages logged before UART registration are therefore lost.

Fixes: d338ab1d9060 ("serial: 8250: Clear CON_PRINTBUFFER on port re-registration")
Reported-by: Mark Brown <broonie@kernel.org>
Reported-by: Anirudh Srinivasan <asrinivasan@oss.tenstorrent.com>
Link: https://lore.kernel.org/all/20260522101042.21976-1-fushuai.wang@linux.dev/
Signed-off-by: Fushuai Wang <wangfushuai@baidu.com>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Link: https://patch.msgid.link/20260724093151.53216-1-fushuai.wang@linux.dev
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
serial: qcom-geni: do not advance stale DMA completions 2026-09-14T11:39:23+00:00 Guangshuo Li lgs201920130244@gmail.com 2026-07-08T13:17:26+00:00 59faa59c25a0a098fbc86275408d7c8405015702 [ Upstream commit 7ea38c49e7178960926657863299face6dc0e1b0 ] The qcom GENI serial DMA TX completion path advances the transmit fifo by the number of bytes recorded in port->tx_remaining. If uart_flush_buffer() runs after the hardware has completed a DMA transfer but before the DMA completion interrupt has been handled, the serial core resets the transmit fifo while port->tx_remaining still describes the old DMA transfer. A previous fix avoided advancing an empty fifo by checking that the fifo length is at least tx_remaining. That still does not distinguish the old DMA payload from new bytes written after the flush. If userspace writes new data before the stale DMA completion interrupt is handled, the fifo can again contain at least tx_remaining bytes and the stale completion can advance and discard those new bytes. Mark an in-flight DMA transfer stale when the transmit fifo is flushed. The later completion still unprepares the original DMA mapping using the saved length, but it no longer advances the transmit fifo. Fixes: 2aaa43c70778 ("tty: serial: qcom-geni-serial: add support for serial engine DMA") Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com> Link: https://patch.msgid.link/20260708131726.768692-1-lgs201920130244@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 7ea38c49e7178960926657863299face6dc0e1b0 ]

The qcom GENI serial DMA TX completion path advances the transmit fifo by
the number of bytes recorded in port->tx_remaining.

If uart_flush_buffer() runs after the hardware has completed a DMA
transfer but before the DMA completion interrupt has been handled, the
serial core resets the transmit fifo while port->tx_remaining still
describes the old DMA transfer.

A previous fix avoided advancing an empty fifo by checking that the fifo
length is at least tx_remaining. That still does not distinguish the old
DMA payload from new bytes written after the flush. If userspace writes
new data before the stale DMA completion interrupt is handled, the fifo
can again contain at least tx_remaining bytes and the stale completion
can advance and discard those new bytes.

Mark an in-flight DMA transfer stale when the transmit fifo is flushed.
The later completion still unprepares the original DMA mapping using the
saved length, but it no longer advances the transmit fifo.

Fixes: 2aaa43c70778 ("tty: serial: qcom-geni-serial: add support for serial engine DMA")
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
Link: https://patch.msgid.link/20260708131726.768692-1-lgs201920130244@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
serial: ma35d1: Fix OF node reference leaks in console init 2026-09-14T11:39:23+00:00 Yuho Choi dbgh9129@gmail.com 2026-06-30T21:40:43+00:00 494bb296407fe75d1643adbb827e0721d98926fc [ Upstream commit 8dfea56f350b3dc826f35711802ad6ae8fae0748 ] ma35d1serial_console_init_port() stores matching UART device nodes in ma35d1serial_uart_nodes[] with an extra of_node_get() so that console setup can later read the "reg" property. However, the stored references are never released after console setup has finished using them. Drop the stored node reference after ma35d1serial_console_setup() reads the "reg" property, and clear the array slot to avoid leaving a stale pointer behind. Also release the iterator reference before breaking out of for_each_matching_node(), since the normal iterator advance will not run in that path. Fixes: 930cbf92db01 ("tty: serial: Add Nuvoton ma35d1 serial driver support") Signed-off-by: Yuho Choi <dbgh9129@gmail.com> Link: https://patch.msgid.link/20260630214043.1887351-1-dbgh9129@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 8dfea56f350b3dc826f35711802ad6ae8fae0748 ]

ma35d1serial_console_init_port() stores matching UART device nodes in
ma35d1serial_uart_nodes[] with an extra of_node_get() so that console
setup can later read the "reg" property.  However, the stored references
are never released after console setup has finished using them.

Drop the stored node reference after ma35d1serial_console_setup() reads
the "reg" property, and clear the array slot to avoid leaving a stale
pointer behind.  Also release the iterator reference before breaking out
of for_each_matching_node(), since the normal iterator advance will not
run in that path.

Fixes: 930cbf92db01 ("tty: serial: Add Nuvoton ma35d1 serial driver support")
Signed-off-by: Yuho Choi <dbgh9129@gmail.com>
Link: https://patch.msgid.link/20260630214043.1887351-1-dbgh9129@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
serial: 8250: Clear CON_PRINTBUFFER on port re-registration 2026-09-14T11:39:23+00:00 Fushuai Wang wangfushuai@baidu.com 2026-05-22T10:10:42+00:00 606f769df00d8c8e4dab2976dd1f1f32632efbaa [ Upstream commit d338ab1d90603f875c4f7ed223406535378173a5 ] When two PnP devices map to the same physical port, the serial8250 driver removes and re-registers the console structure for the same port. During re-registration, the console structure still has CON_PRINTBUFFER set from the initial registration, which causes console_init_seq() to set console->seq to syslog_seq. This results in re-printing the entire system log buffer, which may lead to RCU stall on slow serial consoles. Clear CON_PRINTBUFFER when re-registering a port to prevent duplicate log printing. Fixes: 835d844d1a28 ("8250_pnp: do pnp probe before legacy probe") Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Fushuai Wang <wangfushuai@baidu.com> Link: https://patch.msgid.link/20260522101042.21976-1-fushuai.wang@linux.dev Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit d338ab1d90603f875c4f7ed223406535378173a5 ]

When two PnP devices map to the same physical port, the serial8250 driver
removes and re-registers the console structure for the same port.

During re-registration, the console structure still has CON_PRINTBUFFER set
from the initial registration, which causes console_init_seq() to set
console->seq to syslog_seq. This results in re-printing the entire
system log buffer, which may lead to RCU stall on slow serial consoles.

Clear CON_PRINTBUFFER when re-registering a port to prevent duplicate
log printing.

Fixes: 835d844d1a28 ("8250_pnp: do pnp probe before legacy probe")
Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Fushuai Wang <wangfushuai@baidu.com>
Link: https://patch.msgid.link/20260522101042.21976-1-fushuai.wang@linux.dev
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
serial: imx: serialize imx_uart_ports[] lifetime 2026-09-07T15:36:38+00:00 Karl Mehltretter kmehltretter@gmail.com 2026-07-31T18:18:44+00:00 7429dce56a73bc080a8c072edb167106f73a08ae commit 8b0b29fdcb47907ae0296b8fe829e918e05e300f upstream. imx_uart_probe() publishes its devm-allocated port in imx_uart_ports[] before uart_add_one_port() because console setup uses the table. The entry is not cleared when adding the port fails or after removal, leaving a dangling pointer. A sibling probe can register the shared console through that stale entry. This was reproduced under KASAN on QEMU mcimx6ul-evk by unbinding a sibling UART, unbinding the console UART and rebinding the sibling. Keep the entry valid through uart_remove_one_port(), then clear it. Protect port addition and removal together with their table updates so sibling operations cannot interleave. Reject an occupied slot rather than clobbering an active port during a duplicate-line probe. Fixes: dbff4e9ea2e8 ("IMX UART: remove statically initialized tables") Fixes: 9f322ad064f9 ("imx: serial: handle initialisation failure correctly") Reported-by: Sashiko <sashiko-bot@kernel.org> Link: https://lore.kernel.org/all/20260719162850.043B41F000E9@smtp.kernel.org Link: https://lore.kernel.org/all/20260719222501.CB4CB1F000E9@smtp.kernel.org Cc: stable@vger.kernel.org Assisted-by: Claude:claude-fable-5 Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com> Reviewed-by: Frank Li <Frank.Li@nxp.com> Link: https://patch.msgid.link/20260731181844.11330-6-kmehltretter@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 8b0b29fdcb47907ae0296b8fe829e918e05e300f upstream.

imx_uart_probe() publishes its devm-allocated port in imx_uart_ports[]
before uart_add_one_port() because console setup uses the table. The entry
is not cleared when adding the port fails or after removal, leaving a
dangling pointer.

A sibling probe can register the shared console through that stale entry.
This was reproduced under KASAN on QEMU mcimx6ul-evk by unbinding a
sibling UART, unbinding the console UART and rebinding the sibling.

Keep the entry valid through uart_remove_one_port(), then clear it. Protect
port addition and removal together with their table updates so sibling
operations cannot interleave. Reject an occupied slot rather than
clobbering an active port during a duplicate-line probe.

Fixes: dbff4e9ea2e8 ("IMX UART: remove statically initialized tables")
Fixes: 9f322ad064f9 ("imx: serial: handle initialisation failure correctly")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Link: https://lore.kernel.org/all/20260719162850.043B41F000E9@smtp.kernel.org
Link: https://lore.kernel.org/all/20260719222501.CB4CB1F000E9@smtp.kernel.org
Cc: stable@vger.kernel.org
Assisted-by: Claude:claude-fable-5
Signed-off-by: Karl Mehltretter <kmehltretter@gmail.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260731181844.11330-6-kmehltretter@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
serial: amba-pl011: synchronize DMA teardown 2026-08-03T14:31:22+00:00 Fan Wu fanwu01@zju.edu.cn 2026-07-31T08:59:15+00:00 440915499231e9db1c361aa45bb702e8fd3b4a32 dmaengine_terminate_all() does not wait for a running callback, so the TX callback can still touch the TX buffer after it is freed. The RX poll timer reads the RX buffers without the port lock. Switch to dmaengine_terminate_sync() and delete the RX timer before freeing the buffers. Fixes: ead76f329f77 ("ARM: 6763/1: pl011: add optional RX DMA to PL011 v2") Cc: stable <stable@kernel.org> Assisted-by: Codex:gpt-5.6 Signed-off-by: Fan Wu <fanwu01@zju.edu.cn> Link: https://patch.msgid.link/20260731085915.326775-4-fanwu01@zju.edu.cn Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
dmaengine_terminate_all() does not wait for a running callback, so the TX
callback can still touch the TX buffer after it is freed. The RX poll
timer reads the RX buffers without the port lock.

Switch to dmaengine_terminate_sync() and delete the RX timer before
freeing the buffers.

Fixes: ead76f329f77 ("ARM: 6763/1: pl011: add optional RX DMA to PL011 v2")
Cc: stable <stable@kernel.org>
Assisted-by: Codex:gpt-5.6
Signed-off-by: Fan Wu <fanwu01@zju.edu.cn>
Link: https://patch.msgid.link/20260731085915.326775-4-fanwu01@zju.edu.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>