Commit Graph

182 Commits

Author SHA1 Message Date
Alan Cox
1aa4bed82a tty: fix sanity check
The WARN_ON() that was added to tty_reopen can be triggered in the specific
case of a hangup occurring during a re-open of a tty which is not in the
middle of being otherwise closed.

In that case however the WARN() is bogus as we don't hold the neccessary
locks to make a correct decision.

The case we should be checking is "if the ldisc is not changing and reopen
is occuring". We could drop the WARN_ON but for the moment the debug is more
valuable even if it means taking a mutex as it will find any other cases.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-16 12:01:16 -07:00
Alan Cox
f2c4c65c83 tty: Move ldisc_flush
We have a tty_ldisc file now so put tty_ldisc_flush in the right place

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:01 -07:00
Alan Cox
c65c9bc3ef tty: rewrite the ldisc locking
There are several pretty much unfixable races in the old ldisc code, especially
with respect to pty behaviour and also to hangup. It's easier to rewrite the
code than simply try and patch it up.

This patch
- splits the ldisc from the tty (so we will be able to refcount it more cleanly
  later)
- introduces a mutex lock for ldisc changing on an active device
- fixes the complete mess that hangup caused
- implements hopefully correct setldisc/close/hangup locking

There are still some problems around pty pairs that have always been there but
at least it is now possible to understand the code and fix further problems.

This fixes the following known bugs
- hang up can leak ldisc references
- hang up may not call open/close on ldisc in a matched way
- pty/tty pairs can deadlock during an ldisc change
- reading the ldisc proc files can cause every ldisc to be loaded

and probably a few other of the mysterious ldisc race reports.

I'm sure it also adds the odd new one.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:01 -07:00
Alan Cox
e8b70e7d3e tty: Extract various bits of ldisc code
Before trying to tackle the ldisc bugs the code needs to be a good deal
more readable, so do the simple extractions of routines first.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:01 -07:00
Alan Cox
5f0878acba tty: Fix oops when scanning the polling list for kgdb
Costantino Leandro found a bug in tty_find_polling_driver and provided a
patch that fixed the crash but not the underlying bug. This fixes the
underlying bug where the list walk corrupts the values it is using on a
match but then reuses them if the open fails.

Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 08:51:01 -07:00
Oleg Nesterov
1b0f7ffd0e pids: kill signal_struct-> __pgrp/__session and friends
We are wasting 2 words in signal_struct without any reason to implement
task_pgrp_nr() and task_session_nr().

task_session_nr() has no callers since
2e2ba22ea4, we can remove it.

task_pgrp_nr() is still (I believe wrongly) used in fs/autofsX and
fs/coda.

This patch reimplements task_pgrp_nr() via task_pgrp_nr_ns(), and kills
__pgrp/__session and the related helpers.

The change in drivers/char/tty_io.c is cosmetic, but hopefully makes sense
anyway.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Alan Cox <number6@the-village.bc.nu>		[tty parts]
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:05:02 -07:00
Andrew Morton
846c151a4d __tty_open(): use the correct type for saved_flags
filp->f_flags is unsigned, so use that type for the local copy.

Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:04:48 -07:00
Davide Libenzi
4b19449db0 epoll keyed wakeups: make tty use keyed wakeups
Introduce keyed event wakeups inside the TTY code.

Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Miller <davem@davemloft.net>
Cc: William Lee Irwin III <wli@movementarian.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-01 08:59:21 -07:00
Jonathan Corbet
db1dd4d376 Use f_lock to protect f_flags
Traditionally, changes to struct file->f_flags have been done under BKL
protection, or with no protection at all.  This patch causes all f_flags
changes after file open/creation time to be done under protection of
f_lock.  This allows the removal of some BKL usage and fixes a number of
longstanding (if microscopic) races.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2009-03-16 08:32:27 -06:00
Eric Paris
808ffa3d30 tty_open can return to userspace holding tty_mutex
__tty_open could return (to userspace) holding the tty_mutex thanks to a
regression introduced by 4a2b5fddd5 ("Move
tty lookup/reopen to caller").

This was found by bisecting an fsfuzzer problem.  Admittedly I have no
idea how it managed to tickle this 100% reliably, but it is clearly a
regression and when hit leaves the box in a completely unusable state.
This patch lets the fsfuzzer test complete every time.

Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-27 07:37:15 -08:00
Alan Cox
fc6f623822 pty: simplify resize
We have special case logic for resizing pty/tty pairs. We also have a per
driver resize method so for the pty case we should use it.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-02 10:19:36 -08:00
Jason Wessel
a47d545f57 tty: Fix sparse static warning for tty_driver_lookup_tty
Fixed sparse warning:
drivers/char/tty_io.c:1216:19: warning: symbol 'tty_driver_lookup_tty' was not declared. Should it be static?

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-02 10:19:36 -08:00
Joe Peterson
a88a69c912 n_tty: Fix loss of echoed characters and remove bkl from n_tty
Fixes the loss of echoed (and other ldisc-generated characters) when
the tty is stopped or when the driver output buffer is full (happens
frequently for input during continuous program output, such as ^C)
and removes the Big Kernel Lock from the N_TTY line discipline.

Adds an "echo buffer" to the N_TTY line discipline that handles all
ldisc-generated output (including echoed characters).  Along with the
loss of characters, this also fixes the associated loss of sync between
tty output and the ldisc state when characters cannot be immediately
written to the tty driver.

The echo buffer stores (in addition to characters) state operations that need
to be done at the time of character output (like management of the column
position).  This allows echo to cooperate correctly with program output,
since the ldisc state remains consistent with actual characters written.

Since the echo buffer code now isolates the tty column state code
to the process_out* and process_echoes functions, we can remove the
Big Kernel Lock (BKL) and replace it with mutex locks.

Highlights are:

* Handles echo (and other ldisc output) when tty driver buffer is full
  - continuous program output can block echo
* Saves echo when tty is in stopped state (e.g. ^S)
  - (e.g.: ^Q will correctly cause held characters to be released for output)
* Control character pairs (e.g. "^C") are treated atomically and not
  split up by interleaved program output
* Line discipline state is kept consistent with characters sent to
  the tty driver
* Remove the big kernel lock (BKL) from N_TTY line discipline

Signed-off-by: Joe Peterson <joe@skyrush.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-02 10:19:35 -08:00
Al Viro
1e641743f0 Audit: Log TIOCSTI
AUDIT_TTY records currently log all data read by processes marked for
TTY input auditing, even if the data was "pushed back" using the TIOCSTI
ioctl, not typed by the user.

This patch records all TIOCSTI calls to disambiguate the input.  It
generates one audit message per character pushed back; considering
TIOCSTI is used very rarely, this simple solution is probably good
enough.  (The only program I could find that uses TIOCSTI is mailx/nail
in "header editing" mode, e.g. using the ~h escape.  mailx is used very
rarely, and the escapes are used even rarer.)

Signed-Off-By: Miloslav Trmac <mitr@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: James Morris <jmorris@namei.org>
2008-12-09 20:32:06 +11:00
Will Newton
296fa7f6a3 drivers/char/tty_io.c: Avoid panic when no console is configured.
When no console is configured tty_open tries to call kref_get on a NULL
pointer, return ENODEV instead.

Signed-off-by: Will Newton <will.newton@gmail.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-12-01 08:19:10 -08:00
Greg Kroah-Hartman
03457cd455 device create: char: convert device_create_drvdata to device_create
Now that device_create() has been audited, rename things back to the
original call to be sane.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-10-16 09:24:42 -07:00
Arjan van de Ven
7c3b1dcf13 tty: make sure that proc_clear_tty stores the cpu flags
proc_clear_tty() gets called with interrupts off (while holding the task list
lock) from sys_setid. This means that it needs the _irqsave version of the
locking primitives.

Reported-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Tested-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-15 10:19:51 -07:00
Jason Wessel
402fda9201 tty: tty_io.c shadows sparse fix
drivers/char/tty_io.c:1413:17: warning: symbol 'buf' shadows an earlier one
drivers/char/tty_io.c:1379:20: originally declared here

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-13 09:51:44 -07:00
Alan Cox
fe6e29fdb1 tty: simplify ktermios allocation
Copy the simplification from the pty unix98 special case to the generic one.
This allows us to kill off driver->termios_locked entirely which is nice. We
have to whack bits of the cris driver as it meddles in places it shouldn't
providing its own arrays that were never used anyway.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-13 09:51:44 -07:00
Sukadev Bhattiprolu
15f1a6338d Add an instance parameter devpts interfaces
Pass-in 'inode' or 'tty' parameter to devpts interfaces.  With multiple
devpts instances, these parameters will be used in subsequent patches
to identify the instance of devpts mounted. The parameters also help
simplify devpts implementation.

Changelog[v3]:
	- minor changes due to merge with ttydev updates
	- rename parameters to emphasize they are ptmx or pts inodes
	- pass-in tty_struct * to devpts_pty_kill() (this will help
	  cleanup the get_node() call in a subsequent patch)

Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-13 09:51:43 -07:00
Sukadev Bhattiprolu
4a2b5fddd5 Move tty lookup/reopen to caller
Move tty_driver_lookup_tty() and tty_reopen() from tty_init_dev()
into tty_open() (one of the two callers of tty_init_dev()).  These
calls are not really required in ptmx_open(), the other caller,
since ptmx_open() would be setting up a new tty.

Changelog[v2]:
	- remove the lookup and reopen calls from ptmx_open
	- merge with recent changes to ttydev tree

Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-13 09:51:43 -07:00
Alan Cox
bf970ee46e tty: extract the pty init time special cases
The majority of the remaining init_dev code is pty special cases. We
refactor this code into the driver->install method.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-13 09:51:43 -07:00
Alan Cox
73ec06fc5f tty: Finish fixing up the init_dev interface to use ERR_PTR
Original suggestion and proposal from Sukadev Bhattiprolu.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-13 09:51:43 -07:00
Alan Cox
8b0a88d591 tty: More driver operations
We have the lookup operation abstracted which is nice for pty cleanup but
we really want to abstract the add/remove entries as well so that we can
pull the pty code out of the tty core and create a clear defined interface
for the tty driver table.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-13 09:51:42 -07:00
Alan Cox
7d7b93c145 tty: kref the tty driver object
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-13 09:51:42 -07:00
Alan Cox
99f1fe189d tty: Clean up the tty_init_dev changes further
Fix up the naming, style and extract some bits of code into the driver
specific code

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-13 09:51:42 -07:00
Sukadev Bhattiprolu
2349970575 tty: Move parts of tty_init_dev into new functions
Move the 'find-tty' and 'fast-track-open' parts of init_dev() to
separate functions.

Signed-off-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-13 09:51:42 -07:00
Alan Cox
d81ed10307 tty: Remove more special casing and out of place code
Carry on pushing code out of tty_io when it belongs to other drivers. I'm
not 100% happy with some of this and it will be worth revisiting some of the
exports later when the restructuring work is done.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-13 09:51:42 -07:00
Alan Cox
feebed6515 tty: shutdown method
Right now there are various drivers that try to use tty->count to know when
they get the final close. Aristeau Rozanski showed while debugging the vt
sysfs race that this isn't entirely safe.

Instead of driver side tricks to work around this introduce a shutdown which
is called when the tty is being destructed. This also means that the shutdown
method is tied into the refcounting.

Use this to rework the console close/sysfs logic.

Remove lots of special case code from the tty core code. The pty code can now
have a shutdown() method that replaces the special case hackery in the tree
free up paths.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-13 09:51:42 -07:00
Alan Cox
15582d36a1 pty: If the administrator creates a device for a ptmx slave we should not error
The open path for ptmx slaves is via the ptmx device. Opening them any
other way is not allowed. Vegard Nossum found that previously this was not
the case and mknod foo c 128 42; cat foo would produce nasty diagnostics

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-13 09:51:42 -07:00
Alan Cox
934e6ebf96 tty: Redo current tty locking
Currently it is sometimes locked by the tty mutex and sometimes by the
sighand lock. The latter is in fact correct and now we can hand back referenced
objects we can fix this up without problems around sleeping functions.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-13 09:51:41 -07:00
Alan Cox
2cb5998b5f tty: the vhangup syscall is racy
We now have the infrastructure to sort this out but rather than teaching
the syscall tty lock rules we move the hard work into a tty helper

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-13 09:51:41 -07:00
Alan Cox
95f9bfc6b7 tty: Move tty_write_message out of kernel/printk
This is pure tty code so put it in the tty layer where it can be with the
locking relevant material it uses

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-13 09:51:41 -07:00
Alan Cox
452a00d2ee tty: Make get_current_tty use a kref
We now return a kref covered tty reference. That ensures the tty structure
doesn't go away when you have a return from get_current_tty. This is not
enough to protect you from most of the resources being freed behind your
back - yet.

[Updated to include fixes for SELinux problems found by Andrew Morton and
 an s390 leak found while debugging the former]

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-13 09:51:41 -07:00
Alan Cox
f4d2a6c209 tty: compare the tty winsize
We always use the real tty one for stuff so the pty one should not be
compared. As we propagate window changes to both it doesn't currently
matter but will when we tidy up the pty termios logic a bit more

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-13 09:51:41 -07:00
Alan Cox
8f52002183 tty: Termios locking - sort out real_tty confusions and lock reads
This moves us towards sanity and should mean our termios locking is now
complete and comprehensive.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-13 09:51:41 -07:00
Alan Cox
6f967f7891 tty: use krefs to protect driver module counts
The tty layer keeps driver module counts that are used so the driver knows
when it can be unloaded. For obvious reasons we want to tie that to the
refcounting properly.

At this point the driver side itself isn't refcounted nicely but we can do
that later and kref the drivers.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-13 09:51:40 -07:00
Alan Cox
9c9f4ded90 tty: Add a kref count
Introduce a kref to the tty structure and use it to protect the tty->signal
tty references. For now we don't introduce it for anything else.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-13 09:51:40 -07:00
Alan Cox
9e48565d21 tty: Split tty_port into its own file
Not much in it yet but this will grow a lot

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-13 09:51:40 -07:00
Alan Cox
e04957365b tty: split the buffering from tty_io
The two are basically independent chunks of code so lets split them up for
readability and sanity. It also makes the API boundaries much clearer.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-13 09:51:40 -07:00
Alan Cox
e688510773 tty: move tioclinux from a special case
Right now we have ifdefs and hooks in the core ioctl handler for TIOCLINUX
and then test if its a console. This is brain dead. Instead call the
tioclinux helper from the relevant driver ioctl methods.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-13 09:51:40 -07:00
Jason Wessel
0dca0fd2bf kgdboc,tty: Fix tty polling search to use name correctly
The tty_find_polling_driver() routine did not correctly check the base
part of the tty name.  This can lead to kgdboc selecting an incorrect
driver, as well as accepting a completely invalid tty such as "echo
ffff0 > /sys/module/kgdboc/parameters/kgdboc".

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2008-09-26 10:36:42 -05:00
Alan Cox
a152db71d9 tty: Fix termios tty window resize race with pty/tty pair
Kanru Chen posted a patch versus the old code which deals with the case
where you resize the pty side of a pty/tty pair. In that situation the
termios data is updated for both pty and tty but the locks are not held
for the right side.

This implements the fix differently against the updated tty code. Patch
by self but the hard bit (noticing and fixing the bug) is thanks to Kanru
Chen.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-08-27 14:37:09 -07:00
Alan Cox
8c9a9dd0fa tty: remove resize window special case
This moves it to being a tty operation. That removes special cases and now
also means that resize can be picked up by um and other non vt consoles
which may have a resize operation.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-08-15 10:34:07 -07:00
Christian Borntraeger
000b9151d7 Fix race/oops in tty layer after BKL pushdown
While testing our KVM code for s390 (starting and killall kvm in a loop)
I can reproduce the following oops:

  Unable to handle kernel pointer dereference at virtual kernel address 6b6b6b6b6b6b6000 Oops: 0038 [#1] SMP
  Modules linked in: dm_multipath sunrpc qeth_l3 qeth_l2 dm_mod qeth
  ccwgroup CPU: 1 Not tainted 2.6.27-rc1 #54
  Process kuli (pid: 4409, task: 00000000b6aa5940, ksp: 00000000b7343e10)
  Krnl PSW : 0704e00180000000 00000000002e0b8c
  (disassociate_ctty+0x1c0/0x288) R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3
  CC:2 PM:0 EA:3 Krnl GPRS: 0000000000000000 6b6b6b6b6b6b6b6b
  0000000000000001 00000000000003a6 00000000002e0a46 00000000004b4160
  0000000000000001 00000000bbd79758 00000000b7343e58 00000000b8854148
  00000000bd34dea0 00000000b7343c20 0000000000000001 00000000004b6d08
  00000000002e0a46 00000000b7343c20 Krnl Code: 00000000002e0b7e:
  eb9fb0a00004	lmg	%r9,%r15,160(%r11) 00000000002e0b84:
  07f4		bcr	15,%r4 00000000002e0b86:
  e31090080004	lg	%r1,8(%r9) >00000000002e0b8c:
  d501109cd000	clc	156(2,%r1),0(%r13) 00000000002e0b92:
  a784ff5d		brc	8,2e0a4c 00000000002e0b96:
  b9040029		lgr	%r2,%r9 00000000002e0b9a:
  c0e5fffff9c3	brasl	%r14,2dff20 00000000002e0ba0:
  a7f4ff56		brc	15,2e0a4c Call Trace:
  ([<00000000002e0a46>] disassociate_ctty+0x7a/0x288)
   [<0000000000141fe6>] do_exit+0x212/0x8d4
   [<0000000000142708>] do_group_exit+0x60/0xcc
   [<0000000000150660>] get_signal_to_deliver+0x270/0x3ac
   [<000000000010bfd6>] do_signal+0x8e/0x8dc
   [<0000000000113772>] sysc_sigpending+0xe/0x22
   [<000001ff0000b134>] 0x1ff0000b134
  INFO: lockdep is turned off.
  Last Breaking-Event-Address:
   [<00000000002e0a48>] disassociate_ctty+0x7c/0x288
  Kernel panic - not syncing: Fatal exception: panic_on_oops

It seems that tty was already free in disassocate_ctty when it tries
to dereference tty->driver.

After moving the lock_kernel before the mutex_unlock, I can no longer
reproduce the problem.

[ This is a temporary partial fix for the documented and long standing
  race in disassociate_tty.  This stops most problem cases for now.

  For the next release the -next tree has an initial implementation of
  kref counting for tty structures and this quickfix will be dropped.

                                                              - Alan ]

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by; Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-08-11 10:37:34 -07:00
Adrian Bunk
cd9a6f1078 unexport proc_clear_tty
With the removal of the Solaris binary emulation the export of
proc_clear_tty became unused.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25 10:53:44 -07:00
Adrian Bunk
d7ce20b202 remove is_tty()
This patch removes the no longer used is_tty().

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-24 10:47:13 -07:00
Alan Cox
1bad879a07 tty: Fix up escaped character
Louis Rilling noticed this.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-22 20:57:26 -07:00
Linus Torvalds
53baaaa968 Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6: (79 commits)
  arm: bus_id -> dev_name() and dev_set_name() conversions
  sparc64: fix up bus_id changes in sparc core code
  3c59x: handle pci_name() being const
  MTD: handle pci_name() being const
  HP iLO driver
  sysdev: Convert the x86 mce tolerant sysdev attribute to generic attribute
  sysdev: Add utility functions for simple int/ulong variable sysdev attributes
  sysdev: Pass the attribute to the low level sysdev show/store function
  driver core: Suppress sysfs warnings for device_rename().
  kobject: Transmit return value of call_usermodehelper() to caller
  sysfs-rules.txt: reword API stability statement
  debugfs: Implement debugfs_remove_recursive()
  HOWTO: change email addresses of James in HOWTO
  always enable FW_LOADER unless EMBEDDED=y
  uio-howto.tmpl: use unique output names
  uio-howto.tmpl: use standard copyright/legal markings
  sysfs: don't call notify_change
  sysdev: fix debugging statements in registration code.
  kobject: should use kobject_put() in kset-example
  kobject: reorder kobject to save space on 64 bit builds
  ...
2008-07-22 13:13:47 -07:00
Alan Cox
9e98966c7b tty: rework break handling
Some hardware needs to do break handling itself and may have partial
support only. Make break_ctl return an error code. Add a tty driver flag
so you can indicate driver hardware side break support.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-22 13:03:28 -07:00