The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable@xxxxxxxxxxxxxxx>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-4.19.y git checkout FETCH_HEAD git cherry-pick -x 8a1060ce974919f2a79807527ad82ac39336eda2 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable@xxxxxxxxxxxxxxx>' --in-reply-to '2024012653-unframed-creation-e7d8@gregkh' --subject-prefix 'PATCH 4.19.y' HEAD^.. Possible dependencies: 8a1060ce9749 ("serial: sc16is7xx: fix invalid sc16is7xx_lines bitfield in case of probe error") 4409df5866b7 ("serial: sc16is7xx: change EFR lock to operate on each channels") 41a308cbedb2 ("serial: sc16is7xx: remove unused line structure member") 3837a0379533 ("serial: sc16is7xx: improve regmap debugfs by using one regmap per port") b4a778303ea0 ("serial: sc16is7xx: add missing support for rs485 devicetree properties") 049994292834 ("serial: sc16is7xx: fix regression with GPIO configuration") dabc54a45711 ("serial: sc16is7xx: remove obsolete out_thread label") c8f71b49ee4d ("serial: sc16is7xx: setup GPIO controller later in probe") 267913ecf737 ("serial: sc16is7xx: Fill in rs485_supported") 21144bab4f11 ("sc16is7xx: Handle modem status lines") cc4c1d05eb10 ("sc16is7xx: Properly resume TX after stop") d4ab5487cc77 ("Merge 5.17-rc6 into tty-next") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 8a1060ce974919f2a79807527ad82ac39336eda2 Mon Sep 17 00:00:00 2001 From: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx> Date: Thu, 21 Dec 2023 18:18:08 -0500 Subject: [PATCH] serial: sc16is7xx: fix invalid sc16is7xx_lines bitfield in case of probe error If an error occurs during probing, the sc16is7xx_lines bitfield may be left in a state that doesn't represent the correct state of lines allocation. For example, in a system with two SC16 devices, if an error occurs only during probing of channel (port) B of the second device, sc16is7xx_lines final state will be 00001011b instead of the expected 00000011b. This is caused in part because of the "i--" in the for/loop located in the out_ports: error path. Fix this by checking the return value of uart_add_one_port() and set line allocation bit only if this was successful. This allows the refactor of the obfuscated for(i--...) loop in the error path, and properly call uart_remove_one_port() only when needed, and properly unset line allocation bits. Also use same mechanism in remove() when calling uart_remove_one_port(). Fixes: c64349722d14 ("sc16is7xx: support multiple devices") Cc: <stable@xxxxxxxxxxxxxxx> Cc: Yury Norov <yury.norov@xxxxxxxxx> Signed-off-by: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx> Link: https://lore.kernel.org/r/20231221231823.2327894-2-hugo@xxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c index e40e4a99277e..17b90f971f96 100644 --- a/drivers/tty/serial/sc16is7xx.c +++ b/drivers/tty/serial/sc16is7xx.c @@ -407,19 +407,6 @@ static void sc16is7xx_port_update(struct uart_port *port, u8 reg, regmap_update_bits(one->regmap, reg, mask, val); } -static int sc16is7xx_alloc_line(void) -{ - int i; - - BUILD_BUG_ON(SC16IS7XX_MAX_DEVS > BITS_PER_LONG); - - for (i = 0; i < SC16IS7XX_MAX_DEVS; i++) - if (!test_and_set_bit(i, &sc16is7xx_lines)) - break; - - return i; -} - static void sc16is7xx_power(struct uart_port *port, int on) { sc16is7xx_port_update(port, SC16IS7XX_IER_REG, @@ -1550,6 +1537,13 @@ static int sc16is7xx_probe(struct device *dev, SC16IS7XX_IOCONTROL_SRESET_BIT); for (i = 0; i < devtype->nr_uart; ++i) { + s->p[i].port.line = find_first_zero_bit(&sc16is7xx_lines, + SC16IS7XX_MAX_DEVS); + if (s->p[i].port.line >= SC16IS7XX_MAX_DEVS) { + ret = -ERANGE; + goto out_ports; + } + /* Initialize port data */ s->p[i].port.dev = dev; s->p[i].port.irq = irq; @@ -1569,14 +1563,8 @@ static int sc16is7xx_probe(struct device *dev, s->p[i].port.rs485_supported = sc16is7xx_rs485_supported; s->p[i].port.ops = &sc16is7xx_ops; s->p[i].old_mctrl = 0; - s->p[i].port.line = sc16is7xx_alloc_line(); s->p[i].regmap = regmaps[i]; - if (s->p[i].port.line >= SC16IS7XX_MAX_DEVS) { - ret = -ENOMEM; - goto out_ports; - } - mutex_init(&s->p[i].efr_lock); ret = uart_get_rs485_mode(&s->p[i].port); @@ -1594,8 +1582,13 @@ static int sc16is7xx_probe(struct device *dev, kthread_init_work(&s->p[i].tx_work, sc16is7xx_tx_proc); kthread_init_work(&s->p[i].reg_work, sc16is7xx_reg_proc); kthread_init_delayed_work(&s->p[i].ms_work, sc16is7xx_ms_proc); + /* Register port */ - uart_add_one_port(&sc16is7xx_uart, &s->p[i].port); + ret = uart_add_one_port(&sc16is7xx_uart, &s->p[i].port); + if (ret) + goto out_ports; + + set_bit(s->p[i].port.line, &sc16is7xx_lines); /* Enable EFR */ sc16is7xx_port_write(&s->p[i].port, SC16IS7XX_LCR_REG, @@ -1653,10 +1646,9 @@ static int sc16is7xx_probe(struct device *dev, #endif out_ports: - for (i--; i >= 0; i--) { - uart_remove_one_port(&sc16is7xx_uart, &s->p[i].port); - clear_bit(s->p[i].port.line, &sc16is7xx_lines); - } + for (i = 0; i < devtype->nr_uart; i++) + if (test_and_clear_bit(s->p[i].port.line, &sc16is7xx_lines)) + uart_remove_one_port(&sc16is7xx_uart, &s->p[i].port); kthread_stop(s->kworker_task); @@ -1678,8 +1670,8 @@ static void sc16is7xx_remove(struct device *dev) for (i = 0; i < s->devtype->nr_uart; i++) { kthread_cancel_delayed_work_sync(&s->p[i].ms_work); - uart_remove_one_port(&sc16is7xx_uart, &s->p[i].port); - clear_bit(s->p[i].port.line, &sc16is7xx_lines); + if (test_and_clear_bit(s->p[i].port.line, &sc16is7xx_lines)) + uart_remove_one_port(&sc16is7xx_uart, &s->p[i].port); sc16is7xx_power(&s->p[i].port, 0); }
