Commits · 584abc3775e76c1a2abe725355915851ed23ed6c · Kirill Smelkov / linux

11 Dec, 2009 30 commits

tty: sdio_uart: Switch to the open/close helpers · 584abc37

Alan Cox authored Nov 30, 2009

Gets us proper tty semantics, removes some code and fixes up a few corner
case races (hangup during open etc)
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

584abc37

sdio_uart: Move the open lock · 0a68f64f

Alan Cox authored Nov 05, 2009

When we move to the tty_port logic the port mutex will protect open v close
v hangup. Move to this first in the existing open code so we have a bisection
point.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

0a68f64f

sdio_uart: refcount the tty objects · 530646f4

Alan Cox authored Nov 05, 2009

The tty can go away underneath us, so we must refcount it. Do the naïve
implementation initially. We will worry about startup shortly.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

530646f4

sdio_uart: Fix oops caused by the previous changeset · 0395b48c

Nicolas Pitre authored Nov 05, 2009

Now... testing reveals that the very first patch "sdio_uart: use
tty_port" causes a segmentation fault in sdio_uart_open():

Unable to handle kernel NULL pointer dereference at virtual address 00000084
pgd = dfb44000 [00000084] *pgd=1fb99031, *pte=00000000, *ppte=00000000
Internal error: Oops: 17 [#1] PREEMPT
last sysfs file:
/sys/devices/platform/mvsdio/mmc_host/mmc0/mmc0:f111/uevent
Modules linked in:
CPU: 0    Not tainted  (2.6.32-rc5-next-20091102-00001-gb36eae9 #10)
PC is at sdio_uart_open+0x204/0x2cc
[...]
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

0395b48c

sdio_uart: use tty_port · b5849b1a

Alan Cox authored Nov 05, 2009

Add a tty_port object to the sdio uart. For the moment just begin using the
tty field of the port, as this is the critical one to clean up.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

b5849b1a

tty_port: Move hupcl handling · e707c35c

Alan Cox authored Nov 05, 2009

Move the HUCPL handling from the end of close_port_start to the beginning
of close_port_end. What this actually does is change the ordering from

	port shutdown
	port->dtr_rts

to

	port->dtr_rts
	port shutdown

Some hardware drops the physical connection on shutdown so we must perform
the port operations before the shutdown.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

e707c35c

devpts_get_tty() should validate inode · edfacdd6

Sukadev Bhattiprolu authored Nov 17, 2009

devpts_get_tty() assumes that the inode passed in is associated with a valid
pty.  But if the only reference to the pty is via a bind-mount, the inode
passed to devpts_get_tty() while valid, would refer to a pty that no longer
exists.

With a lot of debug effort, Grzegorz Nosek developed a small program (see
below) to reproduce a crash on recent kernels. This crash is a regression
introduced by the commit:

	commit 527b3e47
	Author: Sukadev Bhattiprolu <sukadev@us.ibm.com>
	Date:   Mon Oct 13 10:43:08 2008 +0100

To fix, ensure that the dentry associated with the inode has not yet been
deleted/unhashed by devpts_pty_kill().

See also:
https://lists.linux-foundation.org/pipermail/containers/2009-July/019273.html 

tty-bug.c:

#define _GNU_SOURCE
#include <fcntl.h>
#include <sched.h>
#include <stdlib.h>
#include <sys/mount.h>
#include <sys/signal.h>
#include <unistd.h>
#include <stdio.h>

#include <linux/fs.h>

void dummy(int sig)
{
}

static int child(void *unused)
{
	int fd;

	signal(SIGINT, dummy); signal(SIGHUP, dummy);
	pause(); /* cheesy synchronisation to wait for /dev/pts/0 to appear */

	mount("/dev/pts/0", "/dev/console", NULL, MS_BIND, NULL);
	sleep(2);

	fd = open("/dev/console", O_RDWR);
	dup(0); dup(0);
	write(1, "Hello world!\n", sizeof("Hello world!\n")-1);
	return 0;
}

int main(void)
{
	pid_t pid;
	char *stack;

	stack = malloc(16384);
	pid = clone(child, stack+16384, CLONE_NEWNS|SIGCHLD, NULL);

	open("/dev/ptmx", O_RDWR|O_NOCTTY|O_NONBLOCK);

	unlockpt(fd); grantpt(fd);

	sleep(2);
	kill(pid, SIGHUP);
	sleep(1);
	return 0; /* exit before child opens /dev/console */
}
Reported-by: Grzegorz Nosek <root@localdomain.pl>
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Tested-by: Serge Hallyn <serue@us.ibm.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

edfacdd6

Serial: Do not read IIR in serial8250_start_tx when UART_BUG_TXEN · 68cb4f8e

Ian Jackson authored Nov 18, 2009

Do not read IIR in serial8250_start_tx when UART_BUG_TXEN

Reading the IIR clears some oustanding interrupts so it is not safe.
Instead, simply transmit immediately if the buffer is empty without
regard to IIR.
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Jiri Kosina <jkosina@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

68cb4f8e

tty: docs: serial/tty, add to ldisc methods · 7e11a0fb

Tilman Schmidt authored Nov 04, 2009

A small addition to the ldisc method descriptions.
Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

7e11a0fb

Serial: pxa: work around Errata #75 · c934878c

Uwe Kleine-König authored Nov 06, 2009

Intel(R) PXA27x Processor Family Specification Update (Nov 2005)
says:

  E75. UART: Baud rate may not be programmed correctly on
       back-to-back writes.

  Problem:
  When programming the Divisor Latch registers, Low and High (DLL and
  DLH), with back-to-back writes, the second register write may not
  take effect. The result is an incorrect baud rate.

  Workaround:
  After programming the first Divisor Latch register, read and verify
  it before programming the second Divisor Latch register.

This was hit when changing the baud rate from 115200 to 9600 while
receiving characters at 9600 Bd.

And fixed indention of some comments nearby.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Cc: Eric Miao <eric.y.miao@gmail.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Mike Rapoport <mike@compulab.co.il>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

c934878c

serial, 8250: calculate irqflags bitmask before loop · 4c0ebb80

André Goddard Rosa authored Oct 25, 2009

Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

4c0ebb80

serial: cascade needless conditionals · 82cb7ba1

André Goddard Rosa authored Oct 25, 2009

Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

82cb7ba1

serial: fix NULL pointer dereference · 9e845abf

André Goddard Rosa authored Oct 25, 2009

If kzalloc() or alloc_tty_driver() fails, we call:
    put_tty_driver(normal = NULL).

Then:
    put_tty_driver -> tty_driver_kref_put -> kref_put(&NULL->kref, ...)
Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

9e845abf

opticon: Fix resume logic · 2a0785ea