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2020-03-07sysctl/sysrq: Remove __sysrq_enabled copyDmitry Safonov1-0/+12
Many embedded boards have a disconnected TTL level serial which can generate some garbage that can lead to spurious false sysrq detects. Currently, sysrq can be either completely disabled for serial console or always disabled (with CONFIG_MAGIC_SYSRQ_SERIAL), since commit 732dbf3a6104 ("serial: do not accept sysrq characters via serial port") At Arista, we have such boards that can generate BREAK and random garbage. While disabling sysrq for serial console would solve the problem with spurious false sysrq triggers, it's also desirable to have a way to enable sysrq back. Having the way to enable sysrq was beneficial to debug lockups with a manual investigation in field and on the other side preventing false sysrq detections. As a preparation to add sysrq_toggle_support() call into uart, remove a private copy of sysrq_enabled from sysctl - it should reflect the actual status of sysrq. Furthermore, the private copy isn't correct already in case sysrq_always_enabled is true. So, remove __sysrq_enabled and use a getter-helper sysrq_mask() to check sysrq_key_op enabled status. Cc: Iurii Zaikin <[email protected]> Cc: Jiri Slaby <[email protected]> Cc: Luis Chamberlain <[email protected]> Cc: Kees Cook <[email protected]> Cc: [email protected] Signed-off-by: Dmitry Safonov <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-03-07serial: 8250: Support console on software emulated rs485 portsLukas Wunner1-0/+13
Commit e490c9144cfa ("tty: Add software emulated RS485 support for 8250") introduced support to use RTS as an rs485 Transmit Enable signal if data is transmitted through the tty layer. Console messages bypass the tty layer and instead are emitted via serial8250_console_write(). Amend that function to drive RTS as well, allowing for a console on rs485 ports. Note that serial8250_console_write() may be called concurrently to the tty layer accessing the port. The two protect their accesses with the port lock, but serial8250_console_write() may find RTS still being asserted by the tty layer, in which case it shouldn't be deasserted after the console message has been printed. Recognize such situations by checking the em485->tx_stopped flag. If a delay_rts_before_send or delay_rts_after_send has been specified, serial8250_console_write() busy-waits for its duration. Optimizations for those wait times are conceivable: E.g. if RTS is already asserted, we could check whether em485->start_tx_timer is active and wait only for the remaining expire time. But this would require calling into the hrtimer infrastructure, which involves acquiring locks and potentially reprogramming timer hardware. Such operations seem too risky in the context of console printout, which needs to work even when the kernel has crashed and emits a BUG splat. So I've gone with a simplistic solution which just always waits for the full delay. Signed-off-by: Lukas Wunner <[email protected]> Cc: Matwey V. Kornilov <[email protected]> Link: https://lore.kernel.org/r/65edffce4670a19e598015c03cbe46f1ffd93e43.1582895077.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-03-07serial: 8250_bcm2835aux: Support rs485 software emulationLukas Wunner1-2/+60
Amend 8250_bcm2835aux.c to support rs485 as introduced for 8250_omap.c by commit e490c9144cfa ("tty: Add software emulated RS485 support for 8250"). The bcm2835aux differs from omap chips by inverting the meaning of RTS in the MCR register: If the bit is clear, RTS is high. With omap, it's apparently the other way round. Moreover, omap achieves half-duplex mode by disabling the UART_IER_RDI interrupt and clearing the RX FIFO when TX stops. This approach doesn't work on bcm2835aux because the UART_LSR_DR bit is set even when UART_IER_RDI is disabled. Consequently, serial8250_handle_irq() invokes serial8250_rx_chars() to empty the FIFO and characters are received even though the user requested half-duplex. Solve by disabling the receiver using the non-standard CNTL register. Cache that register in the driver's private data for performance. Set the private data pointer before calling serial8250_register_8250_port() to prevent a null pointer deref in case one of the rs485 callbacks is invoked immediately after port registration. Signed-off-by: Lukas Wunner <[email protected]> Cc: Matwey V. Kornilov <[email protected]> Link: https://lore.kernel.org/r/dd86460e20a8f979b7272a0bde73640312b902b1.1582895077.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-03-07serial: 8250: Generalize rs485 software emulationLukas Wunner5-31/+64
Commit e490c9144cfa ("tty: Add software emulated RS485 support for 8250") introduced support to use RTS as an rs485 Transmit Enable signal. So far the only drivers taking advantage of it are 8250_omap.c and 8250_of.c. We're about to make use of the feature in 8250_bcm2835aux.c as well. The bcm2835aux differs from omap chips by inverting the meaning of RTS in the MCR register. Moreover, omap achieves half-duplex mode by disabling the RX interrupt and clearing the RX FIFO when TX stops. The bcm2835aux requires disabling the receiver instead. Support these behavioral differences by generalizing the rs485 emulation: Introduce ->rs485_start_tx() and ->rs485_stop_tx() callbacks in struct uart_8250_port, provide generic implementations containing the existing code and use them as callbacks in 8250_omap.c and 8250_of.c. start_tx_rs485() is idempotent in that it recognizes whether RTS is already asserted. Achieve the same by introducing a tx_stopped flag in struct uart_8250_em485. This may even perform a little better on arches where memory access is faster than mmio access. Signed-off-by: Lukas Wunner <[email protected]> Cc: Matwey V. Kornilov <[email protected]> Link: https://lore.kernel.org/r/5ac0464ae4414708e723a1e0d52b0c1b2bd41b9b.1582895077.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-03-07serial: 8250: Deduplicate rs485 active_timer assignmentLukas Wunner1-2/+1
When rs485 transmission over an 8250 port stops, __stop_tx() assigns active_timer = NULL before calling __stop_tx_rs485(). That function in turn either assigns active_timer = stop_tx_timer and rearms the timer (in case a delay_rts_after_send needs to be observed) or directly calls __do_stop_tx_rs485(). Move the assignment active_timer = NULL to __stop_tx_rs485() into the branch which directly calls __do_stop_tx_rs485(), thereby avoiding a duplicate assignment and simplifying the code. Signed-off-by: Lukas Wunner <[email protected]> Cc: Matwey V. Kornilov <[email protected]> Link: https://lore.kernel.org/r/bca638405550eaf92f0c6060b553b687f35885e0.1582895077.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-03-07serial: 8250: Sanitize rs485 config harderLukas Wunner1-0/+8
Amend the generic ->rs485_config() callback to sanitize RTS polarity and zero-fill the padding (in addition to the existing sanitization of the RTS delays). Signed-off-by: Lukas Wunner <[email protected]> Cc: Matwey V. Kornilov <[email protected]> Link: https://lore.kernel.org/r/ff833721bc372d38678f289eb2a44dbf016d5203.1582895077.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-03-07serial: 8250: Deduplicate ->rs485_config() callbackLukas Wunner4-65/+42
Commit e490c9144cfa ("tty: Add software emulated RS485 support for 8250") introduced support to use RTS as an rs485 Transmit Enable signal. Drivers opt in to the feature by calling serial8250_em485_init() from their ->rs485_config() callback. So far there are two drivers doing that, 8250_omap.c and 8250_of.c. Both use an identical callback. We're about to add a third user of that callback, therefore deduplicate it and move it to 8250_port.c. Drivers now opt in to rs485 software emulation by assigning the generic serial8250_rs485_config() callback introduced herein to their .rs485_config struct member. This change allows unexporting serial8250_em485_init() and declaring it static. Signed-off-by: Lukas Wunner <[email protected]> Cc: Matwey V. Kornilov <[email protected]> Cc: Heiko Schocher <[email protected]> Link: https://lore.kernel.org/r/fcef63642dc4eae41ae7842d23747b2bf5d40285.1582895077.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-03-07serial: 8250: Support rs485 devicetree propertiesLukas Wunner2-1/+6
Retrieve rs485 devicetree properties on registration of 8250 ports in case they are attached to an rs485 transceiver. If the property "linux,rs485-enabled-at-boot-time" is present, invoke the ->rs485_config() callback to immediately deassert RTS, thereby ceasing control of the bus. Signed-off-by: Lukas Wunner <[email protected]> Cc: Giulio Benetti <[email protected]> Cc: Uwe Kleine-König <[email protected]> Link: https://lore.kernel.org/r/5908ea89b7f9da54872d6634b606d83db032297a.1582895077.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-03-07serial: 8250: Don't touch RTS modem control while in rs485 modeLukas Wunner1-0/+7
serial8250_do_set_mctrl() currently allows modifying the RTS modem control line even when RTS is used as an rs485 Transmit Enable signal. It is thus possible for user space to interfere with rs485 communication by invoking a TIOCMSET ioctl(). Ignore such change requests and retain the current RTS polarity when in rs485 mode. Note that serial8250_set_mctrl() is always called with port->lock held, so there's no risk that RTS is changed concurrently. Signed-off-by: Lukas Wunner <[email protected]> Cc: Matwey V. Kornilov <[email protected]> Link: https://lore.kernel.org/r/b1ce34ca9bc4d7bdc6e9852fcf30b1f4e37c8a80.1582895077.git.lukas@wunner.de Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-03-07serial: earlycon: prefer EARLYCON_DECLARE() variantMichael Walle1-0/+11
If a driver exposes early consoles with EARLYCON_DECLARE() and OF_EARLYCON_DECLARE(), pefer the non-OF variant if the user specifies it by earlycon=<driver>,<options> The rationale behind this is that some drivers register multiple setup functions under the same driver name. Eg. OF_EARLYCON_DECLARE(lpuart, "fsl,vf610-lpuart", lpuart_early_console_setup); OF_EARLYCON_DECLARE(lpuart32, "fsl,ls1021a-lpuart", lpuart32_early_console_setup); OF_EARLYCON_DECLARE(lpuart32, "fsl,imx7ulp-lpuart", lpuart32_imx_early_console_setup); EARLYCON_DECLARE(lpuart, lpuart_early_console_setup); EARLYCON_DECLARE(lpuart32, lpuart32_early_console_setup); It depends on the order of the entries which console_setup() actually gets called. To make things worse, I guess it also depends on the compiler how these are ordered. Thus always prefer the EARLYCON_DECLARE() ones. Signed-off-by: Michael Walle <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-03-07tty: serial: Use the correct style for SPDX License IdentifierNishad Kamdar12-12/+12
This patch corrects the SPDX License Identifier style in header files related to tty serial drivers. For C header files Documentation/process/license-rules.rst mandates C-like comments (opposed to C source files where C++ style should be used). Changes made by using a script provided by Joe Perches here: https://lkml.org/lkml/2019/2/7/46. Suggested-by: Joe Perches <[email protected]> Signed-off-by: Nishad Kamdar <[email protected]> Link: https://lore.kernel.org/r/20200301204517.GA10368@nishad Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-03-06tty: serial: fsl_lpuart: free IDs allocated by IDAMichael Walle1-15/+24
Since commit 3bc3206e1c0f ("serial: fsl_lpuart: Remove the alias node dependence") the port line number can also be allocated by IDA, but in case of an error the ID will no be removed again. More importantly, any ID will be freed in remove(), even if it wasn't allocated but instead fetched by of_alias_get_id(). If it was not allocated by IDA there will be a warning: WARN(1, "ida_free called for id=%d which is not allocated.\n", id); Move the ID allocation more to the end of the probe() so that we still can use plain return in the first error cases. Fixes: 3bc3206e1c0f ("serial: fsl_lpuart: Remove the alias node dependence") Signed-off-by: Michael Walle <[email protected]> Cc: stable <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-03-06Revert "tty: serial: fsl_lpuart: drop EARLYCON_DECLARE"Michael Walle1-0/+2
This reverts commit a659652f6169240a5818cb244b280c5a362ef5a4. This broke the earlycon on LS1021A processors because the order of the earlycon_setup() functions were changed. Before the commit the normal lpuart32_early_console_setup() was called. After the commit the lpuart32_imx_early_console_setup() is called instead. Fixes: a659652f6169 ("tty: serial: fsl_lpuart: drop EARLYCON_DECLARE") Signed-off-by: Michael Walle <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-03-06serdev: Fix detection of UART devices on Apple machines.Ronald Tschalär1-0/+10
On Apple devices the _CRS method returns an empty resource template, and the resource settings are instead provided by the _DSM method. But commit 33364d63c75d6182fa369cea80315cf1bb0ee38e (serdev: Add ACPI devices by ResourceSource field) changed the search for serdev devices to require valid, non-empty resource template, thereby breaking Apple devices and causing bluetooth devices to not be found. This expands the check so that if we don't find a valid template, and we're on an Apple machine, then just check for the device being an immediate child of the controller and having a "baud" property. Cc: <[email protected]> # 5.5 Fixes: 33364d63c75d ("serdev: Add ACPI devices by ResourceSource field") Signed-off-by: Ronald Tschalär <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-03-06tty: serial: make SERIAL_SPRD not depend on ARCH_SPRDChunyan Zhang1-1/+0
Remove the dependency with ARCH_SPRD from sprd serial/console Kconfig-s, since we want them can be built-in when ARCH_SPRD is set as 'm'. Signed-off-by: Chunyan Zhang <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-03-06serial: 8250_lpss: Add ->setup() for Elkhart Lake portsAndy Shevchenko1-0/+6
The ->setup() callback is mandatory for the devices. Provide it for Elkhart Lake UART ports. Note, for time being it's empty, but in the future it might require an additional configuration such as DMA. Reported-by: Raymond Tan <[email protected]> Signed-off-by: Andy Shevchenko <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-03-06serial: 8250-mtk: modify mtk uart power and clock managementChangqi Hu1-18/+32
MTK uart design no need to control uart clock, so we just control bus clock in runtime function. Add uart clock used count to avoid repeatedly switching the clock. Signed-off-by: Changqi Hu <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-03-06tty: imx serial: Implement support for reversing TX and RX polarityGeorge Hilliard1-16/+28
The peripheral has support for inverting its input and/or output signals. This is useful if the hardware flips polarity of the peripheral's signal, such as swapped +/- pins on an RS-422 transceiver, or an inverting level shifter. Add support for these control registers via the device tree binding. As part of this change, make the writes of the various registers more uniform by moving the UCR3 block up near the other registers' blocks, since the INVT bit must be set before enabling the peripheral. Signed-off-by: George Hilliard <[email protected]> Acked-by: Uwe Kleine-König <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-03-06serial: ar933x_uart: add RS485 supportDaniel Golle2-6/+108
Emulate half-duplex operation and use mctrl_gpio to add support for RS485 tranceiver with transmit/receive switch hooked to RTS GPIO line. This is needed to make use of the RS485 port found on Teltonika RUT955. Signed-off-by: Daniel Golle <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-03-06tty: serial: qcom_geni_serial: Fix GPIO swapping with workaroundRoja Rani Yarubandi1-0/+30
Add capability to support RX-TX, CTS-RTS pins swap in HW. Configure UART_IO_MACRO_CTRL register accordingly if RX-TX pair or CTS-RTS pair or both pairs swapped. Signed-off-by: Roja Rani Yarubandi <[email protected]> Reviewed-by: Stephen Boyd <[email protected]> Tested-by: Matthias Kaehlcke <[email protected]> Reviewed-by: Matthias Kaehlcke <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-03-06tty: serial: cpm_uart: Convert to use GPIO descriptorsLinus Walleij2-28/+24
The CPM UART (PowerPC) has an open coded GPIO modem control handling. Since I can't test this I can't just migrate it to the serial mctrl GPIO helper library though I wish I could. I do second best and convert it to GPIO descriptors at least. Cc: Rasmus Villemoes <[email protected]> Cc: Christophe Leroy <[email protected]> Signed-off-by: Linus Walleij <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-03-06tty: serial: lantiq: Drop GPIO includeLinus Walleij1-1/+0
Nothing in this driver uses the symbols from <linux/gpio.h> so drop this include. Cc: Rahul Tanwar <[email protected]> Cc: Songjun Wu <[email protected]> Cc: Martin Blumenstingl <[email protected]> Cc: John Crispin <[email protected]> Signed-off-by: Linus Walleij <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-03-06tty: serial: atmel_serial: Drop GPIO includesLinus Walleij1-3/+0
Nothing in this driver uses the symbols from these GPIO includes so drop them. These are probably just historical artifacts from befor mctrl_gpio was used. Cc: Ludovic Desroches <[email protected]> Cc: Razvan Stefanescu <[email protected]> Signed-off-by: Linus Walleij <[email protected]> Reviewed-by: Ludovic Desroches <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-03-06vt: selection, indent switch-case properlyJiri Slaby1-37/+35
Shift the cases one level left as this is how we are supposed to write the switch-case code according to the CodingStyle. Signed-off-by: Jiri Slaby <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-03-06vt: selection, remove redeclaration of poke_blanked_consoleJiri Slaby1-2/+0
It is declared in vt_kern.h, so no need to declare it in selection.c which includes the header. Signed-off-by: Jiri Slaby <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-03-06vt: switch vt_dont_switch to boolJiri Slaby1-3/+3
vt_dont_switch is pure boolean, no need for whole char. Signed-off-by: Jiri Slaby <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-03-06vt: selection, create struct from console selection globalsJiri Slaby1-46/+48
Move all the selection global variables to a structure vc_selection, instantiated as vc_sel. This helps to group all the variables together and see what should be protected by the embedded lock too. It might be used later also for per-console selection support. Signed-off-by: Jiri Slaby <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-03-06vt: selection, localize use_unicodeJiri Slaby1-16/+16
use_unicode needs not be global. It is used only in set_selection_kernel and sel_pos (a callee). It is also always set there prior calling sel_pos. So make use_unicode local and rename it to plain shorter "unicode". Finally, propagate it to sel_pos via parameter. Signed-off-by: Jiri Slaby <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-03-06vt: selection, remove 2 local variables from set_selection_kernelJiri Slaby1-9/+5
multiplier and mode are not actually needed: * multiplier is used only in kmalloc_array, so use "use_unicode ? 4 : 1" directly * mode is used only to assign a bool in this manner: if (cond) x = true; else x = false; So do "x = cond" directly. Signed-off-by: Jiri Slaby <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-03-05serial: 8250_exar: add support for ACCES cardsJay Dolan1-0/+33
Add ACCES VIDs and PIDs that use the Exar chips Signed-off-by: Jay Dolan <[email protected]> Cc: stable <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-03-05tty:serial:mvebu-uart:fix a wrong returntangbin1-1/+1
in this place, the function should return a negative value and the PTR_ERR already returns a negative,so return -PTR_ERR() is wrong. Signed-off-by: tangbin <[email protected]> Cc: stable <[email protected]> Acked-by: Jiri Slaby <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-02-28vt: selection, push sel_lock upJiri Slaby1-9/+7
sel_lock cannot nest in the console lock. Thanks to syzkaller, the kernel states firmly: > WARNING: possible circular locking dependency detected > 5.6.0-rc3-syzkaller #0 Not tainted > ------------------------------------------------------ > syz-executor.4/20336 is trying to acquire lock: > ffff8880a2e952a0 (&tty->termios_rwsem){++++}, at: tty_unthrottle+0x22/0x100 drivers/tty/tty_ioctl.c:136 > > but task is already holding lock: > ffffffff89462e70 (sel_lock){+.+.}, at: paste_selection+0x118/0x470 drivers/tty/vt/selection.c:374 > > which lock already depends on the new lock. > > the existing dependency chain (in reverse order) is: > > -> #2 (sel_lock){+.+.}: > mutex_lock_nested+0x1b/0x30 kernel/locking/mutex.c:1118 > set_selection_kernel+0x3b8/0x18a0 drivers/tty/vt/selection.c:217 > set_selection_user+0x63/0x80 drivers/tty/vt/selection.c:181 > tioclinux+0x103/0x530 drivers/tty/vt/vt.c:3050 > vt_ioctl+0x3f1/0x3a30 drivers/tty/vt/vt_ioctl.c:364 This is ioctl(TIOCL_SETSEL). Locks held on the path: console_lock -> sel_lock > -> #1 (console_lock){+.+.}: > console_lock+0x46/0x70 kernel/printk/printk.c:2289 > con_flush_chars+0x50/0x650 drivers/tty/vt/vt.c:3223 > n_tty_write+0xeae/0x1200 drivers/tty/n_tty.c:2350 > do_tty_write drivers/tty/tty_io.c:962 [inline] > tty_write+0x5a1/0x950 drivers/tty/tty_io.c:1046 This is write(). Locks held on the path: termios_rwsem -> console_lock > -> #0 (&tty->termios_rwsem){++++}: > down_write+0x57/0x140 kernel/locking/rwsem.c:1534 > tty_unthrottle+0x22/0x100 drivers/tty/tty_ioctl.c:136 > mkiss_receive_buf+0x12aa/0x1340 drivers/net/hamradio/mkiss.c:902 > tty_ldisc_receive_buf+0x12f/0x170 drivers/tty/tty_buffer.c:465 > paste_selection+0x346/0x470 drivers/tty/vt/selection.c:389 > tioclinux+0x121/0x530 drivers/tty/vt/vt.c:3055 > vt_ioctl+0x3f1/0x3a30 drivers/tty/vt/vt_ioctl.c:364 This is ioctl(TIOCL_PASTESEL). Locks held on the path: sel_lock -> termios_rwsem > other info that might help us debug this: > > Chain exists of: > &tty->termios_rwsem --> console_lock --> sel_lock Clearly. From the above, we have: console_lock -> sel_lock sel_lock -> termios_rwsem termios_rwsem -> console_lock Fix this by reversing the console_lock -> sel_lock dependency in ioctl(TIOCL_SETSEL). First, lock sel_lock, then console_lock. Signed-off-by: Jiri Slaby <[email protected]> Reported-by: [email protected] Fixes: 07e6124a1a46 ("vt: selection, close sel_buffer race") Cc: stable <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-02-28vt: selection, push console lock downJiri Slaby2-3/+12
We need to nest the console lock in sel_lock, so we have to push it down a bit. Fortunately, the callers of set_selection_* just lock the console lock around the function call. So moving it down is easy. In the next patch, we switch the order. Signed-off-by: Jiri Slaby <[email protected]> Fixes: 07e6124a1a46 ("vt: selection, close sel_buffer race") Cc: stable <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-02-24Merge 5.6-rc3 into tty-nextGreg Kroah-Hartman15-51/+102
We want the tty fixes in here as well. Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-02-23n_tty: Distribute switch variables for initializationKees Cook1-2/+2
Variables declared in a switch statement before any case statements cannot be automatically initialized with compiler instrumentation (as they are not part of any execution flow). With GCC's proposed automatic stack variable initialization feature, this triggers a warning (and they don't get initialized). Clang's automatic stack variable initialization (via CONFIG_INIT_STACK_ALL=y) doesn't throw a warning, but it also doesn't initialize such variables[1]. Note that these warnings (or silent skipping) happen before the dead-store elimination optimization phase, so even when the automatic initializations are later elided in favor of direct initializations, the warnings remain. To avoid these problems, move such variables into the "case" where they're used or lift them up into the main function body. drivers/tty/n_tty.c: In function ‘__process_echoes’: drivers/tty/n_tty.c:657:18: warning: statement will never be executed [-Wswitch-unreachable] 657 | unsigned int num_chars, num_bs; | ^~~~~~~~~ [1] https://bugs.llvm.org/show_bug.cgi?id=44916 Reviewed-by: Jiri Slaby <[email protected]> Signed-off-by: Kees Cook <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-02-21vt: ioctl, switch VT_IS_IN_USE and VT_BUSY to inlinesJiri Slaby1-7/+22
These two were macros. Switch them to static inlines, so that it's more understandable what they are doing. Signed-off-by: Jiri Slaby <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-02-21vt: selection, introduce vc_is_selJiri Slaby3-4/+10
Avoid global variables (namely sel_cons) by introducing vc_is_sel. It checks whether the parameter is the current selection console. This will help putting sel_cons to a struct later. Signed-off-by: Jiri Slaby <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-02-21n_hdlc: wrap a comment properlyJiri Slaby1-2/+4
Signed-off-by: Jiri Slaby <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-02-21n_hdlc: fix whitespace around binary operatorsJiri Slaby1-3/+3
Signed-off-by: Jiri Slaby <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-02-21n_hdlc: add missing spaces after commasJiri Slaby1-9/+9
Signed-off-by: Jiri Slaby <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-02-21n_hdlc: remove spaces between function name and (Jiri Slaby1-4/+4
Signed-off-by: Jiri Slaby <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-02-21n_hdlc: remove useless whitespace at line wrapsJiri Slaby1-37/+37
Do s@[ \t]\+$@@ s@ \+\t@\t@ on the file as there are many spaces at the begininning of lines and many spaces/tabs at EOLs. And vim screamed. git show -w is supposed to show no difference here. Signed-off-by: Jiri Slaby <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-02-21n_hdlc: use __func__ and pr_ print helpersJiri Slaby1-7/+7
* we mark the message in n_hdlc_tty_receive as error * we use __func__ instead of explicit function name * we switch the remaining prints to pr_* helpers Signed-off-by: Jiri Slaby <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-02-21n_hdlc: remove unneeded ifdefJiri Slaby1-2/+0
TTY_NO_WRITE_SPLIT is (always) defined in linux/tty.h, so no need to check for it. Signed-off-by: Jiri Slaby <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-02-21n_hdlc: switch tbusy and woke_up to boolsJiri Slaby1-8/+8
They are in fact bools, so save some bytes (8B on x86_64). Also describe @woke_up as we know what it is. Signed-off-by: Jiri Slaby <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-02-21n_hdlc: move tty_ldisc_ops to the bottomJiri Slaby1-31/+15
This makes forward declarations unnecessary. So drop them. Signed-off-by: Jiri Slaby <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-02-21n_hdlc: add helper for buffers allocationJiri Slaby1-22/+20
Given both rx and tx allocations do the same, add a new helper (n_hdlc_alloc_buf) and use it for both of them. This cleans up n_hdlc_alloc slightly. Signed-off-by: Jiri Slaby <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-02-21n_hdlc: remove checking of n_hdlcJiri Slaby1-29/+3
We got rid of backup_tty recently. Also, the tty layer ensures not to call other ldisc hooks after ldisc close. That means, all those tests are superfluous now so remove them. Note that we remove the magic check in write after schedule too. The tty cannot change during schedule. Signed-off-by: Jiri Slaby <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-02-21n_hdlc: remove cached ttyJiri Slaby1-16/+5
It's not needed, as now it's clear, that it's always the same as the one passed from the tty layer. Signed-off-by: Jiri Slaby <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
2020-02-21n_hdlc: inline n_hdlc_releaseJiri Slaby1-25/+10
Put the body of n_hdlc_release into the only caller. It can be seen, that the "if" is superfluous now -- the same happens few lines above in n_hdlc_tty_close already. So drop it. Drop also n_hdlc2tty macro as this was the only user. Signed-off-by: Jiri Slaby <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
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