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  1. 03 4月, 2010 1 次提交
  3. 09 2月, 2010 1 次提交
  5. 08 2月, 2010 1 次提交
    • L
      Fix race in tty_fasync() properly · 80e1e823
      由 Linus Torvalds 提交于 
      This reverts commit 70362511 ("tty: fix race in tty_fasync") and
commit b04da8bf ("fnctl: f_modown should call write_lock_irqsave/
restore") that tried to fix up some of the fallout but was incomplete.

It turns out that we really cannot hold 'tty->ctrl_lock' over calling
__f_setown, because not only did that cause problems with interrupt
disables (which the second commit fixed), it also causes a potential
ABBA deadlock due to lock ordering.

Thanks to Tetsuo Handa for following up on the issue, and running
lockdep to show the problem.  It goes roughly like this:

 - f_getown gets filp->f_owner.lock for reading without interrupts
   disabled, so an interrupt that happens while that lock is held can
   cause a lockdep chain from f_owner.lock -> sighand->siglock.

 - at the same time, the tty->ctrl_lock -> f_owner.lock chain that
   commit 70362511 introduced, together with the pre-existing
   sighand->siglock -> tty->ctrl_lock chain means that we have a lock
   dependency the other way too.

So instead of extending tty->ctrl_lock over the whole __f_setown() call,
we now just take a reference to the 'pid' structure while holding the
lock, and then release it after having done the __f_setown.  That still
guarantees that 'struct pid' won't go away from under us, which is all
we really ever needed.
Reported-and-tested-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: NGreg Kroah-Hartman <gregkh@suse.de>
Acked-by: NAmérico Wang <xiyou.wangcong@gmail.com>
Cc: stable@kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      80e1e823
  7. 21 1月, 2010 1 次提交
    • G
      tty: fix race in tty_fasync · 70362511
      由 Greg Kroah-Hartman 提交于 
      We need to keep the lock held over the call to __f_setown() to
prevent a PID race.

Thanks to Al Viro for pointing out the problem, and to Travis for
making us look here in the first place.

Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Tavis Ormandy <taviso@google.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Julien Tinnes <jln@google.com>
Cc: Matt Mackall <mpm@selenic.com>
Cc: stable <stable@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
      70362511
  9. 13 12月, 2009 1 次提交
  11. 12 12月, 2009 5 次提交
  13. 28 9月, 2009 1 次提交
    • D
      tty: Fix regressions caused by commit b50989dc · f278a2f7
      由 Dave Young 提交于 
      The following commit made console open fails while booting:

	commit b50989dc
	Author: Alan Cox <alan@linux.intel.com>
	Date:   Sat Sep 19 13:13:22 2009 -0700

	tty: make the kref destructor occur asynchronously

Due to tty release routines run in a workqueue now, error like the
following will be reported while booting:

INIT open /dev/console Input/output error

It also causes hibernation regression to appear as reported at
http://bugzilla.kernel.org/show_bug.cgi?id=14229

The reason is that now there's latency issue with closing, but when
we open a "closing not finished" tty, -EIO will be returned.

Fix it as per the following Alan's suggestion:

  Fun but it's actually not a bug and the fix is wrong in itself as
  the port may be closing but not yet being destructed, in which case
  it seems to do the wrong thing.  Opening a tty that is closing (and
  could be closing for long periods) is supposed to return -EIO.

  I suspect a better way to deal with this and keep the old console
  timing is to split tty->shutdown into two functions.

  tty->shutdown() - called synchronously just before we dump the tty
  onto the waitqueue for destruction

  tty->cleanup() - called when the destructor runs.

  We would then do the shutdown part which can occur in IRQ context
  fine, before queueing the rest of the release (from tty->magic = 0
  ...  the end) to occur asynchronously

  The USB update in -next would then need a call like

       if (tty->cleanup)
               tty->cleanup(tty);

  at the top of the async function and the USB shutdown to be split
  between shutdown and cleanup as the USB resource cleanup and final
  tidy cannot occur synchronously as it needs to sleep.

  In other words the logic becomes

       final kref put
               make object unfindable

       async
               clean it up
Signed-off-by: NDave Young <hidave.darkstar@gmail.com>
[ rjw: Rebased on top of 2.6.31-git, reworked the changelog. ]
Signed-off-by: N"Rafael J. Wysocki" <rjw@sisk.pl>
[ Changed serial naming to match new rules, dropped tty_shutdown as per
  comments from Alan Stern  - Linus ]
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      f278a2f7
  15. 20 9月, 2009 4 次提交
  17. 17 6月, 2009 1 次提交
    • A
      tty: fix sanity check · 1aa4bed8
      由 Alan Cox 提交于 
      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: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      1aa4bed8
  19. 11 6月, 2009 4 次提交
  21. 03 4月, 2009 2 次提交
  23. 01 4月, 2009 1 次提交
  25. 16 3月, 2009 1 次提交
    • J
      Use f_lock to protect f_flags · db1dd4d3
      由 Jonathan Corbet 提交于 
      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: NChristoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>
      db1dd4d3
  27. 27 1月, 2009 1 次提交
  29. 03 1月, 2009 3 次提交
    • A
      pty: simplify resize · fc6f6238
      由 Alan Cox 提交于 
      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: NAlan Cox <alan@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      fc6f6238
    • J
      tty: Fix sparse static warning for tty_driver_lookup_tty · a47d545f
      由 Jason Wessel 提交于 
      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: NJason Wessel <jason.wessel@windriver.com>
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      a47d545f
    • J
      n_tty: Fix loss of echoed characters and remove bkl from n_tty · a88a69c9
      由 Joe Peterson 提交于 
      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: NJoe Peterson <joe@skyrush.com>
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      a88a69c9
  31. 09 12月, 2008 1 次提交
    • A
      Audit: Log TIOCSTI · 1e641743
      由 Al Viro 提交于 
      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: NMiloslav Trmac <mitr@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NJames Morris <jmorris@namei.org>
      1e641743
  33. 02 12月, 2008 1 次提交
  35. 17 10月, 2008 1 次提交
  37. 16 10月, 2008 1 次提交
  39. 14 10月, 2008 8 次提交