kernel/drivers/tty, branch linux-2.6.39.y

TTY: ldisc, do not close until there are readers

2011-07-09T06:15:07Z

commit 92f6fa09bd453ffe3351fa1f1377a1b7cfa911e6 upstream. We restored tty_ldisc_wait_idle in 100eeae2c5c (TTY: restore tty_ldisc_wait_idle). We used it in the ldisc changing path to fix the case where there are tasks in n_tty_read waiting for data and somebody tries to change ldisc. Similar to the case above, there may be also tasks waiting in n_tty_read while hangup is performed. As 65b770468e98 (tty-ldisc: turn ldisc user count into a proper refcount) removed the wait-until-idle from all paths, hangup path won't wait for them to disappear either now. So add it back even to the hangup path. There is a difference, we need uninterruptible sleep as there is obviously HUP signal pending. So tty_ldisc_wait_idle now sleeps without possibility to be interrupted. This is what original tty_ldisc_wait_idle did. After the wait idle reintroduction (100eeae2c5c), we have had interruptible sleeps for the ldisc changing path. But as there is a 5s timeout anyway, we don't allow it to be interrupted from now on. It's not worth the added complexity of deciding what kind of sleep we want. Before 65b770468e98 tty_ldisc_release was called also from tty_ldisc_release. It is called from tty_release, so I don't think we need to restore that one. This is nicely reproducible after constifying the timing when drivers/tty/n_tty.c is patched as follows ("TTY: ntty, add one more sanity check" patch is needed to actually see it explode): %% -1548,6 +1549,7 @@ static int n_tty_open(struct tty_struct *tty) /* These are ugly. Currently a malloc failure here can panic */ if (!tty->read_buf) { + msleep(100); tty->read_buf = kzalloc(N_TTY_BUF_SIZE, GFP_KERNEL); if (!tty->read_buf) return -ENOMEM; %% -1785,6 +1788,7 @@ do_it_again: break; } timeout = schedule_timeout(timeout); + msleep(20); continue; } __set_current_state(TASK_RUNNING); ===== With a process: ===== while (1) { int fd = open(argv[1], O_RDWR); read(fd, buf, sizeof(buf)); close(fd); } ===== and its child: ===== setsid(); while (1) { int fd = open(tty, O_RDWR|O_NOCTTY); ioctl(fd, TIOCSCTTY, 1); vhangup(); close(fd); usleep(100 * (10 + random() % 1000)); } ===== EOF ===== References: https://bugzilla.novell.com/show_bug.cgi?id=693374 References: https://bugzilla.novell.com/show_bug.cgi?id=694509 Signed-off-by: Jiri Slaby Cc: Alan Cox Cc: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

ARM: SAMSUNG: serial: Fix on handling of one clock source for UART

2011-07-09T06:15:06Z

commit 470f22975448a65a1084a6f0721fa5df15323f02 upstream. This patch fixes the way of comparison for handling of two or more clock sources for UART. For example, if just only one clock source is defined even though there are two clock sources for UART, the serial driver does not set proper clock up. Of course, it is problem. So this patch changes the condition of comparison to avoid useless setup clock and adds a flag 'NO_NEED_CHECK_CLKSRC' which means selection of source clock is not required. In addition, since the Exynos4210 has only one clock source for UART this patch adds the flag into its common_init_uarts(). Signed-off-by: Boojin Kim Signed-off-by: Kukjin Kim Signed-off-by: Greg Kroah-Hartman

drivers/tty/serial/pch_uart.c: don't oops if dmi_get_system_info returns NULL

2011-07-09T06:14:57Z

commit fb139dfeef9558a12ffdbf9e26951fd1a9304f3b upstream. If dmi_get_system_info() returns NULL, pch_uart_init_port() will dereferencea a zero pointer. This oops was observed on an Atom based board which has no BIOS, but a bootloder which doesn't provide DMI data. Signed-off-by: Alexander Stein Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

serial: core, remove uart_update_termios

2011-06-23T22:05:34Z

commit 6f5c24ad0f7619502199185a026a228174a27e68 upstream. Now, uart_update_termios is empty, so it's time to remove it. We no longer need a live tty in .dtr_rts. So this should prune all the bugs where tty is zeroed in port->tty during tty_port_block_til_ready. There is one thing to note. We don't set ASYNC_NORMAL_ACTIVE now. It's because this is done already in tty_port_block_til_ready. Signed-off-by: Jiri Slaby Cc: Alan Cox Cc: Arnd Bergmann Signed-off-by: Greg Kroah-Hartman

serial: core, do not set DTR/RTS twice on startup

2011-06-23T22:05:34Z

commit 303a7a1199c20f7c9452f024a6e17bf348b6b398 upstream. In .dtr_rts we do: uart_set_mctrl(uport, TIOCM_DTR | TIOCM_RTS) and call uart_update_termios. It does: uart_set_mctrl(port, TIOCM_DTR | TIOCM_RTS) once again. As the only callsite of uart_update_termios is .dtr_rts, remove the uart_set_mctrl from uart_update_termios to not set it twice. Signed-off-by: Jiri Slaby Cc: Alan Cox Cc: Arnd Bergmann Signed-off-by: Greg Kroah-Hartman

serial: core, move termios handling to uart_startup

2011-06-23T22:05:33Z

commit c7d7abff40c27f82fe78b1091ab3fad69b2546f9 upstream. We should not fiddle with speed and cflags in .dtr_rts hook. Actually we might not have tty at that moment already. So move the console cflag copy and speed setup into uart_startup. Actually the speed setup is already there, but we need to call it unconditionally (uart_startup is called from uart_open with hw_init = 0). This means we move uart_change_speed before dtr/rts setup in .dtr_rts. But this should not matter as the setup should be called after uart_change_speed anyway. Before: After: dtr/rts setup (dtr_rts) uart_change_speed (startup) uart_change_speed (update_termios) dtr/rts setup (dtr_rts) dtr/rts setup (update_termios) dtr/rts setup (update_termios) The second setup will dismiss with the next patch. Signed-off-by: Jiri Slaby Cc: Alan Cox Cc: Arnd Bergmann Signed-off-by: Greg Kroah-Hartman

drivercore: revert addition of of_match to struct device

2011-05-18T18:32:23Z

Commit b826291c, "drivercore/dt: add a match table pointer to struct device" added an of_match pointer to struct device to cache the of_match_table entry discovered at driver match time. This was unsafe because matching is not an atomic operation with probing a driver. If two or more drivers are attempted to be matched to a driver at the same time, then the cached matching entry pointer could get overwritten. This patch reverts the of_match cache pointer and reworks all users to call of_match_device() directly instead. Signed-off-by: Grant Likely

tty/n_gsm: fix bug in CRC calculation for gsm1 mode

2011-04-19T23:38:50Z

Problem description: gsm_queue() calculate a CRC for arrived frames. As a last step of CRC calculation it call gsm->fcs = gsm_fcs_add(gsm->fcs, gsm->received_fcs); This work perfectly for the case of GSM0 mode as gsm->received_fcs contain the last piece of data required to generate final CRC. gsm->received_fcs is not used for GSM1 mode. Thus we put an additional byte to CRC calculation. As result we get a wrong CRC and reject incoming frame. Signed-off-by: Mikhail Kshevetskiy Acked-by: Alan Cox Cc: stable Signed-off-by: Greg Kroah-Hartman

serial/imx: read cts state only after acking cts change irq

2011-04-19T23:36:25Z

If cts changes between reading the level at the cts input (USR1_RTSS) and acking the irq (USR1_RTSD) the last edge doesn't generate an irq and uart_handle_cts_change is called with a outdated value for cts. The race was introduced by commit ceca629 ([ARM] 2971/1: i.MX uart handle rts irq) Reported-by: Arwed Springer Tested-by: Arwed Springer Cc: stable@kernel.org # 2.6.14+ Signed-off-by: Uwe Kleine-König Signed-off-by: Greg Kroah-Hartman

Merge branch 'sh-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6

2011-04-07T19:48:45Z

* 'sh-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6: sh: select ARCH_NO_SYSDEV_OPS. sh: fix build error in board-sh7757lcr.c sh: landisk: Remove whitespace sh: landisk: Remove mv_nr_irqs sh: sh-sci: Fix double initialization by serial_console_setup serial: sh-sci: prevent setup of uninitialized serial console dma: shdma: add checking the DMAOR_AE in sh_dmae_err