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2021-12-20Merge branch 'xsa' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tipLinus Torvalds
Merge xen fixes from Juergen Gross: "Fixes for two issues related to Xen and malicious guests: - Guest can force the netback driver to hog large amounts of memory - Denial of Service in other guests due to event storms" * 'xsa' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: xen/netback: don't queue unlimited number of packages xen/netback: fix rx queue stall detection xen/console: harden hvc_xen against event channel storms xen/netfront: harden netfront against event channel storms xen/blkfront: harden blkfront against event channel storms
2021-12-16xen/console: harden hvc_xen against event channel stormsJuergen Gross
The Xen console driver is still vulnerable for an attack via excessive number of events sent by the backend. Fix that by using a lateeoi event channel. For the normal domU initial console this requires the introduction of bind_evtchn_to_irq_lateeoi() as there is no xenbus device available at the time the event channel is bound to the irq. As the decision whether an interrupt was spurious or not requires to test for bytes having been read from the backend, move sending the event into the if statement, as sending an event without having found any bytes to be read is making no sense at all. This is part of XSA-391 Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> --- V2: - slightly adapt spurious irq detection (Jan Beulich) V3: - fix spurious irq detection (Jan Beulich)
2021-12-15serial: 8250_fintek: Fix garbled text for consoleJi-Ze Hong (Peter Hong)
Commit fab8a02b73eb ("serial: 8250_fintek: Enable high speed mode on Fintek F81866") introduced support to use high baudrate with Fintek SuperIO UARTs. It'll change clocksources when the UART probed. But when user add kernel parameter "console=ttyS0,115200 console=tty0" to make the UART as console output, the console will output garbled text after the following kernel message. [ 3.681188] Serial: 8250/16550 driver, 32 ports, IRQ sharing enabled The issue is occurs in following step: probe_setup_port() -> fintek_8250_goto_highspeed() It change clocksource from 115200 to 921600 with wrong time, it should change clocksource in set_termios() not in probed. The following 3 patches are implemented change clocksource in fintek_8250_set_termios(). Commit 58178914ae5b ("serial: 8250_fintek: UART dynamic clocksource on Fintek F81216H") Commit 195638b6d44f ("serial: 8250_fintek: UART dynamic clocksource on Fintek F81866") Commit 423d9118c624 ("serial: 8250_fintek: Add F81966 Support") Due to the high baud rate had implemented above 3 patches and the patch Commit fab8a02b73eb ("serial: 8250_fintek: Enable high speed mode on Fintek F81866") is bugged, So this patch will remove it. Fixes: fab8a02b73eb ("serial: 8250_fintek: Enable high speed mode on Fintek F81866") Signed-off-by: Ji-Ze Hong (Peter Hong) <hpeter+linux_kernel@gmail.com> Link: https://lore.kernel.org/r/20211215075835.2072-1-hpeter+linux_kernel@gmail.com Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-12-15tty: n_hdlc: make n_hdlc_tty_wakeup() asynchronousTetsuo Handa
syzbot is reporting that an unprivileged user who logged in from tty console can crash the system using a reproducer shown below [1], for n_hdlc_tty_wakeup() is synchronously calling n_hdlc_send_frames(). ---------- #include <sys/ioctl.h> #include <unistd.h> int main(int argc, char *argv[]) { const int disc = 0xd; ioctl(1, TIOCSETD, &disc); while (1) { ioctl(1, TCXONC, 0); write(1, "", 1); ioctl(1, TCXONC, 1); /* Kernel panic - not syncing: scheduling while atomic */ } } ---------- Linus suspected that "struct tty_ldisc"->ops->write_wakeup() must not sleep, and Jiri confirmed it from include/linux/tty_ldisc.h. Thus, defer n_hdlc_send_frames() from n_hdlc_tty_wakeup() to a WQ context like net/nfc/nci/uart.c does. Link: https://syzkaller.appspot.com/bug?extid=5f47a8cea6a12b77a876 [1] Reported-by: syzbot <syzbot+5f47a8cea6a12b77a876@syzkaller.appspotmail.com> Cc: stable <stable@vger.kernel.org> Analyzed-by: Fabio M. De Francesco <fmdefrancesco@gmail.com> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Confirmed-by: Jiri Slaby <jirislaby@kernel.org> Reviewed-by: Fabio M. De Francesco <fmdefrancesco@gmail.com> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Link: https://lore.kernel.org/r/40de8b7e-a3be-4486-4e33-1b1d1da452f8@i-love.sakura.ne.jp Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-12-05Merge tag 'tty-5.16-rc4' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty Pull tty/serial fixes from Greg KH: "Here are some small TTY and Serial driver fixes for 5.16-rc4 to resolve a number of reported problems. They include: - liteuart serial driver fixes - 8250_pci serial driver fixes for pericom devices - 8250 RTS line control fix while in RS-485 mode - tegra serial driver fix - msm_serial driver fix - pl011 serial driver new id - fsl_lpuart revert of broken change - 8250_bcm7271 serial driver fix - MAINTAINERS file update for rpmsg tty driver that came in 5.16-rc1 - vgacon fix for reported problem All of these, except for the 8250_bcm7271 fix have been in linux-next with no reported problem. The 8250_bcm7271 fix was added to the tree on Friday so no chance to be linux-next yet. But it should be fine as the affected developers submitted it" * tag 'tty-5.16-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: serial: 8250_bcm7271: UART errors after resuming from S2 serial: 8250_pci: rewrite pericom_do_set_divisor() serial: 8250_pci: Fix ACCES entries in pci_serial_quirks array serial: 8250: Fix RTS modem control while in rs485 mode Revert "tty: serial: fsl_lpuart: drop earlycon entry for i.MX8QXP" serial: tegra: Change lower tolerance baud rate limit for tegra20 and tegra30 serial: liteuart: relax compile-test dependencies serial: liteuart: fix minor-number leak on probe errors serial: liteuart: fix use-after-free and memleak on unbind serial: liteuart: Fix NULL pointer dereference in ->remove() vgacon: Propagate console boot parameters before calling `vc_resize' tty: serial: msm_serial: Deactivate RX DMA for polling support serial: pl011: Add ACPI SBSA UART match id serial: core: fix transmit-buffer reset and memleak MAINTAINERS: Add rpmsg tty driver maintainer
2021-12-03serial: 8250_bcm7271: UART errors after resuming from S2Al Cooper
There is a small window in time during resume where the hardware flow control signal RTS can be asserted (which allows a sender to resume sending data to the UART) but the baud rate has not yet been restored. This will cause corrupted data and FRAMING, OVERRUN and BREAK errors. This is happening because the MCTRL register is shadowed in uart_port struct and is later used during resume to set the MCTRL register during both serial8250_do_startup() and uart_resume_port(). Unfortunately, serial8250_do_startup() happens before the UART baud rate is restored. The fix is to clear the shadowed mctrl value at the end of suspend and restore it at the end of resume. Fixes: 41a469482de2 ("serial: 8250: Add new 8250-core based Broadcom STB driver") Acked-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: Al Cooper <alcooperx@gmail.com> Link: https://lore.kernel.org/r/20211201201402.47446-1-alcooperx@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-25serial: 8250_pci: rewrite pericom_do_set_divisor()Jay Dolan
Have pericom_do_set_divisor() use the uartclk instead of a hard coded value to work with different speed crystals. Tested with 14.7456 and 24 MHz crystals. Have pericom_do_set_divisor() always calculate the divisor rather than call serial8250_do_set_divisor() for rates below baud_base. Do not write registers or call serial8250_do_set_divisor() if valid divisors could not be found. Fixes: 6bf4e42f1d19 ("serial: 8250: Add support for higher baud rates to Pericom chips") Cc: stable <stable@vger.kernel.org> Signed-off-by: Jay Dolan <jay.dolan@accesio.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20211122120604.3909-3-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-25serial: 8250_pci: Fix ACCES entries in pci_serial_quirks arrayJay Dolan
Fix error in table for PCI_DEVICE_ID_ACCESIO_PCIE_ICM_4S that caused it and PCI_DEVICE_ID_ACCESIO_PCIE_ICM232_4 to be missing their fourth port. Fixes: 78d3820b9bd3 ("serial: 8250_pci: Have ACCES cards that use the four port Pericom PI7C9X7954 chip use the pci_pericom_setup()") Cc: stable <stable@vger.kernel.org> Signed-off-by: Jay Dolan <jay.dolan@accesio.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20211122120604.3909-2-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-25serial: 8250: Fix RTS modem control while in rs485 modeLukas Wunner
Commit f45709df7731 ("serial: 8250: Don't touch RTS modem control while in rs485 mode") sought to prevent user space from interfering with rs485 communication by ignoring a TIOCMSET ioctl() which changes RTS polarity. It did so in serial8250_do_set_mctrl(), which turns out to be too deep in the call stack: When a uart_port is opened, RTS polarity is set by the rs485-aware function uart_port_dtr_rts(). It calls down to serial8250_do_set_mctrl() and that particular RTS polarity change should *not* be ignored. The user-visible result is that on 8250_omap ports which use rs485 with inverse polarity (RTS bit in MCR register is 1 to receive, 0 to send), a newly opened port initially sets up RTS for sending instead of receiving. That's because omap_8250_startup() sets the cached value up->mcr to 0 and omap_8250_restore_regs() subsequently writes it to the MCR register. Due to the commit, serial8250_do_set_mctrl() preserves that incorrect register value: do_sys_openat2 do_filp_open path_openat vfs_open do_dentry_open chrdev_open tty_open uart_open tty_port_open uart_port_activate uart_startup uart_port_startup serial8250_startup omap_8250_startup # up->mcr = 0 uart_change_speed serial8250_set_termios omap_8250_set_termios omap_8250_restore_regs serial8250_out_MCR # up->mcr written tty_port_block_til_ready uart_dtr_rts uart_port_dtr_rts serial8250_set_mctrl omap8250_set_mctrl serial8250_do_set_mctrl # mcr[1] = 1 ignored Fix by intercepting RTS changes from user space in uart_tiocmset() instead. Link: https://lore.kernel.org/linux-serial/20211027111644.1996921-1-baocheng.su@siemens.com/ Fixes: f45709df7731 ("serial: 8250: Don't touch RTS modem control while in rs485 mode") Cc: Chao Zeng <chao.zeng@siemens.com> Cc: stable@vger.kernel.org # v5.7+ Reported-by: Su Bao Cheng <baocheng.su@siemens.com> Reported-by: Jan Kiszka <jan.kiszka@siemens.com> Tested-by: Su Bao Cheng <baocheng.su@siemens.com> Signed-off-by: Lukas Wunner <lukas@wunner.de> Link: https://lore.kernel.org/r/21170e622a1aaf842a50b32146008b5374b3dd1d.1637596432.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-25Revert "tty: serial: fsl_lpuart: drop earlycon entry for i.MX8QXP"Alexander Stein
Revert commit b4b844930f27 ("tty: serial: fsl_lpuart: drop earlycon entry for i.MX8QXP"), because this breaks earlycon support on imx8qm/imx8qxp. While it is true that for earlycon there is no difference between i.MX8QXP and i.MX7ULP (for now at least), there are differences regarding clocks and fixups for wakeup support. For that reason it was deemed unacceptable to add the imx7ulp compatible to device tree in order to get earlycon working again. Reviewed-by: Peng Fan <peng.fan@nxp.com> Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com> Link: https://lore.kernel.org/r/20211124073109.805088-1-alexander.stein@ew.tq-group.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-25serial: tegra: Change lower tolerance baud rate limit for tegra20 and tegra30Patrik John
The current implementation uses 0 as lower limit for the baud rate tolerance for tegra20 and tegra30 chips which causes isses on UART initialization as soon as baud rate clock is lower than required even when within the standard UART tolerance of +/- 4%. This fix aligns the implementation with the initial commit description of +/- 4% tolerance for tegra chips other than tegra186 and tegra194. Fixes: d781ec21bae6 ("serial: tegra: report clk rate errors") Cc: stable <stable@vger.kernel.org> Signed-off-by: Patrik John <patrik.john@u-blox.com> Link: https://lore.kernel.org/r/sig.19614244f8.20211123132737.88341-1-patrik.john@u-blox.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-25serial: liteuart: relax compile-test dependenciesJohan Hovold
The LITEX symbol is neither a build or runtime dependency for the liteuart serial driver. LITEX is selected by the "LiteX SoC Controller" driver, which does a probe-time register-access sanity check and panics if the SoC has not been configured correctly. That driver's Kconfig entry asserts that any LiteX driver using the LiteX register accessors should depend on LITEX, but currently only the serial driver complies. Relax this LITEX "dependency" in order to make it easier to compile test the driver. Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Johan Hovold <johan@kernel.org> Link: https://lore.kernel.org/r/20211117100512.5058-4-johan@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-25serial: liteuart: fix minor-number leak on probe errorsJohan Hovold
Make sure to release the allocated minor number before returning on probe errors. Fixes: 1da81e5562fa ("drivers/tty/serial: add LiteUART driver") Cc: stable@vger.kernel.org # 5.11 Cc: Filip Kokosinski <fkokosinski@antmicro.com> Cc: Mateusz Holenko <mholenko@antmicro.com> Reviewed-by: Stafford Horne <shorne@gmail.com> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Johan Hovold <johan@kernel.org> Link: https://lore.kernel.org/r/20211117100512.5058-3-johan@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-25serial: liteuart: fix use-after-free and memleak on unbindJohan Hovold
Deregister the port when unbinding the driver to prevent it from being used after releasing the driver data and leaking memory allocated by serial core. Fixes: 1da81e5562fa ("drivers/tty/serial: add LiteUART driver") Cc: stable@vger.kernel.org # 5.11 Cc: Filip Kokosinski <fkokosinski@antmicro.com> Cc: Mateusz Holenko <mholenko@antmicro.com> Reviewed-by: Stafford Horne <shorne@gmail.com> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Johan Hovold <johan@kernel.org> Link: https://lore.kernel.org/r/20211117100512.5058-2-johan@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-25serial: liteuart: Fix NULL pointer dereference in ->remove()Ilia Sergachev
drvdata has to be set in _probe() - otherwise platform_get_drvdata() causes null pointer dereference BUG in _remove(). Fixes: 1da81e5562fa ("drivers/tty/serial: add LiteUART driver") Cc: stable <stable@vger.kernel.org> Reviewed-by: Johan Hovold <johan@kernel.org> Signed-off-by: Ilia Sergachev <silia@ethz.ch> Link: https://lore.kernel.org/r/20211115224944.23f8c12b@dtkw Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-25tty: serial: msm_serial: Deactivate RX DMA for polling supportSven Eckelmann
The CONSOLE_POLLING mode is used for tools like k(g)db. In this kind of setup, it is often sharing a serial device with the normal system console. This is usually no problem because the polling helpers can consume input values directly (when in kgdb context) and the normal Linux handlers can only consume new input values after kgdb switched back. This is not true anymore when RX DMA is enabled for UARTDM controllers. Single input values can no longer be received correctly. Instead following seems to happen: * on 1. input, some old input is read (continuously) * on 2. input, two old inputs are read (continuously) * on 3. input, three old input values are read (continuously) * on 4. input, 4 previous inputs are received This repeats then for each group of 4 input values. This behavior changes slightly depending on what state the controller was when the first input was received. But this makes working with kgdb basically impossible because control messages are always corrupted when kgdboc tries to parse them. RX DMA should therefore be off when CONSOLE_POLLING is enabled to avoid these kind of problems. No such problem was noticed for TX DMA. Fixes: 99693945013a ("tty: serial: msm: Add RX DMA support") Cc: stable@vger.kernel.org Signed-off-by: Sven Eckelmann <sven@narfation.org> Link: https://lore.kernel.org/r/20211113121050.7266-1-sven@narfation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-25serial: pl011: Add ACPI SBSA UART match idPierre Gondois
The document 'ACPI for Arm Components 1.0' defines the following _HID mappings: -'Prime cell UART (PL011)': ARMH0011 -'SBSA UART': ARMHB000 Use the sbsa-uart driver when a device is described with the 'ARMHB000' _HID. Note: PL011 devices currently use the sbsa-uart driver instead of the uart-pl011 driver. Indeed, PL011 devices are not bound to a clock in ACPI. It is not possible to change their baudrate. Cc: <stable@vger.kernel.org> Signed-off-by: Pierre Gondois <Pierre.Gondois@arm.com> Link: https://lore.kernel.org/r/20211109172248.19061-1-Pierre.Gondois@arm.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-25serial: core: fix transmit-buffer reset and memleakJohan Hovold
Commit 761ed4a94582 ("tty: serial_core: convert uart_close to use tty_port_close") converted serial core to use tty_port_close() but failed to notice that the transmit buffer still needs to be freed on final close. Not freeing the transmit buffer means that the buffer is no longer cleared on next open so that any ioctl() waiting for the buffer to drain might wait indefinitely (e.g. on termios changes) or that stale data can end up being transmitted in case tx is restarted. Furthermore, the buffer of any port that has been opened would leak on driver unbind. Note that the port lock is held when clearing the buffer pointer due to the ldisc race worked around by commit a5ba1d95e46e ("uart: fix race between uart_put_char() and uart_shutdown()"). Also note that the tty-port shutdown() callback is not called for console ports so it is not strictly necessary to free the buffer page after releasing the lock (cf. d72402145ace ("tty/serial: do not free trasnmit buffer page under port lock")). Link: https://lore.kernel.org/r/319321886d97c456203d5c6a576a5480d07c3478.1635781688.git.baruch@tkos.co.il Fixes: 761ed4a94582 ("tty: serial_core: convert uart_close to use tty_port_close") Cc: stable@vger.kernel.org # 4.9 Cc: Rob Herring <robh@kernel.org> Reported-by: Baruch Siach <baruch@tkos.co.il> Tested-by: Baruch Siach <baruch@tkos.co.il> Signed-off-by: Johan Hovold <johan@kernel.org> Link: https://lore.kernel.org/r/20211108085431.12637-1-johan@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-23xen: flag hvc_xen to be not essential for system bootJuergen Gross
The Xen pv console driver is not essential for boot. Set the respective flag. Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Link: https://lore.kernel.org/r/20211022064800.14978-4-jgross@suse.com Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
2021-11-04Merge tag 'tty-5.16-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty Pull tty / serial driver updates from Greg KH: "Here is the big set of tty and serial driver updates for 5.16-rc1. Nothing major in here at all, just lots of tiny serial and tty driver updates for various reported things, and some good cleanups. These include: - more good tty api cleanups from Jiri - stm32 serial driver updates - softlockup fix for non-preempt systems under high serial load - rpmsg serial driver update - 8250 drivers updates and fixes - n_gsm line discipline fixes and updates as people are finally starting to use it. All of these have been in linux-next for a while now with no reported issues" * tag 'tty-5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (86 commits) tty: Fix extra "not" in TTY_DRIVER_REAL_RAW description serial: cpm_uart: Protect udbg definitions by CONFIG_SERIAL_CPM_CONSOLE tty: rpmsg: Define tty name via constant string literal tty: rpmsg: Add pr_fmt() to prefix messages tty: rpmsg: Use dev_err_probe() in ->probe() tty: rpmsg: Unify variable used to keep an error code tty: rpmsg: Assign returned id to a local variable serial: stm32: push DMA RX data before suspending serial: stm32: terminate / restart DMA transfer at suspend / resume serial: stm32: rework RX dma initialization and release serial: 8250_pci: Remove empty stub pci_quatech_exit() serial: 8250_pci: Replace custom pci_match_id() implementation serial: xilinx_uartps: Fix race condition causing stuck TX serial: sunzilog: Mark sunzilog_putchar() __maybe_unused Revert "tty: hvc: pass DMA capable memory to put_chars()" Revert "virtio-console: remove unnecessary kmemdup()" serial: 8250_pci: Replace dev_*() by pci_*() macros serial: 8250_pci: Get rid of redundant 'else' keyword serial: 8250_pci: Refactor the loop in pci_ite887x_init() tty: add rpmsg driver ...
2021-10-30serial: cpm_uart: Protect udbg definitions by CONFIG_SERIAL_CPM_CONSOLEGeert Uytterhoeven
If CONFIG_CONSOLE_POLL=y, and CONFIG_SERIAL_CPM=m (hence CONFIG_SERIAL_CPM_CONSOLE=n): drivers/tty/serial/cpm_uart/cpm_uart_core.c:1109:12: warning: ‘udbg_cpm_getc’ defined but not used [-Wunused-function] 1109 | static int udbg_cpm_getc(void) | ^~~~~~~~~~~~~ drivers/tty/serial/cpm_uart/cpm_uart_core.c:1095:13: warning: ‘udbg_cpm_putc’ defined but not used [-Wunused-function] 1095 | static void udbg_cpm_putc(char c) | ^~~~~~~~~~~~~ Fix this by making the udbg definitions depend on CONFIG_SERIAL_CPM_CONSOLE, in addition to CONFIG_CONSOLE_POLL. Fixes: a60526097f42eb98 ("tty: serial: cpm_uart: Add udbg support for enabling xmon") Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Link: https://lore.kernel.org/r/20211027075326.3270785-1-geert@linux-m68k.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-26tty: rpmsg: Define tty name via constant string literalAndy Shevchenko
Driver uses already twice the same string literal. Define it in one place, so every user will have this name consistent. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20211025135148.53944-5-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-26tty: rpmsg: Add pr_fmt() to prefix messagesAndy Shevchenko
Make all messages to be prefixed in a unified way. Add pr_fmt() to achieve this. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20211025135148.53944-4-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-26tty: rpmsg: Use dev_err_probe() in ->probe()Andy Shevchenko
It's fine to use dev_err_probe() in ->probe() even if we know it won't be deferred. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20211025135148.53944-3-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-26tty: rpmsg: Unify variable used to keep an error codeAndy Shevchenko
In some ret is used, in the other err. Let's unify it across the driver. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20211025135148.53944-2-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-26tty: rpmsg: Assign returned id to a local variableAndy Shevchenko
Instead of putting garbage in the data structure, assign allocated id or an error code to a temporary variable. This makes code cleaner. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20211025135148.53944-1-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-26serial: stm32: push DMA RX data before suspendingErwan Le Ray
Data may be stored in DMA RX buffer, when suspending. The data needs to be pushed to the upper layer. We can't rely on the timeout IRQ (RTOR) that can't be triggered into low power state. So safely clear DMA request (DMAR), force the DMA reception routines to push RX buffer content, before disabling RX DMA. This way, handover to pio mode is safe. Only call tty_flip_buffer_push() when there is RX data to handle. Move the locking outside of stm32_usart_receive_chars() to prevent a race condition, when disabling DMA request upon suspend / pm_runtime_suspend. Data may be received under IRQ and pushed before stm32_usart_receive_chars() has pushed older data from DMA rx_buf upon suspend. The sequence in suspend routine needs proper locking to avoid this. Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com> Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com> Link: https://lore.kernel.org/r/20211025134229.8456-4-erwan.leray@foss.st.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-26serial: stm32: terminate / restart DMA transfer at suspend / resumeErwan Le Ray
DMA prevents the system to suspend when an UART RX wake-up source is using DMA. DMA can't suspend while DMA channels are still active. Terminate DMA transfer at suspend, and restart a new DMA transfer at resume. Create stm32_usart_start_rx_dma_cyclic function to factorize dma RX initialization. Move RX DMA code related to wakeup into stm32_usart_serial_en_wakeup() routine to ease further improvements on wakeup from low power modes. Don't enable/disable wakeup on uninitialized port. There may be data residue in the RX FIFO while suspending. Flush it at suspend time. Receiver timeout interrupt won't trigger later in low power mode, so call stm32_usart_receive_chars() in case there's data to handle. Signed-off-by: Valentin Caron <valentin.caron@foss.st.com> Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com> Link: https://lore.kernel.org/r/20211025134229.8456-3-erwan.leray@foss.st.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-26serial: stm32: rework RX dma initialization and releaseErwan Le Ray
The RX DMA channel is kept active forever (from the probe). That prevents going to low power mode when it is used. This change moves the DMA configuration and enabling procedures to startup routine to allow transition to low power mode. The DMA disabling procedure is implemented in stop_rx routine as this ops has to stop characters reception, and DMA transation in shutdown. Clean useless dma_async_tx_descriptor initialization to NULL value. Signed-off-by: Valentin Caron <valentin.caron@foss.st.com> Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com> Link: https://lore.kernel.org/r/20211025134229.8456-2-erwan.leray@foss.st.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-26serial: 8250_pci: Remove empty stub pci_quatech_exit()Andy Shevchenko
The ->exit() callback is checked for presence anyway, no need to have an empty stub. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20211026133452.61657-2-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-26serial: 8250_pci: Replace custom pci_match_id() implementationAndy Shevchenko
Replace pci_quatech_amcc() with generic pci_match_id(). Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20211026133452.61657-1-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-26serial: xilinx_uartps: Fix race condition causing stuck TXAnssi Hannula
xilinx_uartps .start_tx() clears TXEMPTY when enabling TXEMPTY to avoid any previous TXEVENT event asserting the UART interrupt. This clear operation is done immediately after filling the TX FIFO. However, if the bytes inserted by cdns_uart_handle_tx() are consumed by the UART before the TXEMPTY is cleared, the clear operation eats the new TXEMPTY event as well, causing cdns_uart_isr() to never receive the TXEMPTY event. If there are bytes still queued in circbuf, TX will get stuck as they will never get transferred to FIFO (unless new bytes are queued to circbuf in which case .start_tx() is called again). While the racy missed TXEMPTY occurs fairly often with short data sequences (e.g. write 1 byte), in those cases circbuf is usually empty so no action on TXEMPTY would have been needed anyway. On the other hand, longer data sequences make the race much more unlikely as UART takes longer to consume the TX FIFO. Therefore it is rare for this race to cause visible issues in general. Fix the race by clearing the TXEMPTY bit in ISR *before* filling the FIFO. The TXEMPTY bit in ISR will only get asserted at the exact moment the TX FIFO *becomes* empty, so clearing the bit before filling FIFO does not cause an extra immediate assertion even if the FIFO is initially empty. This is hard to reproduce directly on a normal system, but inserting e.g. udelay(200) after cdns_uart_handle_tx(port), setting 4000000 baud, and then running "dd if=/dev/zero bs=128 of=/dev/ttyPS0 count=50" reliably reproduces the issue on my ZynqMP test system unless this fix is applied. Fixes: 85baf542d54e ("tty: xuartps: support 64 byte FIFO size") Signed-off-by: Anssi Hannula <anssi.hannula@bitwise.fi> Link: https://lore.kernel.org/r/20211026102741.2910441-1-anssi.hannula@bitwise.fi Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-26serial: sunzilog: Mark sunzilog_putchar() __maybe_unusedGeert Uytterhoeven
If CONSOLE_POLL=n, CONFIG_SERIAL_SUNZILOG_CONSOLE=n, and CONFIG_SERIO=m: drivers/tty/serial/sunzilog.c:1128:13: error: ‘sunzilog_putchar’ defined but not used [-Werror=unused-function] 1128 | static void sunzilog_putchar(struct uart_port *port, int ch) | ^~~~~~~~~~~~~~~~ Fix this by marking sunzilog_putchar() __maybe_unused. Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Link: https://lore.kernel.org/r/20211026080426.2444756-1-geert@linux-m68k.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-26Revert "tty: hvc: pass DMA capable memory to put_chars()"Greg Kroah-Hartman
This reverts commit 0986d7bc5598f5df30e3db777d00e73890c97627. It still has some issues and needs to be dropped at this point in time. Link: https://lore.kernel.org/r/208f7a41-a9fa-630c-cb44-c37c503f3a72@kernel.org Reported-by: Jiri Slaby <jirislaby@kernel.org> Cc: Xianting Tian <xianting.tian@linux.alibaba.com> Cc: Shile Zhang <shile.zhang@linux.alibaba.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-26serial: 8250_pci: Replace dev_*() by pci_*() macrosAndy Shevchenko
PCI subsystem provides convenient shortcut macros for message printing. Use those macros instead of dev_*(). Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Jiri Slaby <jslaby@kernel.org> Link: https://lore.kernel.org/r/20211022135147.70965-3-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-26serial: 8250_pci: Get rid of redundant 'else' keywordAndy Shevchenko
The 'else' keyword is not needed when previous conditional branch returns to the upper layer. Get rid of redundant 'else' keyword in such cases. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Jiri Slaby <jslaby@kernel.org> Link: https://lore.kernel.org/r/20211022135147.70965-2-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-26serial: 8250_pci: Refactor the loop in pci_ite887x_init()Andy Shevchenko
The loop can be refactored by using ARRAY_SIZE() instead of NULL terminator. This reduces code base and makes it easier to read and understand. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Jiri Slaby <jslaby@kernel.org> Link: https://lore.kernel.org/r/20211022135147.70965-1-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-21tty: add rpmsg driverArnaud Pouliquen
This driver exposes a standard TTY interface on top of the rpmsg framework through a rpmsg service. This driver supports multi-instances, offering a /dev/ttyRPMSGx entry per rpmsg endpoint. Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com> Link: https://lore.kernel.org/r/20211015094701.5732-3-arnaud.pouliquen@foss.st.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-21serial: 8250_dw: drop bogus uartclk optimisationJohan Hovold
The driver was updating the port uartclk before setting the new rate in an attempt to avoid having the clock notifier redundantly update the divisors. The set_termios() callback is however called under the termios semaphore and tty-port mutex so the worker scheduled by the clock notifier will block in serial8250_update_uartclk() until the uartclk and divisors have been updated anyway. Drop the unnecessary swaps and incorrect comment and simply update the uartclk field if the clock-rate change was successful. Tested-by: Serge Semin <fancer.lancer@gmail.com> Reviewed-by: Serge Semin <fancer.lancer@gmail.com> Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Johan Hovold <johan@kernel.org> Link: https://lore.kernel.org/r/20211015111422.1027-4-johan@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-21serial: 8250: rename unlock labelsJohan Hovold
Rename a couple of oddly named labels that are used to unlock before returning after what they do (rather than after the context they are used in) to improve readability. Tested-by: Serge Semin <fancer.lancer@gmail.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Serge Semin <fancer.lancer@gmail.com> Signed-off-by: Johan Hovold <johan@kernel.org> Link: https://lore.kernel.org/r/20211015111422.1027-3-johan@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-21serial: 8250: fix racy uartclk updateJohan Hovold
Commit 868f3ee6e452 ("serial: 8250: Add 8250 port clock update method") added a hack to support SoCs where the UART reference clock can change behind the back of the driver but failed to add the proper locking. First, make sure to take a reference to the tty struct to avoid dereferencing a NULL pointer if the clock change races with a hangup. Second, the termios semaphore must be held during the update to prevent a racing termios change. Fixes: 868f3ee6e452 ("serial: 8250: Add 8250 port clock update method") Fixes: c8dff3aa8241 ("serial: 8250: Skip uninitialized TTY port baud rate update") Cc: stable@vger.kernel.org # 5.9 Cc: Serge Semin <Sergey.Semin@baikalelectronics.ru> Tested-by: Serge Semin <fancer.lancer@gmail.com> Reviewed-by: Serge Semin <fancer.lancer@gmail.com> Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Johan Hovold <johan@kernel.org> Link: https://lore.kernel.org/r/20211015111422.1027-2-johan@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-21serial: stm32: update throttle and unthrottle ops for dma modeErwan Le Ray
Disable DMA request line (if enabled) to switch in PIO mode in throttle ops, so the RX data gets queues into the FIFO. The hardware flow control is triggered when the RX FIFO is full. Switch back to DMA mode (re-enable DMA request line) in unthrottle ops. Hardware flow control is stopped when FIFO is not full anymore. Signed-off-by: Valentin Caron <valentin.caron@foss.st.com> Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com> Link: https://lore.kernel.org/r/20211020150332.10214-4-erwan.leray@foss.st.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-21serial: stm32: rework RX over DMAErwan Le Ray
This patch reworks RX support over DMA to improve reliability: - change dma buffer cyclic configuration by using 2 periods. DMA buffer data are handled by a flip-flop between the 2 periods in order to avoid risk of data loss/corruption - change the size of dma buffer to 4096 to limit overruns - add rx errors management (breaks, parity, framing and overrun). When an error occurs on the uart line, the dma request line is masked at HW level. The SW must 1st clear DMAR (dma request line enable), to handle the error, then re-enable DMAR to recover. So, any correct data is taken from the DMA buffer, before handling the error itself. Then errors are handled from RDR/ISR/FIFO (e.g. in PIO mode). Last, DMA reception is resumed. - add a condition on DMA request line in DMA RX routines in order to switch to PIO mode when no DMA request line is disabled, even if the DMA channel is still enabled. When the UART is wakeup source and is configured to use DMA for RX, any incoming data that wakes up the system isn't correctly received. At data reception, the irq_handler handles the WUF irq, and then the data reception over DMA. As the DMA transfer has been terminated at suspend, and will be restored by resume callback (which has no yet been called by system), the data can't be received. The wake-up data has to be handled in PIO mode while suspend callback has not been called. Signed-off-by: Valentin Caron <valentin.caron@foss.st.com> Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com> Link: https://lore.kernel.org/r/20211020150332.10214-3-erwan.leray@foss.st.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-21serial: stm32: re-introduce an irq flag condition in usart_receive_charsErwan Le Ray
Re-introduce an irq flag condition in usart_receive_chars. This condition has been deleted by commit 75f4e830fa9c ("serial: do not restore interrupt state in sysrq helper"). This code was present to handle threaded case, and has been removed because it is no more needed in this case. Nevertheless an irq safe lock is still needed in some cases, when DMA should be stopped to receive errors or breaks in PIO mode. This patch is a precursor to the complete rework or stm32 serial driver DMA implementation. Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com> Link: https://lore.kernel.org/r/20211020150332.10214-2-erwan.leray@foss.st.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-21tty: hvc: pass DMA capable memory to put_chars()Xianting Tian
As well known, hvc backend can register its opertions to hvc backend. the operations contain put_chars(), get_chars() and so on. Some hvc backend may do dma in its operations. eg, put_chars() of virtio-console. But in the code of hvc framework, it may pass DMA incapable memory to put_chars() under a specific configuration, which is explained in commit c4baad5029(virtio-console: avoid DMA from stack): 1, c[] is on stack, hvc_console_print(): char c[N_OUTBUF] __ALIGNED__; cons_ops[index]->put_chars(vtermnos[index], c, i); 2, ch is on stack, static void hvc_poll_put_char(,,char ch) { struct tty_struct *tty = driver->ttys[0]; struct hvc_struct *hp = tty->driver_data; int n; do { n = hp->ops->put_chars(hp->vtermno, &ch, 1); } while (n <= 0); } Commit c4baad5029 is just the fix to avoid DMA from stack memory, which is passed to virtio-console by hvc framework in above code. But I think the fix is aggressive, it directly uses kmemdup() to alloc new buffer from kmalloc area and do memcpy no matter the memory is in kmalloc area or not. But most importantly, it should better be fixed in the hvc framework, by changing it to never pass stack memory to the put_chars() function in the first place. Otherwise, we still face the same issue if a new hvc backend using dma added in the furture. In this patch, add 'char cons_outbuf[]' as part of 'struct hvc_struct', so hp->cons_outbuf is no longer the stack memory, we can use it in above cases safely. We also add lock to protect cons_outbuf instead of using the global lock of hvc. Introduce another array(cons_hvcs[]) for hvc pointers next to the cons_ops[] and vtermnos[] arrays. With the array, we can easily find hvc's cons_outbuf and its lock. With the patch, we can revert the fix c4baad5029. Signed-off-by: Xianting Tian <xianting.tian@linux.alibaba.com> Signed-off-by: Shile Zhang <shile.zhang@linux.alibaba.com> Link: https://lore.kernel.org/r/20211015024658.1353987-3-xianting.tian@linux.alibaba.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-21tty: hvc: use correct dma alignment sizeXianting Tian
Use L1_CACHE_BYTES as the dma alignment size, use 'sizeof(long)' as dma alignment is wrong. Signed-off-by: Xianting Tian <xianting.tian@linux.alibaba.com> Signed-off-by: Shile Zhang <shile.zhang@linux.alibaba.com> Link: https://lore.kernel.org/r/20211015024658.1353987-2-xianting.tian@linux.alibaba.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-21serial: imx: disable console clocks on unregisterFrancesco Dolcini
During console setup imx_uart_console_setup() enables clocks, but they are never disabled when the console is unregistered, this leads to clk_prepare_enable() being called multiple times without a matching clk_disable_unprepare() in case of console unregister. Ensure that clock enable/disable are balanced adding clk_disable_unprepare() in the console exit callback. Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com> Link: https://lore.kernel.org/r/20211020192643.476895-3-francesco.dolcini@toradex.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-21serial: imx: fix detach/attach of serial consoleStefan Agner
If the device used as a serial console gets detached/attached at runtime, register_console() will try to call imx_uart_setup_console(), but this is not possible since it is marked as __init. For instance # cat /sys/devices/virtual/tty/console/active tty1 ttymxc0 # echo -n N > /sys/devices/virtual/tty/console/subsystem/ttymxc0/console # echo -n Y > /sys/devices/virtual/tty/console/subsystem/ttymxc0/console [ 73.166649] 8<--- cut here --- [ 73.167005] Unable to handle kernel paging request at virtual address c154d928 [ 73.167601] pgd = 55433e84 [ 73.167875] [c154d928] *pgd=8141941e(bad) [ 73.168304] Internal error: Oops: 8000000d [#1] SMP ARM [ 73.168429] Modules linked in: [ 73.168522] CPU: 0 PID: 536 Comm: sh Not tainted 5.15.0-rc6-00056-g3968ddcf05fb #3 [ 73.168675] Hardware name: Freescale i.MX6 Ultralite (Device Tree) [ 73.168791] PC is at imx_uart_console_setup+0x0/0x238 [ 73.168927] LR is at try_enable_new_console+0x98/0x124 [ 73.169056] pc : [<c154d928>] lr : [<c0196f44>] psr: a0000013 [ 73.169178] sp : c2ef5e70 ip : 00000000 fp : 00000000 [ 73.169281] r10: 00000000 r9 : c02cf970 r8 : 00000000 [ 73.169389] r7 : 00000001 r6 : 00000001 r5 : c1760164 r4 : c1e0fb08 [ 73.169512] r3 : c154d928 r2 : 00000000 r1 : efffcbd1 r0 : c1760164 [ 73.169641] Flags: NzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none [ 73.169782] Control: 10c5387d Table: 8345406a DAC: 00000051 [ 73.169895] Register r0 information: non-slab/vmalloc memory [ 73.170032] Register r1 information: non-slab/vmalloc memory [ 73.170158] Register r2 information: NULL pointer [ 73.170273] Register r3 information: non-slab/vmalloc memory [ 73.170397] Register r4 information: non-slab/vmalloc memory [ 73.170521] Register r5 information: non-slab/vmalloc memory [ 73.170647] Register r6 information: non-paged memory [ 73.170771] Register r7 information: non-paged memory [ 73.170892] Register r8 information: NULL pointer [ 73.171009] Register r9 information: non-slab/vmalloc memory [ 73.171142] Register r10 information: NULL pointer [ 73.171259] Register r11 information: NULL pointer [ 73.171375] Register r12 information: NULL pointer [ 73.171494] Process sh (pid: 536, stack limit = 0xcd1ba82f) [ 73.171621] Stack: (0xc2ef5e70 to 0xc2ef6000) [ 73.171731] 5e60: ???????? ???????? ???????? ???????? [ 73.171899] 5e80: ???????? ???????? ???????? ???????? ???????? ???????? ???????? ???????? [ 73.172059] 5ea0: ???????? ???????? ???????? ???????? ???????? ???????? ???????? ???????? [ 73.172217] 5ec0: ???????? ???????? ???????? ???????? ???????? ???????? ???????? ???????? [ 73.172377] 5ee0: ???????? ???????? ???????? ???????? ???????? ???????? ???????? ???????? [ 73.172537] 5f00: ???????? ???????? ???????? ???????? ???????? ???????? ???????? ???????? [ 73.172698] 5f20: ???????? ???????? ???????? ???????? ???????? ???????? ???????? ???????? [ 73.172856] 5f40: ???????? ???????? ???????? ???????? ???????? ???????? ???????? ???????? [ 73.173016] 5f60: ???????? ???????? ???????? ???????? ???????? ???????? ???????? ???????? [ 73.173177] 5f80: ???????? ???????? ???????? ???????? ???????? ???????? ???????? ???????? [ 73.173336] 5fa0: ???????? ???????? ???????? ???????? ???????? ???????? ???????? ???????? [ 73.173496] 5fc0: ???????? ???????? ???????? ???????? ???????? ???????? ???????? ???????? [ 73.173654] 5fe0: ???????? ???????? ???????? ???????? ???????? ???????? ???????? ???????? [ 73.173826] [<c0196f44>] (try_enable_new_console) from [<c01984a8>] (register_console+0x10c/0x2ec) [ 73.174053] [<c01984a8>] (register_console) from [<c06e2c90>] (console_store+0x14c/0x168) [ 73.174262] [<c06e2c90>] (console_store) from [<c0383718>] (kernfs_fop_write_iter+0x110/0x1cc) [ 73.174470] [<c0383718>] (kernfs_fop_write_iter) from [<c02cf5f4>] (vfs_write+0x31c/0x548) [ 73.174679] [<c02cf5f4>] (vfs_write) from [<c02cf970>] (ksys_write+0x60/0xec) [ 73.174863] [<c02cf970>] (ksys_write) from [<c0100080>] (ret_fast_syscall+0x0/0x1c) [ 73.175052] Exception stack(0xc2ef5fa8 to 0xc2ef5ff0) [ 73.175167] 5fa0: ???????? ???????? ???????? ???????? ???????? ???????? [ 73.175327] 5fc0: ???????? ???????? ???????? ???????? ???????? ???????? ???????? ???????? [ 73.175486] 5fe0: ???????? ???????? ???????? ???????? [ 73.175608] Code: 00000000 00000000 00000000 00000000 (00000000) [ 73.175744] ---[ end trace 9b75121265109bf1 ]--- A similar issue could be triggered by unbinding/binding the serial console device [*]. Drop __init so that imx_uart_setup_console() can be safely called at runtime. [*] https://lore.kernel.org/all/20181114174940.7865-3-stefan@agner.ch/ Fixes: a3cb39d258ef ("serial: core: Allow detach and attach serial device for console") Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Stefan Agner <stefan@agner.ch> Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com> Link: https://lore.kernel.org/r/20211020192643.476895-2-francesco.dolcini@toradex.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-10-20workqueue: Introduce show_one_worker_pool and show_one_workqueue.Imran Khan
Currently show_workqueue_state shows the state of all workqueues and of all worker pools. In certain cases we may need to dump state of only a specific workqueue or worker pool. For example in destroy_workqueue we only need to show state of the workqueue which is getting destroyed. So rename show_workqueue_state to show_all_workqueues(to signify it dumps state of all busy workqueues) and divide it into more granular functions (show_one_workqueue and show_one_worker_pool), that would show states of individual workqueues and worker pools and can be used in cases such as the one mentioned above. Also, as mentioned earlier, make destroy_workqueue dump data pertaining to only the workqueue that is being destroyed and make user(s) of earlier interface(show_workqueue_state), use new interface (show_all_workqueues). Signed-off-by: Imran Khan <imran.f.khan@oracle.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2021-10-18tty: tty_buffer: Fix the softlockup issue in flush_to_ldiscGuanghui Feng
When running ltp testcase(ltp/testcases/kernel/pty/pty04.c) with arm64, there is a soft lockup, which look like this one: Workqueue: events_unbound flush_to_ldisc Call trace: dump_backtrace+0x0/0x1ec show_stack+0x24/0x30 dump_stack+0xd0/0x128 panic+0x15c/0x374 watchdog_timer_fn+0x2b8/0x304 __run_hrtimer+0x88/0x2c0 __hrtimer_run_queues+0xa4/0x120 hrtimer_interrupt+0xfc/0x270 arch_timer_handler_phys+0x40/0x50 handle_percpu_devid_irq+0x94/0x220 __handle_domain_irq+0x88/0xf0 gic_handle_irq+0x84/0xfc el1_irq+0xc8/0x180 slip_unesc+0x80/0x214 [slip] tty_ldisc_receive_buf+0x64/0x80 tty_port_default_receive_buf+0x50/0x90 flush_to_ldisc+0xbc/0x110 process_one_work+0x1d4/0x4b0 worker_thread+0x180/0x430 kthread+0x11c/0x120 In the testcase pty04, The first process call the write syscall to send data to the pty master. At the same time, the workqueue will do the flush_to_ldisc to pop data in a loop until there is no more data left. When the sender and workqueue running in different core, the sender sends data fastly in full time which will result in workqueue doing work in loop for a long time and occuring softlockup in flush_to_ldisc with kernel configured without preempt. So I add need_resched check and cond_resched in the flush_to_ldisc loop to avoid it. Signed-off-by: Guanghui Feng <guanghuifeng@linux.alibaba.com> Link: https://lore.kernel.org/r/1633961304-24759-1-git-send-email-guanghuifeng@linux.alibaba.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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