/* * USB Serial Console driver * * Copyright (C) 2001 - 2002 Greg Kroah-Hartman (greg@kroah.com) * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License version * 2 as published by the Free Software Foundation. * * Thanks to Randy Dunlap for the original version of this code. * */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #include #include #include #include #include #include struct usbcons_info { int magic; int break_flag; struct usb_serial_port *port; }; static struct usbcons_info usbcons_info; static struct console usbcons; /* * ------------------------------------------------------------ * USB Serial console driver * * Much of the code here is copied from drivers/char/serial.c * and implements a phony serial console in the same way that * serial.c does so that in case some software queries it, * it will get the same results. * * Things that are different from the way the serial port code * does things, is that we call the lower level usb-serial * driver code to initialize the device, and we set the initial * console speeds based on the command line arguments. * ------------------------------------------------------------ */ static const struct tty_operations usb_console_fake_tty_ops = { }; /* * The parsing of the command line works exactly like the * serial.c code, except that the specifier is "ttyUSB" instead * of "ttyS". */ static int usb_console_setup(struct console *co, char *options) { struct usbcons_info *info = &usbcons_info; int baud = 9600; int bits = 8; int parity = 'n'; int doflow = 0; int cflag = CREAD | HUPCL | CLOCAL; char *s; struct usb_serial *serial; struct usb_serial_port *port; int retval; struct tty_struct *tty = NULL; struct ktermios dummy; if (options) { baud = simple_strtoul(options, NULL, 10); s = options; while (*s >= '0' && *s <= '9') s++; if (*s) parity = *s++; if (*s) bits = *s++ - '0'; if (*s) doflow = (*s++ == 'r'); } /* Sane default */ if (baud == 0) baud = 9600; switch (bits) { case 7: cflag |= CS7; break; default: case 8: cflag |= CS8; break; } switch (parity) { case 'o': case 'O': cflag |= PARODD; break; case 'e': case 'E': cflag |= PARENB; break; } co->cflag = cflag; /* * no need to check the index here: if the index is wrong, console * code won't call us */ port = usb_serial_port_get_by_minor(co->index); if (port == NULL) { /* no device is connected yet, sorry :( */ pr_err("No USB device connected to ttyUSB%i\n", co->index); return -ENODEV; } serial = port->serial; retval = usb_autopm_get_interface(serial->interface); if (retval) goto error_get_interface; tty_port_tty_set(&port->port, NULL); info->port = port; ++port->port.count; if (!tty_port_initialized(&port->port)) { if (serial->type->set_termios) { /* * allocate a fake tty so the driver can initialize * the termios structure, then later call set_termios to * configure according to command line arguments */ tty = kzalloc(sizeof(*tty), GFP_KERNEL); if (!tty) { retval = -ENOMEM; goto reset_open_count; } kref_init(&tty->kref); tty->driver = usb_serial_tty_driver; tty->index = co->index; init_ldsem(&tty->ldisc_sem); INIT_LIST_HEAD(&tty->tty_files); kref_get(&tty->driver->kref); __module_get(tty->driver->owner); tty->ops = &usb_console_fake_tty_ops; tty_init_termios(tty); tty_port_tty_set(&port->port, tty); } /* only call the device specific open if this * is the first time the port is opened */ retval = serial->type->open(NULL, port); if (retval) { dev_err(&port->dev, "could not open USB console port\n"); goto fail; } if (serial->type->set_termios) { tty->termios.c_cflag = cflag; tty_termios_encode_baud_rate(&tty->termios, baud, baud); memset(&dummy, 0, sizeof(struct ktermios)); serial->type->set_termios(tty, port, &dummy); tty_port_tty_set(&port->port, NULL); tty_kref_put(tty); } tty_port_set_initialized(&port->port, 1); } /* Now that any required fake tty operations are completed restore * the tty port count */ --port->port.count; /* The console is special in terms of closing the device so * indicate this port is now acting as a system console. */ port->port.console = 1; mutex_unlock(&serial->disc_mutex); return retval; fail: tty_port_tty_set(&port->port, NULL); tty_kref_put(tty); reset_open_count: port->port.count = 0; usb_autopm_put_interface(serial->interface); error_get_interface: usb_serial_put(serial); mutex_unlock(&serial->disc_mutex); return retval; } static void usb_console_write(struct console *co, const char *buf, unsigned count) { static struct usbcons_info *info = &usbcons_info; struct usb_serial_port *port = info->port; struct usb_serial *serial; int retval = -ENODEV; if (!port || port->serial->dev->state == USB_STATE_NOTATTACHED) return; serial = port->serial; if (count == 0) return; dev_dbg(&port->dev, "%s - %d byte(s)\n", __func__, count); if (!port->port.console) { dev_dbg(&port->dev, "%s - port not opened\n", __func__); return; } while (count) { unsigned int i; unsigned int lf; /* search for LF so we can insert CR if necessary */ for (i = 0, lf = 0 ; i < count ; i++) { if (*(buf + i) == 10) { lf = 1; i++; break; } } /* pass on to the driver specific version of this function if it is available */ retval = serial->type->write(NULL, port, buf, i); dev_dbg(&port->dev, "%s - write: %d\n", __func__, retval); if (lf) { /* append CR after LF */ unsigned char cr = 13; retval = serial->type->write(NULL, port, &cr, 1); dev_dbg(&port->dev, "%s - write cr: %d\n", __func__, retval); } buf += i; count -= i; } } static struct tty_driver *usb_console_device(struct console *co, int *index) { struct tty_driver **p = (struct tty_driver **)co->data; if (!*p) return NULL; *index = co->index; return *p; } static struct console usbcons = { .name = "ttyUSB", .write = usb_console_write, .device = usb_console_device, .setup = usb_console_setup, .flags = CON_PRINTBUFFER, .index = -1, .data = &usb_serial_tty_driver, }; void usb_serial_console_disconnect(struct usb_serial *serial) { if (serial && serial->port && serial->port[0] && serial->port[0] == usbcons_info.port) { usb_serial_console_exit(); usb_serial_put(serial); } } void usb_serial_console_init(int minor) { if (minor == 0) { /* * Call register_console() if this is the first device plugged * in. If we call it earlier, then the callback to * console_setup() will fail, as there is not a device seen by * the USB subsystem yet. */ /* * Register console. * NOTES: * console_setup() is called (back) immediately (from * register_console). console_write() is called immediately * from register_console iff CON_PRINTBUFFER is set in flags. */ pr_debug("registering the USB serial console.\n"); register_console(&usbcons); } } void usb_serial_console_exit(void) { if (usbcons_info.port) { unregister_console(&usbcons); usbcons_info.port->port.console = 0; usbcons_info.port = NULL; } } ace to *always* immediately cancel all firmware fallback mechanism requests (Debian), they have: $ cat /lib/udev/rules.d/50-firmware.rules # stub for immediately telling the kernel that userspace firmware loading # failed; necessary to avoid long timeouts with CONFIG_FW_LOADER_USER_HELPER=y SUBSYSTEM=="firmware", ACTION=="add", ATTR{loading}="-1 Distributions with this udev rule would run into this crash only if the fallback mechanism is used. Since most distributions disable by default using the fallback mechanism (CONFIG_FW_LOADER_USER_HELPER_FALLBACK), this would typicaly mean only 2 drivers which *require* the fallback mechanism could typically incur a crash: drivers/firmware/dell_rbu.c and the drivers/leds/leds-lp55xx-common.c driver. Distributions enabling CONFIG_FW_LOADER_USER_HELPER_FALLBACK by default are obviously more exposed to this crash. The crash happens because after commit 5b029624948d ("firmware: do not use fw_lock for fw_state protection") and subsequent fix commit 5d47ec02c37ea6 ("firmware: Correct handling of fw_state_wait() return value") a race can happen between this cancelation and the firmware fw_state_wait_timeout() being woken up after a state change with which fw_load_abort() as that calls swake_up(). Upon error fw_state_wait_timeout() will also again call fw_load_abort() and trigger a null reference. At first glance we could just fix this with a !buf check on fw_load_abort() before accessing buf->fw_st, however there is a logical issue in having a state machine used for the fallback mechanism and preventing access from it once we abort as its inside the buf (buf->fw_st). The firmware_class.c code is setting the buf to NULL to annotate an abort has occurred. Replace this mechanism by simply using the state check instead. All the other code in place already uses similar checks for aborting as well so no further changes are needed. An oops can be reproduced with the new fw_fallback.sh fallback mechanism cancellation test. Either cancelling the fallback mechanism or the custom fallback mechanism triggers a crash. mcgrof@piggy ~/linux-next/tools/testing/selftests/firmware (git::20170111-fw-fixes)$ sudo ./fw_fallback.sh ./fw_fallback.sh: timeout works ./fw_fallback.sh: firmware comparison works ./fw_fallback.sh: fallback mechanism works [ this then sits here when it is trying the cancellation test ] Kernel log: test_firmware: loading 'nope-test-firmware.bin' misc test_firmware: Direct firmware load for nope-test-firmware.bin failed with error -2 misc test_firmware: Falling back to user helper BUG: unable to handle kernel NULL pointer dereference at 0000000000000038 IP: _request_firmware+0xa27/0xad0 PGD 0 Oops: 0000 [#1] SMP Modules linked in: test_firmware(E) ... etc ... CPU: 1 PID: 1396 Comm: fw_fallback.sh Tainted: G W E 4.10.0-rc3-next-20170111+ #30 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.1-0-g8891697-prebuilt.qemu-project.org 04/01/2014 task: ffff9740b27f4340 task.stack: ffffbb15c0bc8000 RIP: 0010:_request_firmware+0xa27/0xad0 RSP: 0018:ffffbb15c0bcbd10 EFLAGS: 00010246 RAX: 00000000fffffffe RBX: ffff9740afe5aa80 RCX: 0000000000000000 RDX: ffff9740b27f4340 RSI: 0000000000000283 RDI: 0000000000000000 RBP: ffffbb15c0bcbd90 R08: ffffbb15c0bcbcd8 R09: 0000000000000000 R10: 0000000894a0d4b1 R11: 000000000000008c R12: ffffffffc0312480 R13: 0000000000000005 R14: ffff9740b1c32400 R15: 00000000000003e8 FS: 00007f8604422700(0000) GS:ffff9740bfc80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000038 CR3: 000000012164c000 CR4: 00000000000006e0 Call Trace: request_firmware+0x37/0x50 trigger_request_store+0x79/0xd0 [test_firmware] dev_attr_store+0x18/0x30 sysfs_kf_write+0x37/0x40 kernfs_fop_write+0x110/0x1a0 __vfs_write+0x37/0x160 ? _cond_resched+0x1a/0x50 vfs_write+0xb5/0x1a0 SyS_write+0x55/0xc0 ? trace_do_page_fault+0x37/0xd0 entry_SYSCALL_64_fastpath+0x1e/0xad RIP: 0033:0x7f8603f49620 RSP: 002b:00007fff6287b788 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000055c307b110a0 RCX: 00007f8603f49620 RDX: 0000000000000016 RSI: 000055c3084d8a90 RDI: 0000000000000001 RBP: 0000000000000016 R08: 000000000000c0ff R09: 000055c3084d6336 R10: 000055c307b108b0 R11: 0000000000000246 R12: 000055c307b13c80 R13: 000055c3084d6320 R14: 0000000000000000 R15: 00007fff6287b950 Code: 9f 64 84 e8 9c 61 fe ff b8 f4 ff ff ff e9 6b f9 ff ff 48 c7 c7 40 6b 8d 84 89 45 a8 e8 43 84 18 00 49 8b be 00 03 00 00 8b 45 a8 <83> 7f 38 02 74 08 e8 6e ec ff ff 8b 45 a8 49 c7 86 00 03 00 00 RIP: _request_firmware+0xa27/0xad0 RSP: ffffbb15c0bcbd10 CR2: 0000000000000038 ---[ end trace 6d94ac339c133e6f ]--- Fixes: 5d47ec02c37e ("firmware: Correct handling of fw_state_wait() return value") Reported-and-Tested-by: Jakub Kicinski <jakub.kicinski@netronome.com> Reported-and-Tested-by: Patrick Bruenn <p.bruenn@beckhoff.com> Reported-by: Chris Wilson <chris@chris-wilson.co.uk> CC: <stable@vger.kernel.org> [3.10+] Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/btrfs/tests/extent-buffer-tests.c')