From fe88c6489264eaea23570dfdf03e1d3f5f47f423 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Wed, 9 Sep 2020 16:31:00 +0200 Subject: [PATCH 1/4] serial: core: fix port-lock initialisation Commit f743061a85f5 ("serial: core: Initialise spin lock before use in uart_configure_port()") tried to work around a breakage introduced by commit a3cb39d258ef ("serial: core: Allow detach and attach serial device for console") by adding a second initialisation of the port lock when registering the port. As reported by the build robots [1], this doesn't really solve the regression introduced by the console-detach changes and also adds a second redundant initialisation of the lock for normal ports. Start cleaning up this mess by removing the redundant initialisation and making sure that the port lock is again initialised once-only for ports that aren't already in use as a console. [1] https://lore.kernel.org/r/20200802054852.GR23458@shao2-debian Fixes: f743061a85f5 ("serial: core: Initialise spin lock before use in uart_configure_port()") Fixes: a3cb39d258ef ("serial: core: Allow detach and attach serial device for console") Cc: stable # 5.7 Signed-off-by: Johan Hovold Reviewed-by: Andy Shevchenko Link: https://lore.kernel.org/r/20200909143101.15389-2-johan@kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/serial_core.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index f797c971cd82..53b79e1fcbc8 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -2378,13 +2378,6 @@ uart_configure_port(struct uart_driver *drv, struct uart_state *state, /* Power up port for set_mctrl() */ uart_change_pm(state, UART_PM_STATE_ON); - /* - * If this driver supports console, and it hasn't been - * successfully registered yet, initialise spin lock for it. - */ - if (port->cons && !(port->cons->flags & CON_ENABLED)) - __uart_port_spin_lock_init(port); - /* * Ensure that the modem control lines are de-activated. * keep the DTR setting that is set in uart_set_options() @@ -2900,7 +2893,12 @@ int uart_add_one_port(struct uart_driver *drv, struct uart_port *uport) goto out; } - uart_port_spin_lock_init(uport); + /* + * If this port is in use as a console then the spinlock is already + * initialised. + */ + if (!uart_console_enabled(uport)) + __uart_port_spin_lock_init(uport); if (uport->cons && uport->dev) of_console_check(uport->dev->of_node, uport->cons->name, uport->line); From e0830dbf71f191851ed3772d2760f007b7c5bc3a Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Wed, 9 Sep 2020 16:31:01 +0200 Subject: [PATCH 2/4] serial: core: fix console port-lock regression Fix the port-lock initialisation regression introduced by commit a3cb39d258ef ("serial: core: Allow detach and attach serial device for console") by making sure that the lock is again initialised during console setup. The console may be registered before the serial controller has been probed in which case the port lock needs to be initialised during console setup by a call to uart_set_options(). The console-detach changes introduced a regression in several drivers by effectively removing that initialisation by not initialising the lock when the port is used as a console (which is always the case during console setup). Add back the early lock initialisation and instead use a new console-reinit flag to handle the case where a console is being re-attached through sysfs. The question whether the console-detach interface should have been added in the first place is left for another discussion. Note that the console-enabled check in uart_set_options() is not redundant because of kgdboc, which can end up reinitialising an already enabled console (see commit 42b6a1baa3ec ("serial_core: Don't re-initialize a previously initialized spinlock.")). Fixes: a3cb39d258ef ("serial: core: Allow detach and attach serial device for console") Cc: stable # 5.7 Signed-off-by: Johan Hovold Reviewed-by: Andy Shevchenko Link: https://lore.kernel.org/r/20200909143101.15389-3-johan@kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/serial_core.c | 32 +++++++++++++++----------------- include/linux/serial_core.h | 1 + 2 files changed, 16 insertions(+), 17 deletions(-) diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 53b79e1fcbc8..124524ecfe26 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -1916,24 +1916,12 @@ static inline bool uart_console_enabled(struct uart_port *port) return uart_console(port) && (port->cons->flags & CON_ENABLED); } -static void __uart_port_spin_lock_init(struct uart_port *port) +static void uart_port_spin_lock_init(struct uart_port *port) { spin_lock_init(&port->lock); lockdep_set_class(&port->lock, &port_lock_key); } -/* - * Ensure that the serial console lock is initialised early. - * If this port is a console, then the spinlock is already initialised. - */ -static inline void uart_port_spin_lock_init(struct uart_port *port) -{ - if (uart_console(port)) - return; - - __uart_port_spin_lock_init(port); -} - #if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(CONFIG_CONSOLE_POLL) /** * uart_console_write - write a console message to a serial port @@ -2086,7 +2074,15 @@ uart_set_options(struct uart_port *port, struct console *co, struct ktermios termios; static struct ktermios dummy; - uart_port_spin_lock_init(port); + /* + * Ensure that the serial-console lock is initialised early. + * + * Note that the console-enabled check is needed because of kgdboc, + * which can end up calling uart_set_options() for an already enabled + * console via tty_find_polling_driver() and uart_poll_init(). + */ + if (!uart_console_enabled(port) && !port->console_reinit) + uart_port_spin_lock_init(port); memset(&termios, 0, sizeof(struct ktermios)); @@ -2794,10 +2790,12 @@ static ssize_t console_store(struct device *dev, if (oldconsole && !newconsole) { ret = unregister_console(uport->cons); } else if (!oldconsole && newconsole) { - if (uart_console(uport)) + if (uart_console(uport)) { + uport->console_reinit = 1; register_console(uport->cons); - else + } else { ret = -ENOENT; + } } } else { ret = -ENXIO; @@ -2898,7 +2896,7 @@ int uart_add_one_port(struct uart_driver *drv, struct uart_port *uport) * initialised. */ if (!uart_console_enabled(uport)) - __uart_port_spin_lock_init(uport); + uart_port_spin_lock_init(uport); if (uport->cons && uport->dev) of_console_check(uport->dev->of_node, uport->cons->name, uport->line); diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index 01fc4d9c9c54..8a99279a579b 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -248,6 +248,7 @@ struct uart_port { unsigned char hub6; /* this should be in the 8250 driver */ unsigned char suspended; + unsigned char console_reinit; const char *name; /* port name */ struct attribute_group *attr_group; /* port specific attributes */ const struct attribute_group **tty_groups; /* all attributes (serial core use only) */ From 3c5a87be170aba8ac40982182f812dcff6ed1ad1 Mon Sep 17 00:00:00 2001 From: Tobias Diedrich Date: Mon, 14 Sep 2020 19:36:28 +0200 Subject: [PATCH 3/4] serial: 8250_pci: Add Realtek 816a and 816b These serial ports are exposed by the OOB-management-engine on RealManage-enabled network cards (e.g. AMD DASH enabled systems using Realtek cards). Because these have 3 BARs, they fail the "num_iomem <= 1" check in serial_pci_guess_board. I've manually checked the two IOMEM regions and BAR 2 doesn't seem to respond to reads, but BAR 4 seems to be an MMIO version of the IO ports (untested). With this change, the ports are detected: 0000:02:00.1: ttyS0 at I/O 0x2200 (irq = 82, base_baud = 115200) is a 16550A 0000:02:00.2: ttyS1 at I/O 0x2100 (irq = 55, base_baud = 115200) is a 16550A lspci output: 02:00.1 0700: 10ec:816a (rev 0e) (prog-if 02 [16550]) Subsystem: 17aa:5082 Control: I/O+ Mem+ BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx- Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort+ SERR- Cc: stable Link: https://lore.kernel.org/r/20200914173628.GA22508@yamamaya.is-a-geek.org Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250_pci.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c index 3eb2d485eaeb..55bb7b897d97 100644 --- a/drivers/tty/serial/8250/8250_pci.c +++ b/drivers/tty/serial/8250/8250_pci.c @@ -5566,6 +5566,17 @@ static const struct pci_device_id serial_pci_tbl[] = { PCI_ANY_ID, PCI_ANY_ID, 0, 0, pbn_wch384_4 }, + /* + * Realtek RealManage + */ + { PCI_VENDOR_ID_REALTEK, 0x816a, + PCI_ANY_ID, PCI_ANY_ID, + 0, 0, pbn_b0_1_115200 }, + + { PCI_VENDOR_ID_REALTEK, 0x816b, + PCI_ANY_ID, PCI_ANY_ID, + 0, 0, pbn_b0_1_115200 }, + /* Fintek PCI serial cards */ { PCI_DEVICE(0x1c29, 0x1104), .driver_data = pbn_fintek_4 }, { PCI_DEVICE(0x1c29, 0x1108), .driver_data = pbn_fintek_8 }, From ec0972adecb391a8d8650832263a4790f3bfb4df Mon Sep 17 00:00:00 2001 From: Tetsuo Handa Date: Fri, 11 Sep 2020 07:57:06 +0900 Subject: [PATCH 4/4] fbcon: Fix user font detection test at fbcon_resize(). syzbot is reporting OOB read at fbcon_resize() [1], for commit 39b3cffb8cf31117 ("fbcon: prevent user font height or width change from causing potential out-of-bounds access") is by error using registered_fb[con2fb_map[vc->vc_num]]->fbcon_par->p->userfont (which was set to non-zero) instead of fb_display[vc->vc_num].userfont (which remains zero for that display). We could remove tricky userfont flag [2], for we can determine it by comparing address of the font data and addresses of built-in font data. But since that commit is failing to fix the original OOB read [3], this patch keeps the change minimal in case we decide to revert altogether. [1] https://syzkaller.appspot.com/bug?id=ebcbbb6576958a496500fee9cf7aa83ea00b5920 [2] https://syzkaller.appspot.com/text?tag=Patch&x=14030853900000 [3] https://syzkaller.appspot.com/bug?id=6fba8c186d97cf1011ab17660e633b1cc4e080c9 Reported-by: syzbot Signed-off-by: Tetsuo Handa Fixes: 39b3cffb8cf31117 ("fbcon: prevent user font height or width change from causing potential out-of-bounds access") Cc: George Kennedy Link: https://lore.kernel.org/r/f6e3e611-8704-1263-d163-f52c906a4f06@I-love.SAKURA.ne.jp Signed-off-by: Greg Kroah-Hartman --- drivers/video/fbdev/core/fbcon.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c index 66167830fefd..dae7ae7f225a 100644 --- a/drivers/video/fbdev/core/fbcon.c +++ b/drivers/video/fbdev/core/fbcon.c @@ -2203,7 +2203,7 @@ static int fbcon_resize(struct vc_data *vc, unsigned int width, struct fb_var_screeninfo var = info->var; int x_diff, y_diff, virt_w, virt_h, virt_fw, virt_fh; - if (ops->p && ops->p->userfont && FNTSIZE(vc->vc_font.data)) { + if (p->userfont && FNTSIZE(vc->vc_font.data)) { int size; int pitch = PITCH(vc->vc_font.width);