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6 daysserial: amba-pl011: synchronize DMA teardownFan Wu1-4/+4
[ Upstream commit 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> [ changed upstream's `timer_delete_sync()` deletion to match this tree's `del_timer_sync()` spelling at the old call site ] Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
10 daysserial: sc16is7xx: implement gpio get_direction() callbackHugo Villeneuve1-0/+12
[ Upstream commit af071d9e07e57cfff239e8d09d2f3b05ebc9c667 ] It's strongly recommended for GPIO drivers to always implement the .get_direction() callback - even when the direction is tracked in software. The GPIO core emits a warning when the callback is missing and a user reads the direction of a line, e.g. via /sys/kernel/debug/gpio. Fixes: dfeae619d781 ("serial: sc16is7xx") Cc: stable <stable@kernel.org> Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com> Acked-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com> Link: https://patch.msgid.link/20260716210813.2582826-1-hugo@hugovil.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
10 daysserial: sc16is7xx: fix regression with GPIO configurationHugo Villeneuve1-19/+105
[ Upstream commit 0499942928341d572a42199580433c2b0725211e ] Commit 679875d1d880 ("sc16is7xx: Separate GPIOs from modem control lines") and commit 21144bab4f11 ("sc16is7xx: Handle modem status lines") changed the function of the GPIOs pins to act as modem control lines without any possibility of selecting GPIO function. As a consequence, applications that depends on GPIO lines configured by default as GPIO pins no longer work as expected. Also, the change to select modem control lines function was done only for channel A of dual UART variants (752/762). This was not documented in the log message. Allow to specify GPIO or modem control line function in the device tree, and for each of the ports (A or B). Do so by using the new device-tree property named "nxp,modem-control-line-ports" (property added in separate patch). When registering GPIO chip controller, mask-out GPIO pins declared as modem control lines according to this new DT property. Fixes: 679875d1d880 ("sc16is7xx: Separate GPIOs from modem control lines") Fixes: 21144bab4f11 ("sc16is7xx: Handle modem status lines") Cc: stable@vger.kernel.org Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Reviewed-by: Lech Perczak <lech.perczak@camlingroup.com> Tested-by: Lech Perczak <lech.perczak@camlingroup.com> Acked-by: Rob Herring <robh@kernel.org> Link: https://lore.kernel.org/r/20230807214556.540627-5-hugo@hugovil.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Stable-dep-of: af071d9e07e5 ("serial: sc16is7xx: implement gpio get_direction() callback") Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
10 daysserial: sc16is7xx: remove obsolete out_thread labelHugo Villeneuve1-3/+1
[ Upstream commit dabc54a45711fe77674a6c0348231e00e66bd567 ] Commit c8f71b49ee4d ("serial: sc16is7xx: setup GPIO controller later in probe") moved GPIO setup code later in probe function. Doing so also required to move ports cleanup code (out_ports label) after the GPIO cleanup code. After these moves, the out_thread label becomes misplaced and makes part of the cleanup code illogical. This patch remove the now obsolete out_thread label and make GPIO setup code jump to out_ports label if it fails. Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com> Reviewed-by: Lech Perczak <lech.perczak@camlingroup.com> Tested-by: Lech Perczak <lech.perczak@camlingroup.com> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Link: https://lore.kernel.org/r/20230807214556.540627-3-hugo@hugovil.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Stable-dep-of: af071d9e07e5 ("serial: sc16is7xx: implement gpio get_direction() callback") Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
10 daysserial: sc16is7xx: Fill in rs485_supportedIlpo Järvinen1-0/+7
[ Upstream commit 267913ecf73745ca3e8fc8282671b0b4f24df5fe ] Add information on supported serial_rs485 features. This driver does not support delay_rts_after_send but the pre-existing behavior is to return -EINVAL if delay_rts_after_send is non-zero. In contrast, other drivers that do not support delay_rts_after_send either zero delay_rts_after_send or do not care (leave the inaccurate value). As changing this would cause userspace visible impact, the change is not attempted here. But perhaps it should be still tried (maybe nobody finds that kind of API oddity significant)? Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20220606100433.13793-21-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Stable-dep-of: af071d9e07e5 ("serial: sc16is7xx: implement gpio get_direction() callback") Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
10 dayssc16is7xx: Properly resume TX after stopTomasz Moń1-6/+41
[ Upstream commit cc4c1d05eb10c3ad4c6315f1897bc56b1e7429aa ] sc16is7xx_stop_tx() clears THRI bit and thus disables THRI interrupt. This makes it possible for transmission to cease indefinitely when more than 64 characters are being sent. The sc16is7xx_handle_tx() call executed by sc16is7xx_tx_proc() can send up to FIFO length (64) characters. If more characters are written to the output buffer, then the THRI interrupt is needed. Solve the issue by enabling THRI interrupt in sc16is7xx_tx_proc(). Signed-off-by: Tomasz Moń <tomasz.mon@camlingroup.com> Link: https://lore.kernel.org/r/20220301060332.2561851-2-tomasz.mon@camlingroup.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Stable-dep-of: af071d9e07e5 ("serial: sc16is7xx: implement gpio get_direction() callback") Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
10 daysserial: 8250_mid: Fix NULL function pointer dereference on DNV/ICX-D/SNR ↵Jiangshan Yi1-5/+9
platforms [ Upstream commit 7fb13fd7e9a59a37cd911efff83abe19e3ee029d ] Commit b1b4efea05a5 ("serial: 8250_mid: Disable DMA for selected platforms") replaced the dnv_board setup and exit callbacks with PTR_IF(false, ...), which evaluates to NULL. However, the three call sites in mid8250_probe() and mid8250_remove() unconditionally dereference these function pointers without NULL checks, causing a NULL pointer dereference (kernel oops) on any Denverton (DNV), Ice Lake Xeon D (ICX-D/CDF), or Snowridge (SNR) platform. Fix this by adding the missing NULL checks before calling the setup and exit callbacks. Fixes: b1b4efea05a5 ("serial: 8250_mid: Disable DMA for selected platforms") Cc: stable <stable@kernel.org> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Jiangshan Yi <yijiangshan@kylinos.cn> Link: https://patch.msgid.link/20260715073546.1875083-1-yijiangshan@kylinos.cn Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
10 daysserial: 8250_mid: Remove unneeded test for ->setup() presenceAndy Shevchenko1-5/+3
[ Upstream commit 324facd1ccb353a213ea2c2785604f2507f79297 ] All supported platforms by this driver require ->setup() and ->exit(). Remove unneeded test for ->setup() presence. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20220215101111.47250-1-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Stable-dep-of: 7fb13fd7e9a5 ("serial: 8250_mid: Fix NULL function pointer dereference on DNV/ICX-D/SNR platforms") Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
10 daysserial: max310x: implement gpio_chip::get_direction()Tapio Reijonen1-0/+12
[ Upstream commit a483b1a91b33b7533280e7c3efd2bc1275caef18 ] It's strongly recommended for GPIO drivers to always implement the .get_direction() callback - even when the direction is tracked in software. The GPIO core emits a warning when the callback is missing and a user reads the direction of a line, e.g. via /sys/kernel/debug/gpio. The MAX310X keeps the GPIO direction in the GPIOCFG register (a set bit selects output), which the existing direction_input/output callbacks already program, so the current direction can be read back directly. Fixes: f65444187a66 ("serial: New serial driver MAX310X") Cc: stable <stable@kernel.org> Signed-off-by: Tapio Reijonen <tapio.reijonen@vaisala.com> Reviewed-by: Linus Walleij <linusw@kernel.org> Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com> Reviewed-by: Hugo Villeneuve <hvilleneuve@dimonoff.com> Link: https://patch.msgid.link/20260615-b4-serial-max310x-gpio-get-direction-v2-1-4704ba2b181a@vaisala.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
10 daysserial: max310x: replace bare use of 'unsigned' with 'unsigned int' (checkpatch)Hugo Villeneuve1-4/+4
[ Upstream commit 79b69eb09cf5b6a77e621b2838b7e0d38113debb ] Fixes the following checkpatch warnings: WARNING: Prefer 'unsigned int' to bare use of 'unsigned' With this change, the affected functions now match the prototypes in struct gpio_chip. Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com> Link: https://lore.kernel.org/r/20240118152213.2644269-16-hugo@hugovil.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Stable-dep-of: a483b1a91b33 ("serial: max310x: implement gpio_chip::get_direction()") Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
14 daysserial: 8250_dma: Clear stale RX state on shutdownCunhao Lu1-5/+7
commit e2fe6a0efecbef00e3ecc2db64dd5afa8c212b41 upstream. serial8250_release_dma() terminates RX DMA and releases the channel, but leaves rx_running set. If the port is closed while an RX transfer is active, the stale state remains while rxchan is NULL until the channel is requested again on the next open. The DesignWare BUSY workaround added by commit a7b9ce39fbe4 ("serial: 8250_dw: Ensure BUSY is deasserted") calls serial8250_rx_dma_flush() from the LCR write path during startup. This happens before serial8250_request_dma() obtains a new RX channel. On reopen, the stale rx_running state therefore makes the flush path pass a NULL channel to dmaengine_pause(), causing a kernel Oops. Clear rx_running after terminating RX DMA, matching the TX cleanup. Also make the flush helper return if the DMA object or RX channel is not available so startup and teardown paths cannot pass a NULL channel to the DMAengine API. Fixes: 0fcb7901f9d6 ("tty: serial: 8250_dma: keep own book keeping about RX transfers") Cc: stable <stable@kernel.org> Signed-off-by: Cunhao Lu <1579567540@qq.com> Link: https://patch.msgid.link/tencent_9EE2945F4C933B4D810C73C2D7485E000F06@qq.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
14 daysvt: stabilize tty reference in kbd_keycode with tty_port_tty_getJoshua Rogers1-1/+4
commit e25d47a526939ad44b75f778b8a7500562b84fc1 upstream. kbd_keycode() reads vc->port.tty without acquiring a tty reference, racing against con_shutdown() which clears port.tty under a different lock. Use tty_port_tty_get()/tty_kref_put() to hold a proper reference for the duration the tty pointer is needed. Assisted-by: AISLE:Snapshot Signed-off-by: Joshua Rogers <linux@joshua.hu> Cc: stable <stable@kernel.org> Link: https://patch.msgid.link/20260731-tty-vt-stuff-v1-1-be99b9da8e30@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
14 daysvt: add permission check for KDSKBMETA ioctlJoshua Rogers1-0/+2
commit a7ad0034453ba4c353f9b8f810ee2569de33d283 upstream. KDSKBMETA modifies keyboard meta mode but lacks the !perm check that all other keyboard setter ioctls in vt_k_ioctl() enforce, allowing a process to change meta mode on a non-controlling console without authorization. Assisted-by: AISLE:Snapshot Cc: stable <stable@kernel.org> Signed-off-by: Joshua Rogers <linux@joshua.hu> Link: https://patch.msgid.link/20260731-tty-vt-stuff-v1-2-be99b9da8e30@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-07-24serial: 8250_mid: Disable DMA for selected platformsAndy Shevchenko1-2/+11
[ Upstream commit b1b4efea05a56c0995e4702a86d6624b4fdff32f ] In accordance with Errata (specification updates) HSUART May Stop Functioning when DMA is Active. - Denverton document #572409, rev 3.4, DNV60 - Ice Lake Xeon D document #714070, ICXD65 - Snowridge document #731931, SNR44 For a quick fix just disable the respective callbacks during the device probe. Depending on the future development we might remove them completely. Reported-by: micas-opensource <zjianan156@gmail.com> Closes: https://lore.kernel.org/linux-serial/20250625031409.2404219-1-opensource@ruijie.com.cn/ Fixes: 6ede6dcd87aa ("serial: 8250_mid: add support for DMA engine handling from UART MMIO") Cc: stable <stable@kernel.org> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://patch.msgid.link/20260626094937.561776-1-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-07-24serial: 8250_mid: Remove 8250_pci usageIlpo Järvinen1-11/+7
[ Upstream commit a136abd7e7abe0f1247f8ffde6cc7c8ab09f985b ] 8250_mid uses FL_*BASE* from linux/8250_pci.h and nothing else. The code can be simplified by directly defining BARs within the driver instead. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/20230915094336.13278-1-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Stable-dep-of: b1b4efea05a5 ("serial: 8250_mid: Disable DMA for selected platforms") Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-07-24serial: 8250_omap: clear rx_running on zero-length DMA completesMatthias Feser1-1/+2
commit 061b627ba534230a18ec4d7251562af12325d06a upstream. On AM33xx RX DMA only triggers when the FIFO reaches the configured threshold (typically 48 bytes). For smaller bursts no DMA request is issued and the FIFO is drained by RX timeout. In this case __dma_rx_do_complete() can legitimately see count == 0. The current code exits early in this case and does not clear dma->rx_running, leaving the DMA state inconsistent. This can prevent RX DMA from restarting and may cause omap_8250_rx_dma_flush() to fail, marking DMA as broken. Fix this by clearing dma->rx_running once the DMA transfer has completed or been terminated, even if no data was transferred. Fixes: a5fd8945a478 ("serial: 8250: 8250_omap.c: Clear DMA RX running status only after DMA termination is done") Cc: stable <stable@kernel.org> Signed-off-by: Matthias Feser <mfe@KBSgmbhfr.onmicrosoft.com> Reviewed-by: Moteen Shah <m-shah@ti.com> Link: https://patch.msgid.link/BE3P281MB55155F2F5795E411F5A65282EE0B2@BE3P281MB5515.DEUP281.PROD.OUTLOOK.COM Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-07-24serial: msm: Disable DMA for kernel console UARTStephan Gerhold1-1/+2
commit 22dd2777e6c180e1c945b00f6d18550979436324 upstream. At the moment, concurrent writes from userspace and the kernel to the console can trigger a race condition that results in an infinite loop of the same messages printed over and over again. This is most likely to happen during system startup or shutdown when the init system starts/stops a large number of system services that interact with various kernel code. When userspace writes to the TTY device, the driver initiates an asynchronous DMA transfer and releases the port lock. At the same moment, the kernel printk path might grab the port lock and re-configure the UART controller for PIO, without waiting for the DMA operation to complete. It seems like this collision results in zero progress being reported for the DMA engine, so the same text is printed to the console over and over again. For the kernel console, we want a reliable output path that will be functional even during crashes etc. So rather than implementing complex code to synchronize the kernel console write routines with the userspace DMA write routines, simply disable DMA for the console UART instance. Similar checks exist in many other serial drivers, e.g. 8250_port.c, imx.c, sh-sci.c etc. Cc: stable <stable@kernel.org> Fixes: 3a878c430fd6 ("tty: serial: msm: Add TX DMA support") Signed-off-by: Stephan Gerhold <stephan.gerhold@linaro.org> Acked-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com> Link: https://patch.msgid.link/20260706-serial-msm-console-dma-collision-v1-1-3179b8cb1d89@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-07-04vc_screen: fix null-ptr-deref in vcs_notifier() during concurrent vcs_writeYi Yang1-1/+1
commit a287620312dc6dcb9a093417a0e589bf30fcf38a upstream. A KASAN null-ptr-deref was observed in vcs_notifier(): BUG: KASAN: null-ptr-deref in vcs_notifier+0x98/0x130 Read of size 2 at addr qmp_cmd_name: qmp_capabilities, arguments: {} The issue is a race condition in vcs_write(). When the console_lock is temporarily dropped (to copy data from userspace), the vc_data pointer obtained from vcs_vc() may become stale. After re-acquiring the lock, vcs_vc() is called again to re-validate the pointer. If the vc has been deallocated in the meantime, vcs_vc() returns NULL, and the while loop breaks (with written > 0). However, after the loop, vcs_scr_updated(vc) is still called with the now-NULL vc pointer, leading to a null pointer dereference in the notifier chain (vcs_notifier dereferences param->vc). Fix this by adding a NULL check for vc before calling vcs_scr_updated(). Fixes: 8fb9ea65c9d1 ("vc_screen: reload load of struct vc_data pointer in vcs_write() to avoid UAF") Cc: stable@vger.kernel.org Signed-off-by: Yi Yang <yiyang13@huawei.com> Reviewed-by: Jiri Slaby <jirislaby@kernel.org> Link: https://patch.msgid.link/20260604060734.2914976-1-yiyang13@huawei.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-06-19serial: qcom-geni: fix UART_RX_PAR_EN bit positionPrasanna S1-1/+1
[ Upstream commit ca2584d841b69391ffc4144840563d2e1a0018df ] UART_RX_PAR_EN is incorrectly defined as bit 3, which triggers false framing errors (S_GP_IRQ_1_EN) and causes received data to be dropped when parity is enabled and the parity bit is 0. Define UART_RX_PAR_EN as bit 4 of the SE_UART_RX_TRANS_CFG register, as specified in the reference manual. Fixes: c4f528795d1a ("tty: serial: msm_geni_serial: Add serial driver support for GENI based QUP") Cc: stable <stable@kernel.org> Signed-off-by: Prasanna S <prasanna.s@oss.qualcomm.com> Reviewed-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com> Link: https://patch.msgid.link/20260428-serial-bit-correct-v1-1-9131ad5b97d8@oss.qualcomm.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-06-19tty: serial: qcom-geni-serial: align #define valuesBartosz Golaszewski1-31/+31
[ Upstream commit 6cde11dbf4b65170eeefba48df730c93d75e01a3 ] Keep the #define symbols aligned for better readability. Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org> Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org> Link: https://lore.kernel.org/r/20221229155030.418800-5-brgl@bgdev.pl Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Stable-dep-of: ca2584d841b6 ("serial: qcom-geni: fix UART_RX_PAR_EN bit position") Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-06-19tty: serial: qcom-geni-serial: remove unused symbolsBartosz Golaszewski1-15/+0
[ Upstream commit 68c6bd92c86cbc4937834c79963b27c77ee3bf51 ] Drop all unused symbols from the driver. Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org> Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org> Link: https://lore.kernel.org/r/20221229155030.418800-4-brgl@bgdev.pl Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Stable-dep-of: ca2584d841b6 ("serial: qcom-geni: fix UART_RX_PAR_EN bit position") Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-06-19serial: altera_jtaguart: handle uart_add_one_port() failuresMyeonghun Pak1-1/+6
[ Upstream commit ea66be25f0e934f49d24cd0c5845d13cdba3520b ] altera_jtaguart_probe() maps the register window before registering the UART port, but it ignores failures from uart_add_one_port(). If port registration fails, probe still returns success and the mapping remains live until a later remove path that is not part of probe failure cleanup. Return the uart_add_one_port() error and unmap the register window on that failure path. This issue was identified during our ongoing static-analysis research while reviewing kernel code. Fixes: 5bcd601049c6 ("serial: Add driver for the Altera JTAG UART") Cc: stable <stable@kernel.org> Co-developed-by: Ijae Kim <ae878000@gmail.com> Signed-off-by: Ijae Kim <ae878000@gmail.com> Signed-off-by: Myeonghun Pak <mhun512@gmail.com> Link: https://patch.msgid.link/20260512065837.79528-1-mhun512@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-06-19serial: altera_jtaguart: Use platform_get_irq_optional() to get the interruptLad Prabhakar1-4/+7
[ Upstream commit 60302276caff50f907bc3391a364691ab4a21b43 ] platform_get_resource(pdev, IORESOURCE_IRQ, ..) relies on static allocation of IRQ resources in DT core code, this causes an issue when using hierarchical interrupt domains using "interrupts" property in the node as this bypasses the hierarchical setup and messes up the irq chaining. In preparation for removal of static setup of IRQ resource from DT core code use platform_get_irq_optional(). Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> Link: https://lore.kernel.org/r/20211224142917.6966-7-prabhakar.mahadev-lad.rj@bp.renesas.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Stable-dep-of: ea66be25f0e9 ("serial: altera_jtaguart: handle uart_add_one_port() failures") Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-06-19tty: serial: samsung: Remove redundant port lock acquisition in rx helpersTudor Ambarus1-8/+0
[ Upstream commit a3bb136bff5e6a5e48cdd813246c9c4686feaaa9 ] Sashiko identified a deadlock when the console flow is engaged [1]. When console flow control is enabled (UPF_CONS_FLOW), s3c24xx_serial_stop_tx() calls s3c24xx_serial_rx_enable() and s3c24xx_serial_start_tx() calls s3c24xx_serial_rx_disable(). The serial core framework invokes the .stop_tx() and .start_tx() callbacks with the port->lock spinlock already held. Furthermore, all internal driver paths that invoke stop_tx (such as the DMA TX completion handler s3c24xx_serial_tx_dma_complete() or the PIO TX IRQ handler s3c24xx_serial_tx_irq()) also acquire port->lock prior to calling it. (Note that s3c24xx_serial_start_tx() is only invoked by the serial core). However, s3c24xx_serial_rx_enable() and s3c24xx_serial_rx_disable() unconditionally attempt to acquire port->lock again using uart_port_lock_irqsave(). Since spinlocks are not recursive, this causes a deadlock on the same CPU when console flow control is engaged. Remove the redundant lock acquisition from both rx helper functions. Cc: stable <stable@kernel.org> Fixes: b497549a035c ("[ARM] S3C24XX: Split serial driver into core and per-cpu drivers") Reported-by: John Ogness <john.ogness@linutronix.de> Closes: https://sashiko.dev/#/patchset/20260506121606.5805-1-john.ogness%40linutronix.de [1] Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org> Link: https://patch.msgid.link/20260515-samsung-tty-flow-control-deadlock-v1-1-93255edbc9bc@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-06-19tty: serial: samsung: use u32 for register interactionsTudor Ambarus1-23/+21
[ Upstream commit 032a725c16add79332d774348d7ad7d0d4b86479 ] All registers of the IP have 32 bits. Use u32 variables when reading or writing from/to the registers. The purpose of those variables becomes clearer. Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org> Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org> Link: https://lore.kernel.org/r/20240119104526.1221243-9-tudor.ambarus@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Stable-dep-of: a3bb136bff5e ("tty: serial: samsung: Remove redundant port lock acquisition in rx helpers") Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-06-19serial: samsung_tty: Use port lock wrappersThomas Gleixner1-22/+22
[ Upstream commit 97d7a9aeba1d424c2359f1686d02c75d798ad184 ] When a serial port is used for kernel console output, then all modifications to the UART registers which are done from other contexts, e.g. getty, termios, are interference points for the kernel console. So far this has been ignored and the printk output is based on the principle of hope. The rework of the console infrastructure which aims to support threaded and atomic consoles, requires to mark sections which modify the UART registers as unsafe. This allows the atomic write function to make informed decisions and eventually to restore operational state. It also allows to prevent the regular UART code from modifying UART registers while printk output is in progress. All modifications of UART registers are guarded by the UART port lock, which provides an obvious synchronization point with the console infrastructure. To avoid adding this functionality to all UART drivers, wrap the spin_[un]lock*() invocations for uart_port::lock into helper functions which just contain the spin_[un]lock*() invocations for now. In a subsequent step these helpers will gain the console synchronization mechanisms. Converted with coccinelle. No functional change. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Ogness <john.ogness@linutronix.de> Link: https://lore.kernel.org/r/20230914183831.587273-54-john.ogness@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Stable-dep-of: a3bb136bff5e ("tty: serial: samsung: Remove redundant port lock acquisition in rx helpers") Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-06-19serial: dz: Fix bootconsole handover lockupMaciej W. Rozycki1-24/+13
commit 7f127b2208e5e2b817243cad41fe4211a6d5a7a3 upstream. Calling dz_reset() in the course of setting up the serial device causes line parameters to be reset and the transmitter disabled. We've been lucky in that no message is usually produced to the kernel log between this call and the later call to uart_set_options() in the course of console setup done by dz_serial_console_init(), or the system would hang as the console output handler in the firmware tried to access a port the transmitter of which has been disabled and line parameters messed up. This will change with the next change to the driver, so fix dz_reset() such that line parameters are set for 9600n8 console operation as with the system firmware and the transmitter re-enabled after reset. This also means dz_pm() serves no purpose anymore, so drop it. Fixes: e6ee512f5a77 ("dz.c: Resource management") Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk> Cc: stable@vger.kernel.org # v2.6.25+ Link: https://patch.msgid.link/alpine.DEB.2.21.2605062302010.46195@angie.orcam.me.uk Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ Avoid C99+ 'for' loop initial declaration for 5.15.y. ] Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-06-19serial: zs: Switch to using channel resetMaciej W. Rozycki2-4/+5
commit 8572955630f30948837088aa98bcbe0532d1ceac upstream. Switch the driver to using the channel reset rather than hardware reset, simplifying handling by removing an interference between channels that causes the other channel to become uninitialised afterwards. There is little difference between the two kinds of reset in terms of register settings that result, and we initialise the whole register set right away anyway. However this prevents a hang from happening should the console output handler in the firmware try to access the other port whose transmitter has been disabled and line parameters messed up. For example this will happen if the keyboard port (port A) is chosen for the system console, unusually but not insanely for a headless system, as the port is wired to a standard DA-15 connector and an adapter can be easily made. Or with the next change in place this would happen for the regular console port (port B), since the keyboard port (port A) will be initialised first. Just remove the unnecessary complication then, a channel reset is good enough. We still need the initialisation marker, now per channel rather than per SCC, as for the console port zs_reset() will be called twice: once early on via zs_serial_console_init() for the console setup only, and then again via zs_config_port() as the port is associated with a TTY device. Fixes: 8b4a40809e53 ("zs: move to the serial subsystem") Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk> Cc: stable@vger.kernel.org # v2.6.23+ Link: https://patch.msgid.link/alpine.DEB.2.21.2605062323430.46195@angie.orcam.me.uk Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-06-19serial: zs: Fix bootconsole handover lockupMaciej W. Rozycki1-21/+8
commit 6c05cf72e13314ce9b770b5951695dc5a2152920 upstream. Calling zs_reset() in the course of setting up the serial device causes line parameters to be reset and the transmitter disabled. We've been lucky in that no message is usually produced to the kernel log between this call and the later call to uart_set_options() in the course of console setup done by zs_serial_console_init(), or the system would hang as the console output handler in the firmware tried to access a port the transmitter of which has been disabled and line parameters messed up. This will change with the next change to the driver, so fix zs_reset() such that line parameters are set for 9600n8 console operation as with the system firmware and the transmitter re-enabled after reset. This also means zs_pm() serves no purpose anymore, so drop it. Fixes: 8b4a40809e53 ("zs: move to the serial subsystem") Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk> Cc: stable@vger.kernel.org # v2.6.23+ Link: https://patch.msgid.link/alpine.DEB.2.21.2605062308040.46195@angie.orcam.me.uk Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-06-19serial: dz: Fix bootconsole message clobbering at chip resetMaciej W. Rozycki1-0/+21
commit ca904f4b42355287bc5ce8b7550ebe909cda4c2c upstream. In the DZ interface as implemented by the DC7085 gate array the serial transmitters are double buffered, meaning that at the time a transmitter is ready to accept the next character there is one in the transmit shift register still being sent to the line. Issuing a master clear at this time causes this character to be lost, so wait an extra amount of time sufficient for the transmit shift register to drain at 9600bps, which is the baud rate setting used by the firmware console. Mind the specified 1.4us TRDY recovery time in the course and continue using iob() as the completion barrier, since the platforms involved use a write buffer that can delay and combine writes, and reorder them with respect to reads regardless of the MMIO locations accessed and we still lack a platform-independent handler for that. When called from dz_serial_console_init() this is too early for fsleep() to work and even before lpj has been calculated and therefore the delay is actually not sufficient for the transmitter to drain and is merely a placeholder now. This will be addressed in a follow-up change. Fixes: e6ee512f5a77 ("dz.c: Resource management") Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk> Cc: stable@vger.kernel.org # v2.6.25+ Link: https://patch.msgid.link/alpine.DEB.2.21.2605062259080.46195@angie.orcam.me.uk Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-06-19serial: fsl_lpuart: fix rx buffer and DMA map leaks in start_rx_dmaShitalkumar Gandhi1-3/+12
commit 9a9254c4a2a3ca2b3da16d173f3b0dd01f397ff6 upstream. lpuart_start_rx_dma() allocates sport->rx_ring.buf with kzalloc() and then maps a scatterlist via dma_map_sg(). On three subsequent error paths the function returns directly without releasing those resources: - when dma_map_sg() returns 0 (-EINVAL): ring->buf is leaked. - when dmaengine_slave_config() fails: ring->buf and the DMA mapping are leaked. - when dmaengine_prep_dma_cyclic() returns NULL: ring->buf and the DMA mapping are leaked. The sole cleanup path, lpuart_dma_rx_free(), is only reached when lpuart_dma_rx_use is set, and the caller lpuart_rx_dma_startup() clears that flag on failure of lpuart_start_rx_dma(). So these resources are permanently leaked on every failure in this function. Repeated port open/close or termios changes under error conditions will slowly consume memory and leave stale streaming DMA mappings behind. Fix it by introducing two error labels that unmap the scatterlist and free the ring buffer as appropriate. While here, replace the misleading -EFAULT (bad userspace pointer) returned when dmaengine_prep_dma_cyclic() fails with the more accurate -ENOMEM, matching how other dmaengine users in the tree treat this failure. No functional change on the success path. Fixes: 5887ad43ee02 ("tty: serial: fsl_lpuart: Use cyclic DMA for Rx") Cc: stable <stable@kernel.org> Signed-off-by: Shitalkumar Gandhi <shitalkumar.gandhi@cambiumnetworks.com> Reviewed-by: Frank Li <Frank.Li@nxp.com> Link: https://patch.msgid.link/20260420135903.2062024-1-shitalkumar.gandhi@cambiumnetworks.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-06-19serial: zs: Fix swapped RI/DSR modem line transition countingMaciej W. Rozycki1-2/+2
commit d15cd40cb1858f75846eaafa9a6bca841b790a92 upstream. Fix a thinko in the status interrupt handler that has caused counters for the RI and DSR modem line transitions to be used for the other line each. Fixes: 8b4a40809e53 ("zs: move to the serial subsystem") Cc: stable <stable@kernel.org> Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk> Link: https://patch.msgid.link/alpine.DEB.2.21.2604101747110.29980@angie.orcam.me.uk Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-06-19serial: sh-sci: fix memory region release in error pathHongling Zeng1-1/+1
commit 92b1ea22454b08a39baef3a7290fb3ec50366616 upstream. The sci_request_port() function uses request_mem_region() to reserve I/O memory, but in the error path when sci_remap_port() fails, it incorrectly calls release_resource() instead of release_mem_region(). This mismatch can cause resource accounting issues. Fix it by using the correct release function, consistent with sci_release_port(). Fixes: e2651647080930a1 ("serial: sh-sci: Handle port memory region reservations.") Cc: stable <stable@kernel.org> Reported-by: kernel test robot <lkp@intel.com> Reported-by: Dan Carpenter <error27@gmail.com> Closes: https://lore.kernel.org/r/202604032356.SzEjYkBC-lkp@intel.com/ Signed-off-by: Hongling Zeng <zenghongling@kylinos.cn> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Link: https://patch.msgid.link/20260421065737.724187-1-zenghongling@kylinos.cn Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-06-19tty: serial: pch_uart: add check for dma_alloc_coherent()Zhaoyang Yu1-6/+13
commit 6fe472c1bbbe238e91141f7cabc1226e96a60d43 upstream. Add a check for dma_alloc_coherent() failure to prevent a potential NULL pointer dereference in dma_handle_rx(). Properly release DMA channels and the PCI device reference using a goto ladder if the allocation fails. Fixes: 3c6a483275f4 ("Serial: EG20T: add PCH_UART driver") Cc: stable <stable@kernel.org> Signed-off-by: Zhaoyang Yu <2426767509@qq.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://patch.msgid.link/tencent_E328416B7CFD436F6029F2DF02AD7ED89C08@qq.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-06-01tty: hvc_iucv: fix off-by-one in number of supported devicesRandy Dunlap1-1/+1
[ Upstream commit f2a880e802ad12d1e38039d1334fb1475d0f5241 ] MAX_HVC_IUCV_LINES == HVC_ALLOC_TTY_ADAPTERS == 8. This is the number of entries in: static struct hvc_iucv_private *hvc_iucv_table[MAX_HVC_IUCV_LINES]; Sometimes hvc_iucv_table[] is limited by: (a) if (num > hvc_iucv_devices) // for error detection or (b) for (i = 0; i < hvc_iucv_devices; i++) // in 2 places (so these 2 don't agree; second one appears to be correct to me.) hvc_iucv_devices can be 0..8. This is a counter. (c) if (hvc_iucv_devices > MAX_HVC_IUCV_LINES) If hvc_iucv_devices == 8, (a) allows the code to access hvc_iucv_table[8]. Oops. Fixes: 44a01d5ba8a4 ("[S390] s390/hvc_console: z/VM IUCV hypervisor console support") Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Link: https://patch.msgid.link/20260130072939.1535869-1-rdunlap@infradead.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-06-01tty: hvc: remove HVC_IUCV_MAGICнаб1-6/+5
[ Upstream commit eef7381d8134f249dc17138bb1794c249aff7f5a ] According to Greg, in the context of magic numbers as defined in magic-number.rst, "the tty layer should not need this and I'll gladly take patches" This stretches that definition slightly, since it multiplexes it with the terminal number as a constant offset, but is equivalent Acked-by: Jiri Slaby <jirislaby@kernel.org> Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz> Ref: https://lore.kernel.org/linux-doc/YyMlovoskUcHLEb7@kroah.com/ Link: https://lore.kernel.org/r/8c8a2c9dfc1bfbe6ef3f3237368e483865fc1c29.1663288066.git.nabijaczleweli@nabijaczleweli.xyz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Stable-dep-of: f2a880e802ad ("tty: hvc_iucv: fix off-by-one in number of supported devices") Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-06-01tty: n_gsm: fix flow control handling in tx pathDaniel Starke1-1/+1
commit 59ff0680ecbfec742b1e0381e7cc46b41eb06647 upstream. The current implementation constipates all transmission paths during flow control except for flow control frames. However, these may not be located at the beginning of the transmission queue of the control channel. Ensure that flow control frames in the transmission queue for the control channel are always handled even if constipated by skipping through other messages. Fixes: 0af021678d5d ("tty: n_gsm: fix deadlock and link starvation in outgoing data path") Signed-off-by: Daniel Starke <daniel.starke@siemens.com> Link: https://lore.kernel.org/r/20220707113223.3685-3-daniel.starke@siemens.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-06-01tty: n_gsm: fix deadlock and link starvation in outgoing data pathDaniel Starke1-124/+279
[ Upstream commit 0af021678d5d30c31f5a6b631f404ead3575212a ] The current implementation queues up new control and user packets as needed and processes this queue down to the ldisc in the same code path. That means that the upper and the lower layer are hard coupled in the code. Due to this deadlocks can happen as seen below while transmitting data, especially during ldisc congestion. Furthermore, the data channels starve the control channel on high transmission load on the ldisc. Introduce an additional control channel data queue to prevent timeouts and link hangups during ldisc congestion. This is being processed before the user channel data queue in gsm_data_kick(), i.e. with the highest priority. Put the queue to ldisc data path into a workqueue and trigger it whenever new data has been put into the transmission queue. Change gsm_dlci_data_sweep() accordingly to fill up the transmission queue until TX_THRESH_HI. This solves the locking issue, keeps latency low and provides good performance on high data load. Note that now all packets from a DLCI are removed from the internal queue if the associated DLCI was closed. This ensures that no data is sent by the introduced write task to an already closed DLCI. BUG: spinlock recursion on CPU#0, test_v24_loop/124 lock: serial8250_ports+0x3a8/0x7500, .magic: dead4ead, .owner: test_v24_loop/124, .owner_cpu: 0 CPU: 0 PID: 124 Comm: test_v24_loop Tainted: G O 5.18.0-rc2 #3 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Call Trace: <IRQ> dump_stack_lvl+0x34/0x44 do_raw_spin_lock+0x76/0xa0 _raw_spin_lock_irqsave+0x72/0x80 uart_write_room+0x3b/0xc0 gsm_data_kick+0x14b/0x240 [n_gsm] gsmld_write_wakeup+0x35/0x70 [n_gsm] tty_wakeup+0x53/0x60 tty_port_default_wakeup+0x1b/0x30 serial8250_tx_chars+0x12f/0x220 serial8250_handle_irq.part.0+0xfe/0x150 serial8250_default_handle_irq+0x48/0x80 serial8250_interrupt+0x56/0xa0 __handle_irq_event_percpu+0x78/0x1f0 handle_irq_event+0x34/0x70 handle_fasteoi_irq+0x90/0x1e0 __common_interrupt+0x69/0x100 common_interrupt+0x48/0xc0 asm_common_interrupt+0x1e/0x40 RIP: 0010:__do_softirq+0x83/0x34e Code: 2a 0a ff 0f b7 ed c7 44 24 10 0a 00 00 00 48 c7 c7 51 2a 64 82 e8 2d e2 d5 ff 65 66 c7 05 83 af 1e 7e 00 00 fb b8 ff ff ff ff <49> c7 c2 40 61 80 82 0f bc c5 41 89 c4 41 83 c4 01 0f 84 e6 00 00 RSP: 0018:ffffc90000003f98 EFLAGS: 00000286 RAX: 00000000ffffffff RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff82642a51 RDI: ffffffff825bb5e7 RBP: 0000000000000200 R08: 00000008de3271a8 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000030 R14: 0000000000000000 R15: 0000000000000000 ? __do_softirq+0x73/0x34e irq_exit_rcu+0xb5/0x100 common_interrupt+0xa4/0xc0 </IRQ> <TASK> asm_common_interrupt+0x1e/0x40 RIP: 0010:_raw_spin_unlock_irqrestore+0x2e/0x50 Code: 00 55 48 89 fd 48 83 c7 18 53 48 89 f3 48 8b 74 24 10 e8 85 28 36 ff 48 89 ef e8 cd 58 36 ff 80 e7 02 74 01 fb bf 01 00 00 00 <e8> 3d 97 33 ff 65 8b 05 96 23 2b 7e 85 c0 74 03 5b 5d c3 0f 1f 44 RSP: 0018:ffffc9000020fd08 EFLAGS: 00000202 RAX: 0000000000000000 RBX: 0000000000000246 RCX: 0000000000000000 RDX: 0000000000000004 RSI: ffffffff8257fd74 RDI: 0000000000000001 RBP: ffff8880057de3a0 R08: 00000008de233000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000100 R14: 0000000000000202 R15: ffff8880057df0b8 ? _raw_spin_unlock_irqrestore+0x23/0x50 gsmtty_write+0x65/0x80 [n_gsm] n_tty_write+0x33f/0x530 ? swake_up_all+0xe0/0xe0 file_tty_write.constprop.0+0x1b1/0x320 ? n_tty_flush_buffer+0xb0/0xb0 new_sync_write+0x10c/0x190 vfs_write+0x282/0x310 ksys_write+0x68/0xe0 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f3e5e35c15c Code: 8b 7c 24 08 89 c5 e8 c5 ff ff ff 89 ef 89 44 24 08 e8 58 bc 02 00 8b 44 24 08 48 83 c4 10 5d c3 48 63 ff b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 10 48 8b 15 fd fc 05 00 f7 d8 64 89 02 48 83 RSP: 002b:00007ffcee77cd18 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007ffcee77cd70 RCX: 00007f3e5e35c15c RDX: 0000000000000100 RSI: 00007ffcee77cd90 RDI: 0000000000000003 RBP: 0000000000000100 R08: 0000000000000000 R09: 7efefefefefefeff R10: 00007f3e5e3bddeb R11: 0000000000000246 R12: 00007ffcee77ce8f R13: 0000000000000001 R14: 000056214404e010 R15: 00007ffcee77cd90 </TASK> Fixes: e1eaea46bb40 ("tty: n_gsm line discipline") Signed-off-by: Daniel Starke <daniel.starke@siemens.com> Link: https://lore.kernel.org/r/20220701122332.2039-1-daniel.starke@siemens.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [ The context change is due to the commit a8c5b8255f8a ("tty: n_gsm: fix broken virtual tty handling") in v5.18 which is irrelevant to the logic of this patch. ] Signed-off-by: Johnny Hao <johnny_haocn@sina.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-04-18serial: uartlite: fix PM runtime usage count underflow on probeMaciej Andrzejewski ICEYE1-0/+1
commit d54801cd509515f674a5aac1d3ea1401d2a05863 upstream. ulite_probe() calls pm_runtime_put_autosuspend() at the end of probe without holding a corresponding PM runtime reference for non-console ports. During ulite_assign(), uart_add_one_port() triggers uart_configure_port() which calls ulite_pm() via uart_change_pm(). For non-console ports, the UART core performs a balanced get/put cycle: uart_change_pm(ON) -> ulite_pm() -> pm_runtime_get_sync() +1 uart_change_pm(OFF) -> ulite_pm() -> pm_runtime_put_autosuspend() -1 This leaves no spare reference for the pm_runtime_put_autosuspend() at the end of probe. The PM runtime core prevents the count from actually going below zero, and instead triggers a "Runtime PM usage count underflow!" warning. For console ports the bug is masked: the UART core skips the uart_change_pm(OFF) call, so the UART core's unbalanced get happens to pair with probe's trailing put. Add pm_runtime_get_noresume() before pm_runtime_enable() to take an explicit probe-owned reference that the trailing pm_runtime_put_autosuspend() can release. This ensures a correct usage count regardless of whether the port is a console. Fixes: 5bbe10a6942d ("tty: serial: uartlite: Add runtime pm support") Cc: stable <stable@kernel.org> Signed-off-by: Maciej Andrzejewski ICEYE <maciej.andrzejewski@m-works.net> Link: https://patch.msgid.link/20260305123746.4152800-1-maciej.andrzejewski@m-works.net Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-04-18serial: 8250: Add late synchronize_irq() to shutdown to handle DW UART BUSYIlpo Järvinen1-0/+6
commit e0a368ae79531ff92105a2692f10d83052055856 upstream. When DW UART is !uart_16550_compatible, it can indicate BUSY at any point (when under constant Rx pressure) unless a complex sequence of steps is performed. Any LCR write can run a foul with the condition that prevents writing LCR while the UART is BUSY, which triggers BUSY_DETECT interrupt that seems unmaskable using IER bits. Normal flow is that dw8250_handle_irq() handles BUSY_DETECT condition by reading USR register. This BUSY feature, however, breaks the assumptions made in serial8250_do_shutdown(), which runs synchronize_irq() after clearing IER and assumes no interrupts can occur after that point but then proceeds to update LCR, which on DW UART can trigger an interrupt. If serial8250_do_shutdown() releases the interrupt handler before the handler has run and processed the BUSY_DETECT condition by read the USR register, the IRQ is not deasserted resulting in interrupt storm that triggers "irq x: nobody cared" warning leading to disabling the IRQ. Add late synchronize_irq() into serial8250_do_shutdown() to ensure BUSY_DETECT from DW UART is handled before port's interrupt handler is released. Alternative would be to add DW UART specific shutdown function but it would mostly duplicate the generic code and the extra synchronize_irq() seems pretty harmless in serial8250_do_shutdown(). Fixes: 7d4008ebb1c9 ("tty: add a DesignWare 8250 driver") Cc: stable <stable@kernel.org> Reported-by: Bandal, Shankar <shankar.bandal@intel.com> Tested-by: Bandal, Shankar <shankar.bandal@intel.com> Tested-by: Murthy, Shanth <shanth.murthy@intel.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://patch.msgid.link/20260203171049.4353-7-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-04-18serial: 8250: Fix TX deadlock when using DMARaul E Rangel1-0/+15
commit a424a34b8faddf97b5af41689087e7a230f79ba7 upstream. `dmaengine_terminate_async` does not guarantee that the `__dma_tx_complete` callback will run. The callback is currently the only place where `dma->tx_running` gets cleared. If the transaction is canceled and the callback never runs, then `dma->tx_running` will never get cleared and we will never schedule new TX DMA transactions again. This change makes it so we clear `dma->tx_running` after we terminate the DMA transaction. This is "safe" because `serial8250_tx_dma_flush` is holding the UART port lock. The first thing the callback does is also grab the UART port lock, so access to `dma->tx_running` is serialized. Fixes: 9e512eaaf8f4 ("serial: 8250: Fix fifo underflow on flush") Cc: stable <stable@kernel.org> Signed-off-by: Raul E Rangel <rrangel@google.com> Link: https://patch.msgid.link/20260209135815.1.I16366ecb0f62f3c96fe3dd5763fcf6f3c2b4d8cd@changeid Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-04-18serial: 8250_pci: add support for the AX99100Martin Roukala (né Peres)1-0/+17
commit 9c0072bc33d349c83d223e64be30794e11938a6b upstream. This is found in popular brands such as StarTech.com or Delock, and has been a source of frustration to quite a few people, if I can trust Amazon comments complaining about Linux support via the official out-of-the-tree driver. Signed-off-by: Martin Roukala (né Peres) <martin.roukala@mupuf.org> Cc: stable <stable@kernel.org> Link: https://patch.msgid.link/20260309-8250_pci_ax99100-v1-1-3328bdfd8e94@mupuf.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2026-03-04serial: 8250: 8250_omap.c: Clear DMA RX running status only after DMA ↵Moteen Shah1-1/+1
termination is done [ Upstream commit a5fd8945a478ff9be14812693891d7c9b4185a50 ] Clear rx_running flag only after DMA teardown polling completes. In the previous implementation the flag was being cleared while hardware teardown was still in progress, creating a mismatch between software state (flag = 0, "ready") and hardware state (still terminating). Signed-off-by: Moteen Shah <m-shah@ti.com> Link: https://patch.msgid.link/20260112081829.63049-3-m-shah@ti.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04serial: 8250_dw: handle clock enable errors in runtime_resumeArtem Shimko1-2/+9
[ Upstream commit d31228143a489ba6ba797896a07541ce06828c09 ] Add error checking for clk_prepare_enable() calls in dw8250_runtime_resume(). Currently if either clock fails to enable, the function returns success while leaving clocks in inconsistent state. This change implements comprehensive error handling by checking the return values of both clk_prepare_enable() calls. If the second clock enable operation fails after the first clock has already been successfully enabled, the code now properly cleans up by disabling and unpreparing the first clock before returning. The error code is then propagated to the caller, ensuring that clock enable failures are properly reported rather than being silently ignored. Signed-off-by: Artem Shimko <a.shimko.dev@gmail.com> Link: https://patch.msgid.link/20251104145433.2316165-2-a.shimko.dev@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04serial: SH_SCI: improve "DMA support" promptRandy Dunlap1-1/+1
[ Upstream commit 93bb95a11238d66a4c9aa6eabf9774b073a5895c ] Having a prompt of "DMA support" suddenly appear during a "make oldconfig" can be confusing. Add a little helpful text to the prompt message. Fixes: 73a19e4c0301 ("serial: sh-sci: Add DMA support.") Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> Link: https://patch.msgid.link/20260110232643.3533351-5-rdunlap@infradead.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-03-04serial: imx: change SERIAL_IMX_CONSOLE to boolRandy Dunlap1-3/+3
[ Upstream commit 79527d86ba91c2d9354832d19fd12b3baa66bd10 ] SERIAL_IMX_CONSOLE is a build option for the imx driver (SERIAL_IMX). It does not build a separate console driver file, so it can't be built as a module since it isn't built at all. Change the Kconfig symbol from tristate to bool and update the help text accordingly. Fixes: 0db4f9b91c86 ("tty: serial: imx: enable imx serial console port as module") Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Link: https://patch.msgid.link/20260110232643.3533351-2-rdunlap@infradead.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-01-19serial: sprd: Return -EPROBE_DEFER when uart clock is not readyWenhua Lin1-0/+6
[ Upstream commit 29e8a0c587e328ed458380a45d6028adf64d7487 ] In sprd_clk_init(), when devm_clk_get() returns -EPROBE_DEFER for either uart or source clock, we should propagate the error instead of just warning and continuing with NULL clocks. Currently the driver only emits a warning when clock acquisition fails and proceeds with NULL clock pointers. This can lead to issues later when the clocks are actually needed. More importantly, when the clock provider is not ready yet and returns -EPROBE_DEFER, we should return this error to allow deferred probing. This change adds explicit checks for -EPROBE_DEFER after both: 1. devm_clk_get(uport->dev, uart) 2. devm_clk_get(uport->dev, source) When -EPROBE_DEFER is encountered, the function now returns -EPROBE_DEFER to let the driver framework retry probing later when the clock dependencies are resolved. Signed-off-by: Wenhua Lin <Wenhua.Lin@unisoc.com> Link: https://patch.msgid.link/20251022030840.956589-1-Wenhua.Lin@unisoc.com Reviewed-by: Cixi Geng <cixi.geng@linux.dev> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2026-01-19serial: add support of CPCI cardsMagne Bruno1-0/+37
commit 0e5a99e0e5f50353b86939ff6e424800d769c818 upstream. Addi-Data GmbH is manufacturing multi-serial ports cards supporting CompactPCI (known as CPCI). Those cards are identified with different DeviceIds. Those cards integrating standard UARTs work the same way as PCI/PCIe models already supported in the serial driver. Signed-off-by: Magne Bruno <magne.bruno@addi-data.com> Link: https://patch.msgid.link/20251110162456.341029-1-magne.bruno@addi-data.com Cc: stable <stable@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-12-07serial: amba-pl011: prefer dma_mapping_error() over explicit address checkingMiaoqian Lin1-1/+1
commit eb4917f557d43c7a1c805dd73ffcdfddb2aba39a upstream. Check for returned DMA addresses using specialized dma_mapping_error() helper which is generally recommended for this purpose by Documentation/core-api/dma-api.rst: "In some circumstances dma_map_single(), ... will fail to create a mapping. A driver can check for these errors by testing the returned DMA address with dma_mapping_error()." Found via static analysis and this is similar to commit fa0308134d26 ("ALSA: memalloc: prefer dma_mapping_error() over explicit address checking") Fixes: 58ac1b379979 ("ARM: PL011: Fix DMA support") Cc: stable <stable@kernel.org> Signed-off-by: Miaoqian Lin <linmq006@gmail.com> Reviewed-by: Gregory CLEMENT <gregory.clement@bootlin.com> Link: https://patch.msgid.link/20251027092053.87937-1-linmq006@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-12-07serial: 8250_dw: handle reset control deassert errorArtem Shimko1-1/+3
[ Upstream commit daeb4037adf7d3349b4a1fb792f4bc9824686a4b ] Check the return value of reset_control_deassert() in the probe function to prevent continuing probe when reset deassertion fails. Previously, reset_control_deassert() was called without checking its return value, which could lead to probe continuing even when the device reset wasn't properly deasserted. The fix checks the return value and returns an error with dev_err_probe() if reset deassertion fails, providing better error handling and diagnostics. Fixes: acbdad8dd1ab ("serial: 8250_dw: simplify optional reset handling") Cc: stable <stable@kernel.org> Signed-off-by: Artem Shimko <a.shimko.dev@gmail.com> Link: https://patch.msgid.link/20251019095131.252848-1-a.shimko.dev@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>