kernel/linux.git/drivers/tty/serial/serial_core.c, branch v6.1.168

tty: introduce and use tty_port_tty_vhangup() helper

2026-01-11T14:19:23+00:00

[ Upstream commit 2b5eac0f8c6e79bc152c8804f9f88d16717013ab ] This code (tty_get -> vhangup -> tty_put) is repeated on few places. Introduce a helper similar to tty_port_tty_hangup() (asynchronous) to handle even vhangup (synchronous). And use it on those places. In fact, reuse the tty_port_tty_hangup()'s code and call tty_vhangup() depending on a new bool parameter. Signed-off-by: "Jiri Slaby (SUSE)" Cc: Karsten Keil Cc: David Lin Cc: Johan Hovold Cc: Alex Elder Cc: Oliver Neukum Cc: Marcel Holtmann Cc: Johan Hedberg Cc: Luiz Augusto von Dentz Reviewed-by: Ilpo Järvinen Link: https://lore.kernel.org/r/20250611100319.186924-2-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman Stable-dep-of: 74098cc06e75 ("xhci: dbgtty: fix device unregister: fixup") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

serial: Make uart_remove_one_port() return void

2026-01-11T14:19:23+00:00

[ Upstream commit d5b3d02d0b107345f2a6ecb5b06f98356f5c97ab ] The return value is only ever used as a return value for remove callbacks of platform drivers. This return value is ignored by the driver core. (The only effect is an error message, but uart_remove_one_port() already emitted one in this case.) So the return value isn't used at all and uart_remove_one_port() can be changed to return void without any loss. Also this better matches the Linux device model as remove functions are not supposed to fail. Signed-off-by: Uwe Kleine-König Link: https://lore.kernel.org/r/20230512173810.131447-3-u.kleine-koenig@pengutronix.de Signed-off-by: Greg Kroah-Hartman Stable-dep-of: 74098cc06e75 ("xhci: dbgtty: fix device unregister: fixup") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

serial: protect uart_port_dtr_rts() in uart_shutdown() too

2024-11-01T00:56:07+00:00

[ Upstream commit 602babaa84d627923713acaf5f7e9a4369e77473 ] Commit af224ca2df29 (serial: core: Prevent unsafe uart port access, part 3) added few uport == NULL checks. It added one to uart_shutdown(), so the commit assumes, uport can be NULL in there. But right after that protection, there is an unprotected "uart_port_dtr_rts(uport, false);" call. That is invoked only if HUPCL is set, so I assume that is the reason why we do not see lots of these reports. Or it cannot be NULL at this point at all for some reason :P. Until the above is investigated, stay on the safe side and move this dereference to the if too. I got this inconsistency from Coverity under CID 1585130. Thanks. Signed-off-by: Jiri Slaby (SUSE) Cc: Peter Hurley Cc: Greg Kroah-Hartman Link: https://lore.kernel.org/r/20240805102046.307511-3-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman [Adapted over commit 5701cb8bf50e ("tty: Call ->dtr_rts() parameter active consistently") not in the tree] Signed-off-by: Tomas Krcka Signed-off-by: Sasha Levin

serial: Make uart_handle_cts_change() status param bool active

2024-11-01T00:56:02+00:00

[ Upstream commit 968d64578ec92968e8c79d766eb966efd1f68d7e ] Convert uart_handle_cts_change() to bool which is more appropriate than unsigned int. Rename status to active to better describe what the parameter means. While at it, make the comment about the active parameter easier to parse. Cleanup callsites from operations that are not necessary with bool. Reviewed-by: Jiri Slaby Signed-off-by: Ilpo Järvinen Link: https://lore.kernel.org/r/20230117090358.4796-10-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman Stable-dep-of: 40d7903386df ("serial: imx: Update mctrl old_status on RTSD interrupt") Signed-off-by: Sasha Levin

tty/serial: Make ->dcd_change()+uart_handle_dcd_change() status bool active

2024-11-01T00:56:02+00:00

[ Upstream commit 0388a152fc5544be82e736343496f99c4eef8d62 ] Convert status parameter for ->dcd_change() and uart_handle_dcd_change() to bool which matches to how the parameter is used. Rename status to active to better describe what the parameter means. Acked-by: Rodolfo Giometti Reviewed-by: Jiri Slaby Signed-off-by: Ilpo Järvinen Link: https://lore.kernel.org/r/20230117090358.4796-9-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman Stable-dep-of: 40d7903386df ("serial: imx: Update mctrl old_status on RTSD interrupt") Signed-off-by: Sasha Levin

serial: core: check uartclk for zero to avoid divide by zero

2024-08-14T11:52:58+00:00

commit 6eabce6608d6f3440f4c03aa3d3ef50a47a3d193 upstream. Calling ioctl TIOCSSERIAL with an invalid baud_base can result in uartclk being zero, which will result in a divide by zero error in uart_get_divisor(). The check for uartclk being zero in uart_set_info() needs to be done before other settings are made as subsequent calls to ioctl TIOCSSERIAL for the same port would be impacted if the uartclk check was done where uartclk gets set. Oops: divide error: 0000 PREEMPT SMP KASAN PTI RIP: 0010:uart_get_divisor (drivers/tty/serial/serial_core.c:580) Call Trace: serial8250_get_divisor (drivers/tty/serial/8250/8250_port.c:2576 drivers/tty/serial/8250/8250_port.c:2589) serial8250_do_set_termios (drivers/tty/serial/8250/8250_port.c:502 drivers/tty/serial/8250/8250_port.c:2741) serial8250_set_termios (drivers/tty/serial/8250/8250_port.c:2862) uart_change_line_settings (./include/linux/spinlock.h:376 ./include/linux/serial_core.h:608 drivers/tty/serial/serial_core.c:222) uart_port_startup (drivers/tty/serial/serial_core.c:342) uart_startup (drivers/tty/serial/serial_core.c:368) uart_set_info (drivers/tty/serial/serial_core.c:1034) uart_set_info_user (drivers/tty/serial/serial_core.c:1059) tty_set_serial (drivers/tty/tty_io.c:2637) tty_ioctl (drivers/tty/tty_io.c:2647 drivers/tty/tty_io.c:2791) __x64_sys_ioctl (fs/ioctl.c:52 fs/ioctl.c:907 fs/ioctl.c:893 fs/ioctl.c:893) do_syscall_64 (arch/x86/entry/common.c:52 (discriminator 1) arch/x86/entry/common.c:83 (discriminator 1)) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130) Reported-by: syzkaller Cc: stable@vger.kernel.org Signed-off-by: George Kennedy Rule: add Link: https://lore.kernel.org/stable/1721148848-9784-1-git-send-email-george.kennedy%40oracle.com Link: https://lore.kernel.org/r/1721219078-3209-1-git-send-email-george.kennedy@oracle.com Signed-off-by: Greg Kroah-Hartman

serial: Lock console when calling into driver before registration

2024-04-03T13:19:31+00:00

[ Upstream commit 801410b26a0e8b8a16f7915b2b55c9528b69ca87 ] During the handoff from earlycon to the real console driver, we have two separate drivers operating on the same device concurrently. In the case of the 8250 driver these concurrent accesses cause problems due to the driver's use of banked registers, controlled by LCR.DLAB. It is possible for the setup(), config_port(), pm() and set_mctrl() callbacks to set DLAB, which can cause the earlycon code that intends to access TX to instead access DLL, leading to missed output and corruption on the serial line due to unintended modifications to the baud rate. In particular, for setup() we have: univ8250_console_setup() -> serial8250_console_setup() -> uart_set_options() -> serial8250_set_termios() -> serial8250_do_set_termios() -> serial8250_do_set_divisor() For config_port() we have: serial8250_config_port() -> autoconfig() For pm() we have: serial8250_pm() -> serial8250_do_pm() -> serial8250_set_sleep() For set_mctrl() we have (for some devices): serial8250_set_mctrl() -> omap8250_set_mctrl() -> __omap8250_set_mctrl() To avoid such problems, let's make it so that the console is locked during pre-registration calls to these callbacks, which will prevent the earlycon driver from running concurrently. Remove the partial solution to this problem in the 8250 driver that locked the console only during autoconfig_irq(), as this would result in a deadlock with the new approach. The console continues to be locked during autoconfig_irq() because it can only be called through uart_configure_port(). Although this patch introduces more locking than strictly necessary (and in particular it also locks during the call to rs485_config() which is not affected by this issue as far as I can tell), it follows the principle that it is the responsibility of the generic console code to manage the earlycon handoff by ensuring that earlycon and real console driver code cannot run concurrently, and not the individual drivers. Signed-off-by: Peter Collingbourne Reviewed-by: John Ogness Link: https://linux-review.googlesource.com/id/I7cf8124dcebf8618e6b2ee543fa5b25532de55d8 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20240304214350.501253-1-pcc@google.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

serial: core, imx: do not set RS485 enabled if it is not supported

2024-01-25T23:27:40+00:00

commit 74eab89b26ac433ad857292f4707b43c1a8f0209 upstream. If the imx driver cannot support RS485 it nullifies the ports rs485_supported structure. But it still calls uart_get_rs485_mode() which may set the RS485_ENABLED flag nevertheless. This may lead to an attempt to configure RS485 even if it is not supported when the flag is evaluated in uart_configure_port() at port startup. Avoid this by bailing out of uart_get_rs485_mode() if the RS485_ENABLED flag is not supported by the caller. With this fix a check for RTS availability is now obsolete in the imx driver, since it can not evaluate to true any more. So remove this check. Furthermore the explicit nullifcation of rs485_supported is not needed, since the memory has already been set to zeros at allocation. So remove this, too. Fixes: 00d7a00e2a6f ("serial: imx: Fill in rs485_supported") Cc: Shawn Guo Cc: Sascha Hauer Cc: Suggested-by: Uwe Kleine-König Signed-off-by: Lino Sanfilippo Reviewed-by: Ilpo Järvinen Link: https://lore.kernel.org/r/20240103061818.564-6-l.sanfilippo@kunbus.com Signed-off-by: Greg Kroah-Hartman

serial: core: make sure RS485 cannot be enabled when it is not supported

2024-01-25T23:27:40+00:00

commit c73986913fa47e71e0b1ad7f039f6444915e8810 upstream. Some uart drivers specify a rs485_config() function and then decide later to disable RS485 support for some reason (e.g. imx and ar933). In these cases userspace may be able to activate RS485 via TIOCSRS485 nevertheless, since in uart_set_rs485_config() an existing rs485_config() function indicates that RS485 is supported. Make sure that this is not longer possible by checking the uarts rs485_supported.flags instead and bailing out if SER_RS485_ENABLED is not set. Furthermore instead of returning an empty structure return -ENOTTY if the RS485 configuration is requested via TIOCGRS485 but RS485 is not supported. This has a small impact on userspace visibility but it is consistent with the -ENOTTY error for TIOCGRS485. Fixes: e849145e1fdd ("serial: ar933x: Fill in rs485_supported") Fixes: 55e18c6b6d42 ("serial: imx: Remove serial_rs485 sanitization") Cc: Shawn Guo Cc: Sascha Hauer Cc: Reviewed-by: Ilpo Järvinen Signed-off-by: Lino Sanfilippo Link: https://lore.kernel.org/r/20240103061818.564-5-l.sanfilippo@kunbus.com Signed-off-by: Greg Kroah-Hartman

serial: core: fix sanitizing check for RTS settings

2024-01-25T23:27:40+00:00

commit 4afeced55baa391490b61ed9164867e2927353ed upstream. Among other things uart_sanitize_serial_rs485() tests the sanity of the RTS settings in a RS485 configuration that has been passed by userspace. If RTS-on-send and RTS-after-send are both set or unset the configuration is adjusted and RTS-after-send is disabled and RTS-on-send enabled. This however makes only sense if both RTS modes are actually supported by the driver. With commit be2e2cb1d281 ("serial: Sanitize rs485_struct") the code does take the driver support into account but only checks if one of both RTS modes are supported. This may lead to the errorneous result of RTS-on-send being set even if only RTS-after-send is supported. Fix this by changing the implemented logic: First clear all unsupported flags in the RS485 configuration, then adjust an invalid RTS setting by taking into account which RTS mode is supported. Cc: Fixes: be2e2cb1d281 ("serial: Sanitize rs485_struct") Reviewed-by: Ilpo Järvinen Signed-off-by: Lino Sanfilippo Link: https://lore.kernel.org/r/20240103061818.564-4-l.sanfilippo@kunbus.com Signed-off-by: Greg Kroah-Hartman