tty_write_message() allows the caller to directly write to a specific
tty. Since the line discipline is bypassed for the direct write,
nothing prevents the tty from being torn down after the tty count is
checked.
Hold the tty lock for the duration of the direct write.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tiocspgrp() is the ioctl handler for TIOCSPGRP, which runs in
non-atomic context; use spin_lock/unlock_irq (since interrupt state
is on).
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The job_control() check in n_tty_read() has nearly identical purpose
and results as tty_check_change(). Both functions' purpose is to
determine if the current task's pgrp is the foreground pgrp for the tty,
and if not, to signal the current pgrp.
Introduce __tty_check_change() which takes the signal to send
and performs the shared operations for job control() and
tty_check_change().
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This is mostly a hardening fix, given that write-only access to other
users' ttys is usually only given through setgid tty executables.
Signed-off-by: Jann Horn <jann@thejh.net>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit a3a10ce342 ("Avoid usb reset crashes by making tty_io cdevs truly
dynamic") which mixes using cdev_alloc() and cdev_init() is problematic.
Subsequent call to cdev_init() after cdev_alloc() sets kobj release method
from cdev_dynamic_release() to cdev_default_release() and thus makes it
impossible to free allocated cdev.
This patch also consolidates error path of cdev_add() as cdev can also leak
here if things went wrong.
Signed-off-by: Leon Yu <chianglungyu@gmail.com>
Fixes: a3a10ce342 ("Avoid usb reset crashes by making tty_io cdevs truly dynamic")
Acked-by: Richard Watts <rrw@kynesim.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Introduce tty_debug() macro to output uniform debug information for
tty core debug messages (function name and tty name).
Note: printk(KERN_DEBUG) is retained here over pr_debug() since
messages can be enabled in non-DEBUG builds.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Output the function name, tty name, and invariant failure (if applicable).
Add the tty count to the tty_open() message. Fix the disassociate_ctty()
message, which printed the NULL pointer and the wrong message.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
task_pgrp requires an rcu or tasklist lock to be obtained if the returned pid
is to be dereferenced, which kill_pgrp does. Obtain an RCU lock for the
duration of use.
Signed-off-by: Patrick Donnelly <batrick@batbytes.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty_name no longer uses the buf parameter, so remove it along with all
the 64 byte stack buffers that used to be passed in.
Mostly generated by the coccinelle script
@depends on patch@
identifier buf;
constant C;
expression tty;
@@
- char buf[C];
<+...
- tty_name(tty, buf)
+ tty_name(tty)
...+>
allmodconfig compiles, so I'm fairly confident the stack buffers
weren't used for other purposes as well.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
All users of tty_name pass the return value (the provided buffer) to
some printf-like function. We can thus avoid the strcpy and, more
importantly, later remove the buf parameter completely, eliminating
the need for some 64 byte stack buffers.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
All users of tty_name pass the result directly to a printf-like
function. This means we can actually let tty_name return the literal
"NULL tty" or tty->name directly, avoiding the strcpy and a lot of
medium-sized stack buffers. In preparation for that, make the return
type const char*.
While at it, we can also constify the tty parameter.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We only care if anything other than the lower 3 bits of the tty has
changed, so just check that way, which makes it a bit faster, and more
obvious what is going on. Also, document this for future developers to
understand why we did this.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
Instead of manual calls of device_create_file() and
device_remove_file(), pass the static attribute groups using
device_create_with_groups().
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This problem was taken care of three times already in
* b0de59b573 (TTY: do not update
atime/mtime on read/write),
* 37b7f3c765 (TTY: fix atime/mtime
regression), and
* b0b885657b (tty: fix up atime/mtime
mess, take three)
But it still misses one point. As John Paul correctly points out, we
do not care about setting date. If somebody ever changes wall
time backwards (by mistake for example), tty timestamps are never
updated until the original wall time passes.
So check the absolute difference of times and if it large than "8
seconds or so", always update the time. That means we will update
immediatelly when changing time. Ergo, CAP_SYS_TIME can foul the
check, but it was always that way.
Thanks John for serving me this so nicely debugged.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Reported-by: John Paul Perry <john_paul.perry@alcatel-lucent.com>
Cc: <stable@vger.kernel.org> # all, as b0b885657 was backported
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Exclusive mode ttys (TTY_EXCLUSIVE) do not allow further reopens;
fail the condition before associating the file pointer and calling
the driver open() method.
Prevents DTR programming when the tty is already in exclusive mode.
Reported-by: Shreyas Bethur <shreyas.bethur@ni.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Shreyas Bethur <shreyas.bethur@ni.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The functions put_device() and tty_kref_put() test whether their argument
is NULL and then return immediately.
Thus the test around the call is not needed.
This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When somebody calls TIOCSSERIAL ioctl with serial flags to set one of
* ASYNC_SESSION_LOCKOUT
* ASYNC_PGRP_LOCKOUT
* ASYNC_CALLOUT_NOHUP
* ASYNC_AUTOPROBE
nothing happens. We actually ignore the flags for over a decade at
least (I checked 2.6.0).
So start yelling at users who use those flags, that they shouldn't.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Alan Cox <gnomes@lxorguk.ukuu.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The use of older function ptr calling style, (*fn)(), makes static
analysis more error-prone; replace with modern fn() style.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty_hung_up_p() is equivalent to the open-coded test in tty_open().
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We need the fixes in drivers/tty/tty_io.c that were done in there for
future patches in this branch.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty_ldisc_flush() first clears the line discipline input buffer,
then clears the tty flip buffers. However, this allows for existing
data in the tty flip buffers to be added after the ldisc input
buffer has been cleared, but before the flip buffers have been cleared.
Add an optional ldisc parameter to tty_buffer_flush() to allow
tty_ldisc_flush() to pass the ldisc to clear.
NB: Initially, the plan was to do this automatically in
tty_buffer_flush(). However, an audit of the behavior of existing
line disciplines showed that performing a ldisc buffer flush on
ioctl(TCFLSH) was not always the outcome. For example, some line
disciplines have flush_buffer() methods but not ioctl() methods,
so a ->flush_buffer() command would be unexpected.
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When releasing the master pty, the slave pty also needs to be locked
to prevent concurrent tty count changes for the slave pty and to
ensure that only one parallel master and slave release observe the
final close, and proceed to destruct the pty pair. Conversely, when
releasing the slave pty, locking the master pty is not necessary
(since the master's state can be inferred by the slave tty count).
Introduce tty_lock_slave()/tty_unlock_slave() which acquires/releases
the tty lock of the slave pty. Remove tty_lock_pair()/tty_unlock_pair().
Dropping the tty_lock is no longer required to re-establish a stable
lock order.
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The local o_tty variable in tty_release() is now accessed only
when closing the pty master.
Set o_tty to slave pty when closing pty master, otherwise NULL;
use o_tty != NULL as replacement for pty_master.
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Passing the 'other' tty to tty_release_checks() only makes sense
for a pty pair; make o_tty scope local instead.
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Passing the 'other' tty to tty_ldisc_release() only makes sense
for a pty pair; make o_tty function local instead.
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Perform work flush for both ends of a pty pair within tty_flush_works(),
rather than calling twice.
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When the slave side closes and its tty count is 0, the pty
pair can be destroyed; the master side must have already
closed for the slave side tty count to be 0. Thus, only the
pty master close must check if the slave side has closed by
checking the slave tty count.
Remove the pre-computed closing flags and check the actual count(s).
Regular ttys are unaffected by this change.
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Holding the tty_lock() is necessary to prevent concurrent changes
to the tty count that may cause it to differ from the open file
list count. The tty_lock() is already held at all call sites.
NB: Note that the check for the pty master tty count is safe because
the slave's tty_lock() is held while decrementing the pty master
tty count.
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Releasing the tty locks while waiting for the tty wait queues to
be empty is no longer necessary nor desirable. Prior to
"tty: Don't take tty_mutex for tty count changes", dropping the
tty locks was necessary to reestablish the correct lock order between
tty_mutex and the tty locks. Dropping the global tty_mutex was necessary;
otherwise new ttys could not have been opened while waiting.
However, without needing the global tty_mutex held, the tty locks for
the releasing tty can now be held through the sleep. The sanity check
is for abnormal conditions caused by kernel bugs, not for recoverable
errors caused by misbehaving userspace; dropping the tty locks only
allows the tty state to get more sideways.
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Holding tty_mutex is no longer required to serialize changes to
the tty_count or to prevent concurrent opens of closing ttys;
tty_lock() is sufficient.
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Now that re-open is not permitted for a legacy BSD pty master,
using TTY_CLOSING to indicate when a tty can be torn-down is
no longer necessary.
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Holding tty_mutex for a tty re-open is no longer necessary since
"tty: Clarify re-open behavior of master ptys". Because the
slave tty count is no longer accessed by tty_reopen(), holding
tty_mutex to prevent concurrent final tty_release() of the slave
pty is not required.
As with "tty: Re-open /dev/tty without tty_mutex", holding a
tty kref until the tty_lock is acquired is sufficient to ensure
the tty has not been freed, which, in turn, is sufficient to
ensure the tty_lock can be safely acquired and the tty count
can be safely retrieved. A non-zero tty count with the tty lock
held guarantees that release_tty() has not run and cannot
run concurrently with tty_reopen().
Change tty_driver_lookup_tty() to acquire the tty kref, which
allows the tty_mutex to be dropped before acquiring the tty lock.
Dropping the tty_mutex before attempting the tty_lock allows
other ttys to be opened and released, without needing this
tty_reopen() to complete.
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Opening /dev/tty (ie., the controlling tty for the current task)
is always a re-open of the underlying tty. Because holding the
tty_lock is sufficient for safely re-opening a tty, and because
having a tty kref is sufficient for safely acquiring the tty_lock [1],
tty_open_current_tty() does not require holding tty_mutex.
Repurpose tty_open_current_tty() to perform the re-open itself and
refactor tty_open().
[1] Analysis of safely re-opening the current tty w/o tty_mutex
get_current_tty() gets a tty kref from the already kref'ed tty value of
current->signal->tty while holding the sighand lock for the current
task. This guarantees that the tty pointer returned from
get_current_tty() points to a tty which remains referenceable
while holding the kref.
Although release_tty() may run concurrently, and thus the driver
reference may be removed, release_one_tty() cannot have run, and
won't while holding the tty kref.
This, in turn, guarantees the tty_lock() can safely be acquired
(since tty->magic and tty->legacy_mutex are still a valid dereferences).
The tty_lock() also gets a tty kref to prevent the tty_unlock() from
dereferencing a released tty. Thus, the kref returned from
get_current_tty() can be released.
Lastly, the first operation of tty_reopen() is to check the tty count.
If non-zero, this ensures release_tty() is not running concurrently,
and the driver references have not been removed.
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Although perhaps not obvious, the TTY_CLOSING bit is set when the
tty count has been decremented to 0 (which occurs while holding
tty_lock). The only other case when tty count is 0 during a re-open
is when a legacy BSD pty master has been opened in parallel but
after the pty slave, which is unsupported and returns an error.
Thus !tty->count contains the complete set of degenerate conditions
under which a tty open fails.
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Re-opening master ptys is not allowed. Once opened and for the remaining
lifetime of the master pty, its tty count is 1. If its tty count has
dropped to 0, then the master pty was closed and TTY_CLOSING was set,
and destruction may begin imminently.
Besides the normal case of a legacy BSD pty master being re-opened
(which always returns -EIO), this code is only reachable in 2 degenerate
cases:
1. The pty master is the controlling terminal (this is possible through
the TIOCSCTTY ioctl). pty masters are not designed to be controlling
terminals and it's an oversight that tiocsctty() ever let that happen.
The attempted open of /dev/tty will always fail. No known program does
this.
2. The legacy BSD pty slave was opened first. The slave open will fail
in pty_open() and tty_release() will commence. But before tty_release()
claims the tty_mutex, there is a very small window where a parallel
master open might succeed. In a test of racing legacy BSD slave and
master parallel opens, where:
slave open attempts: 10000 success:4527 failure:5473
master open attempts: 11728 success:5789 failure:5939
only 8 master open attempts would have succeeded reaching this code and
successfully opened the master pty. This case is not possible with
SysV ptys.
Always return -EIO if a master pty is re-opened or the slave is opened
first and the master opened in parallel (for legacy BSD ptys).
Furthermore, now that changing the slave's count is not required,
the tty_lock is sufficient for preventing concurrent changes to the
tty being re-opened (or failing re-opening).
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Now that tty_ldisc_hangup() does not drop the tty lock, it is no
longer possible to observe TTY_HUPPING while holding the tty lock
on another cpu.
Remove TTY_HUPPING bit definition.
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The session and foreground process group pid references will be
non-NULL if tiocsctty() is stealing the controlling tty from another
session (ie., arg == 1 in tiocsctty()).
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Setting the controlling terminal for a session occurs with either
the first open of a non-pty master tty or with ioctl(TIOCSCTTY).
Since only the session leader can set the controlling terminal for
a session (and the session leader cannot change), it is not
necessary to prevent a process from attempting to set different
ttys as the controlling terminal concurrently.
So it's only necessary to prevent the same tty from becoming the
controlling terminal for different session leaders. The tty_lock()
is sufficient to prevent concurrent proc_set_tty() for the same
tty.
Remove the tty_mutex lock region; add tty_lock() to tiocsctty().
While this may appear to allow a race condition between opening
the controlling tty via tty_open_current_tty() and stealing the
controlling tty via ioctl(TIOCSCTTY, 1), that race condition already
existed. Even if the tty_mutex prevented stealing the controlling tty
while tty_open_current_tty() returned the original controlling tty,
it cannot prevent stealing the controlling tty before tty_open() returns.
Thus, tty_open() could already return a no-longer-controlling tty when
opening /dev/tty.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tiocspgrp() is the lone caller of session_of_pgrp(); relocate and
limit to file scope.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Claim a read lock on the tasklist_lock while setting the controlling
terminal for the session leader. This fixes multiple races:
1. task_pgrp() and task_session() cannot be safely dereferenced, such
as passing to get_pid(), without holding either rcu_read_lock() or
tasklist_lock
2. setsid() unwisely allows any thread in the thread group to
make the thread group leader the session leader; this makes the
unlocked reads of ->signal->leader and signal->tty potentially
unordered, stale or even have spurious values.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The tty parameter to __proc_set_tty() cannot be NULL; all
call sites have already dereferenced tty.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Only the current task itself can set its controlling tty (other
than before the task has been forked). Equivalent to existing usage.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Move the controlling tty-related functions and remove forward
declarations for __proc_set_tty() and proc_set_tty().
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty_pair_get_pty() has no in-tree users and tty_pair_get_tty()
has only one file-local user. Remove the external declarations,
the export declarations, and declare tty_pair_get_tty() static.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sparse lock annotations cannot represent conditional acquire, such
as mutex_lock_interruptible() or mutex_trylock(), and produce sparse
warnings at _every_ correct call site.
Remove lock annotations from tty_write_lock() and tty_write_unlock().
Fixes sparse warnings:
drivers/tty/tty_io.c:1083:13: warning: context imbalance in 'tty_write_unlock' - wrong count at exit
drivers/tty/tty_io.c:1090:12: warning: context imbalance in 'tty_write_lock' - wrong count at exit
drivers/tty/tty_io.c:1211:17: warning: context imbalance in 'tty_write_message' - unexpected unlock
drivers/tty/tty_io.c:1233:16: warning: context imbalance in 'tty_write' - different lock contexts for basic block
drivers/tty/tty_io.c:1285:5: warning: context imbalance in 'tty_send_xchar' - different lock contexts for basic block
drivers/tty/tty_io.c:2653:12: warning: context imbalance in 'send_break' - different lock contexts for basic block
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Only print one warning when a task is on the read_wait or write_wait
wait queue at final tty release.
Cc: <stable@vger.kernel.org> # 3.4.x+
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Kernel oops can cause the tty to be unreleaseable (for example, if
n_tty_read() crashes while on the read_wait queue). This will cause
tty_release() to endlessly loop without sleeping.
Use a killable sleep timeout which grows by 2n+1 jiffies over the interval
[0, 120 secs.) and then jumps to forever (but still killable).
NB: killable just allows for the task to be rewoken manually, not
to be terminated.
Cc: <stable@vger.kernel.org> # since before 2.6.32
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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-----END PGP SIGNATURE-----
Merge tag 'locks-v3.18-1' of git://git.samba.org/jlayton/linux
Pull file locking related changes from Jeff Layton:
"This release is a little more busy for file locking changes than the
last:
- a set of patches from Kinglong Mee to fix the lockowner handling in
knfsd
- a pile of cleanups to the internal file lease API. This should get
us a bit closer to allowing for setlease methods that can block.
There are some dependencies between mine and Bruce's trees this cycle,
and I based my tree on top of the requisite patches in Bruce's tree"
* tag 'locks-v3.18-1' of git://git.samba.org/jlayton/linux: (26 commits)
locks: fix fcntl_setlease/getlease return when !CONFIG_FILE_LOCKING
locks: flock_make_lock should return a struct file_lock (or PTR_ERR)
locks: set fl_owner for leases to filp instead of current->files
locks: give lm_break a return value
locks: __break_lease cleanup in preparation of allowing direct removal of leases
locks: remove i_have_this_lease check from __break_lease
locks: move freeing of leases outside of i_lock
locks: move i_lock acquisition into generic_*_lease handlers
locks: define a lm_setup handler for leases
locks: plumb a "priv" pointer into the setlease routines
nfsd: don't keep a pointer to the lease in nfs4_file
locks: clean up vfs_setlease kerneldoc comments
locks: generic_delete_lease doesn't need a file_lock at all
nfsd: fix potential lease memory leak in nfs4_setlease
locks: close potential race in lease_get_mtime
security: make security_file_set_fowner, f_setown and __f_setown void return
locks: consolidate "nolease" routines
locks: remove lock_may_read and lock_may_write
lockd: rip out deferred lock handling from testlock codepath
NFSD: Get reference of lockowner when coping file_lock
...
Relocate the file-scope function, send_prio_char(), as a global
helper tty_send_xchar(). Remove the global declarations for
tty_write_lock()/tty_write_unlock(), as these are file-scope only now.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When a master pty is set to packet mode, flow control changes to
the slave pty cause notifications to the master pty via reads and
polls. However, these tests are occurring for all ttys, not
just ptys.
Implement flow control packet mode notifications in the pty driver.
Only the slave side implements the flow control handlers since
packet mode is asymmetric; the master pty receives notifications
for slave-side changes, but not vice versa.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Without serialization, the flow control state can become inverted
wrt. the actual hardware state. For example,
CPU 0 | CPU 1
stop_tty() |
lock ctrl_lock |
tty->stopped = 1 |
unlock ctrl_lock |
| start_tty()
| lock ctrl_lock
| tty->stopped = 0
| unlock ctrl_lock
| driver->start()
driver->stop() |
In this case, the flow control state now indicates the tty has
been started, but the actual hardware state has actually been stopped.
Introduce tty->flow_lock spinlock to serialize tty flow control changes.
Split out unlocked __start_tty()/__stop_tty() flavors for use by
ioctl(TCXONC) in follow-on patch.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
security_file_set_fowner always returns 0, so make it f_setown and
__f_setown void return functions and fix up the error handling in the
callers.
Cc: linux-security-module@vger.kernel.org
Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
The two functions alloc_tty_struct and initialize_tty_struct are
always called together. Merge them into alloc_tty_struct, updating its
prototype and the only two callers of these functions.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The 'active' sysfs attribute should refer to the currently active tty
devices the console is running on, not the currently active console. The
console structure doesn't refer to any device in sysfs, only the tty the
console is running on has. So we need to print out the tty names in
'active', not the console names.
There is one special-case, which is tty0. If the console is directed to
it, we want 'tty0' to show up in the file, so user-space knows that the
messages get forwarded to the active VT. The ->device() callback would
resolve tty0, though. Hence, treat it special and don't call into the VT
layer to resolve it (plymouth is known to depend on it).
Cc: Lennart Poettering <lennart@poettering.net>
Cc: Kay Sievers <kay@vrfy.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Werner Fink <werner@suse.de>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit d8a5dc3033.
This breaks plymouth installs, either because plymouth is using the file
"incorrectly" or because the patch is incorrect. Either way, this needs
to be reverted until it is all figured out.
Reported-by: Josh Boyer <jwboyer@fedoraproject.org>
Reported-by: Ray Strode <halfline@gmail.com>
Cc: Lennart Poettering <lennart@poettering.net>
Cc: Kay Sievers <kay@vrfy.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: David Herrmann <dh.herrmann@gmail.com>
Cc: Werner Fink <werner@suse.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The 'active' sysfs attribute should refer to the currently active tty
devices the console is running on, not the currently active console.
The console structure doesn't refer to any device in sysfs, only the tty
the console is running on has. So we need to print out the tty names in
'active', not the console names.
This resolves an issue on s390 platforms in determining the correct
console device to use.
Cc: Lennart Poettering <lennart@poettering.net>
Cc: Kay Sievers <kay@vrfy.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Werner Fink <werner@suse.de>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
A common security idiom is to hangup the current tty (via vhangup())
after forking but before execing a root shell. This hangs up any
existing opens which other processes may have and ensures subsequent
opens have the necessary permissions to open the root shell tty/pty.
Reset the TTY_HUPPED state after the driver has successfully
returned the opened tty (perform the reset while the tty is locked
to avoid racing with concurrent hangups).
Reported-by: Heorhi Valakhanovich <valahanovich@tut.by>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Cc: stable <stable@vger.kernel.org> # 3.12
Tested-by: Heorhi Valakhanovich <valahanovich@tut.by>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Starting from v3.10 (probably commit f91e2590410b: "tty: Signal
foreground group processes in hangup") disassociate_ctty() sends SIGCONT
if tty && on_exit. This breaks LSB test-suite, in particular test8 in
_exit.c and test40 in sigcon5.c.
Put the "!on_exit" check back to restore the old behaviour.
Review by Peter Hurley:
"Yes, this regression was introduced by me in that commit. The effect
of the regression is that ptys will receive a SIGCONT when, in similar
circumstances, ttys would not.
The fact that two test vectors accidentally tripped over this
regression suggests that some other apps may as well.
Thanks for catching this"
Cc: stable@vger.kernel.org # v3.10+
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reported-by: Karel Srot <ksrot@redhat.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Instrumented testing shows a tty can be hungup multiple times [1].
Although concurrent hangups are properly serialized, multiple
hangups for the same tty should be prevented.
If tty has already been HUPPED, abort hangup. Note it is not
necessary to cleanup file *redirect on subsequent hangups,
as only TIOCCONS can set that value and ioctls are disabled
after hangup.
[1]
Test performed by simulating a concurrent async hangup via
tty_hangup() with a sync hangup via tty_vhangup(), while
__tty_hangup() was instrumented with:
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 26bb78c..fe8b061 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -629,6 +629,8 @@ static void __tty_hangup(struct tty_struct *tty, int exit_session)
tty_lock(tty);
+ WARN_ON(test_bit(TTY_HUPPED, &tty->flags));
+
/* some functions below drop BTM, so we need this bit */
set_bit(TTY_HUPPING, &tty->flags);
Test result:
WARNING: at /home/peter/src/kernels/mainline/drivers/tty/tty_io.c:632 __tty_hangup+0x459/0x460()
Modules linked in: ip6table_filter ip6_tables ebtable_nat <...snip...>
CPU: 6 PID: 1197 Comm: kworker/6:2 Not tainted 3.10.0-0+rfcomm-xeon #0+rfcomm
Hardware name: Dell Inc. Precision WorkStation T5400 /0RW203, BIOS A11 04/30/2012
Workqueue: events do_tty_hangup
0000000000000009 ffff8802b16d7d18 ffffffff816b553e ffff8802b16d7d58
ffffffff810407e0 ffff880254f95c00 ffff880254f95c00 ffff8802bfd92b00
ffff8802bfd96b00 ffff880254f95e40 0000000000000180 ffff8802b16d7d68
Call Trace:
[<ffffffff816b553e>] dump_stack+0x19/0x1b
[<ffffffff810407e0>] warn_slowpath_common+0x70/0xa0
[<ffffffff8104082a>] warn_slowpath_null+0x1a/0x20
[<ffffffff813fb279>] __tty_hangup+0x459/0x460
[<ffffffff8107409c>] ? finish_task_switch+0xbc/0xe0
[<ffffffff813fb297>] do_tty_hangup+0x17/0x20
[<ffffffff8105fd6f>] process_one_work+0x16f/0x450
[<ffffffff8106007c>] process_scheduled_works+0x2c/0x40
[<ffffffff8106060a>] worker_thread+0x26a/0x380
[<ffffffff810603a0>] ? rescuer_thread+0x310/0x310
[<ffffffff810698a0>] kthread+0xc0/0xd0
[<ffffffff816b0000>] ? destroy_compound_page+0x65/0x92
[<ffffffff810697e0>] ? kthread_create_on_node+0x130/0x130
[<ffffffff816c495c>] ret_from_fork+0x7c/0xb0
[<ffffffff810697e0>] ? kthread_create_on_node+0x130/0x130
---[ end trace 98d9f01536cf411e ]---
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In canonical mode, an EOF which is not the first character of the line
causes read() to complete and return the number of characters read so
far (commonly referred to as EOF push). However, if the previous read()
returned because the user buffer was full _and_ the next character
is an EOF not at the beginning of the line, read() must not return 0,
thus mistakenly indicating the end-of-file condition.
The TTY_PUSH flag is used to indicate an EOF was received which is not
at the beginning of the line. Because the EOF push condition is
evaluated by a thread other than the read(), multiple EOF pushes can
cause a premature end-of-file to be indicated.
Instead, discover the 'EOF push as first read character' condition
from the read() thread itself, and restart the i/o loop if detected.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
No tty driver modifies termios during throttle() or unthrottle().
Therefore, only read safety is required.
However, tty_throttle_safe and tty_unthrottle_safe must still be
mutually exclusive; introduce throttle_mutex for that purpose.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Line discipline locking was performed with a combination of
a mutex, a status bit, a count, and a waitqueue -- basically,
a rw semaphore.
Replace the existing combination with an ld_semaphore.
Fixes:
1) the 'reference acquire after ldisc locked' bug
2) the over-complicated halt mechanism
3) lock order wrt. tty_lock()
4) dropping locks while changing ldisc
5) previously unidentified deadlock while locking ldisc from
both linked ttys concurrently
6) previously unidentified recursive deadlocks
Adds much-needed lockdep diagnostics.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The file scope spinlock identifier, tty_ldisc_lock, will collide
with the file scope lock function tty_ldisc_lock() so rename it.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 19ffd68f81
('pty: Remove redundant itty reset') introduced a regression
whereby the other pty's linkage is not cleared on teardown.
This triggers a false positive diagnostic in testing.
Properly reset the itty linkage.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Cc: stable <stable@vger.kernel.org> # 3.10
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
minimum_to_wake is unique to N_TTY processing, and belongs in
per-ldisc data.
Add the ldisc method, ldisc_ops::fasync(), to notify line disciplines
when signal-driven I/O is enabled or disabled. When enabled for N_TTY
(by fcntl(F_SETFL, O_ASYNC)), blocking reader/polls will be woken
for any readable input. When disabled, blocking reader/polls are not
woken until the read buffer is full.
Canonical mode (L_ICANON(tty), n_tty_data::icanon) is not affected by
the minimum_to_wake setting.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We first tried to avoid updating atime/mtime entirely (commit
b0de59b5733d: "TTY: do not update atime/mtime on read/write"), and then
limited it to only update it occasionally (commit 37b7f3c76595: "TTY:
fix atime/mtime regression"), but it turns out that this was both
insufficient and overkill.
It was insufficient because we let people attach to the shared ptmx node
to see activity without even reading atime/mtime, and it was overkill
because the "only once a minute" means that you can't really tell an
idle person from an active one with 'w'.
So this tries to fix the problem properly. It marks the shared ptmx
node as un-notifiable, and it lowers the "only once a minute" to a few
seconds instead - still long enough that you can't time individual
keystrokes, but short enough that you can tell whether somebody is
active or not.
Reported-by: Simon Kirby <sim@hostway.ca>
Acked-by: Jiri Slaby <jslaby@suse.cz>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Here's the big tty/serial driver merge request for 3.10-rc1
Once again, Jiri has a number of TTY driver fixes and cleanups, and
Peter Hurley came through with a bunch of ldisc fixes that resolve a
number of reported issues. There are some other serial driver cleanups
as well.
All of these have been in the linux-next tree for a while.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'tty-3.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
Pull tty/serial driver update from Greg Kroah-Hartman:
"Here's the big tty/serial driver merge request for 3.10-rc1
Once again, Jiri has a number of TTY driver fixes and cleanups, and
Peter Hurley came through with a bunch of ldisc fixes that resolve a
number of reported issues. There are some other serial driver
cleanups as well.
All of these have been in the linux-next tree for a while"
* tag 'tty-3.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (117 commits)
tty/serial/sirf: fix MODULE_DEVICE_TABLE
serial: mxs: drop superfluous {get|put}_device
serial: mxs: fix buffer overflow
ARM: PL011: add support for extended FIFO-size of PL011-r1p5
serial_core.c: add put_device() after device_find_child()
tty: Fix unsafe bit ops in tty_throttle_safe/unthrottle_safe
serial: sccnxp: Replace pdata.init/exit with regulator API
serial: sccnxp: Do not override device name
TTY: pty, fix compilation warning
TTY: rocket, fix compilation warning
TTY: ircomm: fix DTR being raised on hang up
TTY: synclinkmp: fix DTR being raised on hang up
TTY: synclink_gt: fix DTR being raised on hang up
TTY: synclink: fix DTR being raised on hang up
serial: 8250_dw: Fix the stub for dw8250_probe_acpi()
serial: 8250_dw: Convert to devm_ioremap()
serial: 8250_dw: Set port capabilities based on CPR register
serial: 8250_dw: Let ACPI code extract the DMA client info
serial: 8250_dw: Support clk framework also with ACPI
serial: 8250_dw: Enable runtime PM
...
In commit b0de59b573 ("TTY: do not update atime/mtime on read/write")
we removed timestamps from tty inodes to fix a security issue and waited
if something breaks. Well, 'w', the utility to find out logged users
and their inactivity time broke. It shows that users are inactive since
the time they logged in.
To revert to the old behaviour while still preventing attackers to
guess the password length, we update the timestamps in one-minute
intervals by this patch.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
test_bit() is already atomic; drop mutex lock/unlock.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The tty core relies on the ldisc layer for synchronizing destruction
of the tty. Instead, the final tty release must wait for any pending tty
work to complete prior to tty destruction.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Waiting for buffer work to complete is not required for safely
performing changes to the line discipline, once the line discipline
is halted. The buffer work routine, flush_to_ldisc(), will be
unable to acquire an ldisc ref and all existing references were
waited until released (so it can't already have one).
Ensure running buffer work which may reference the soon-to-be-gone
tty completes and any buffer work running after this point retrieves
a NULL tty.
Also, ensure all buffer work is cancelled on port destruction.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty_ldisc_hangup() guarantees the ldisc is enabled (or that there
is no ldisc). Since __tty_hangup() was the only user, re-define
tty_ldisc_enable() in file-scope.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
An exiting session leader can hang if a foreground process is
blocking for line discipline i/o, eg. in n_tty_read(). This happens
because the blocking reader is holding an ldisc reference (indicating
the line discipline is in-use) which prevents __tty_hangup() from
recycling the line discipline. Although waiters are woken before
attempting to gain exclusive access for changing the ldisc, the
blocking reader in this case will not exit the i/o loop since it
has not yet received SIGHUP (because it has not been sent).
Instead, perform signalling first, then recycle the line discipline.
Fixes:
INFO: task init:1 blocked for more than 120 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
init D 00000000001d7180 2688 1 0 0x00000002
ffff8800b9acfba8 0000000000000002 00000000001d7180 ffff8800b9b10048
ffff8800b94cb000 ffff8800b9b10000 00000000001d7180 00000000001d7180
ffff8800b9b10000 ffff8800b9acffd8 00000000001d7180 00000000001d7180
Call Trace:
[<ffffffff83db9909>] __schedule+0x2e9/0x3b0
[<ffffffff83db9b35>] schedule+0x55/0x60
[<ffffffff83db74ba>] schedule_timeout+0x3a/0x370
[<ffffffff81182349>] ? mark_held_locks+0xf9/0x130
[<ffffffff83dbab38>] ? down_failed+0x108/0x200
[<ffffffff83dbb7ab>] ? _raw_spin_unlock_irq+0x2b/0x80
[<ffffffff81182608>] ? trace_hardirqs_on_caller+0x128/0x160
[<ffffffff83dbab61>] down_failed+0x131/0x200
[<ffffffff83dbbfad>] ? tty_ldisc_lock_pair_timeout+0xcd/0x120
[<ffffffff83dbae03>] ldsem_down_write+0xd3/0x113
[<ffffffff83dbbfad>] ? tty_ldisc_lock_pair_timeout+0xcd/0x120
[<ffffffff8118264d>] ? trace_hardirqs_on+0xd/0x10
[<ffffffff83dbbfad>] tty_ldisc_lock_pair_timeout+0xcd/0x120
[<ffffffff81c3df60>] tty_ldisc_hangup+0xd0/0x220
[<ffffffff81c35bd7>] __tty_hangup+0x137/0x4f0
[<ffffffff81c37c7c>] disassociate_ctty+0x6c/0x230
[<ffffffff8111290c>] do_exit+0x41c/0x590
[<ffffffff8107ad34>] ? syscall_trace_enter+0x24/0x2e0
[<ffffffff81112b4a>] do_group_exit+0x8a/0xc0
[<ffffffff81112b92>] sys_exit_group+0x12/0x20
[<ffffffff83dc49d8>] tracesys+0xe1/0xe6
1 lock held by init/1:
#0: (&tty->ldisc_sem){++++++}, at: [<ffffffff83dbbfad>] tty_ldisc_lock_pair_timeout+0xcd/0x120
Reported-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When the session leader is exiting, signal the foreground group
processes as part of the hangup sequence, instead of after the
hangup is complete. This prepares for hanging up the
line discipline _after_ signalling processes which
may be blocking on ldisc i/o.
Parameterize __tty_hangup() to distinguish between when the
session leader is exiting and all other hangups; signal the
foreground group after signalling the session leader and its
process group, which preserves the original signal order.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The interrupt state does not need to be saved, disabled and
restored here; interrupts are already off because this lock
is bracketed by spin_lock_irq/spin_unlock_irq.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
__tty_hangup() and tty_vhangup() cannot be called from atomic context,
so locks do not need to preserve the interrupt state (although,
still disable interrupts).
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull s390 update from Martin Schwidefsky:
"The most prominent change in this patch set is the software dirty bit
patch for s390. It removes __HAVE_ARCH_PAGE_TEST_AND_CLEAR_DIRTY and
the page_test_and_clear_dirty primitive which makes the common memory
management code a bit less obscure.
Heiko fixed most of the PCI related fallout, more often than not
missing GENERIC_HARDIRQS dependencies. Notable is one of the 3270
patches which adds an export to tty_io to be able to resize a tty.
The rest is the usual bunch of cleanups and bug fixes."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (42 commits)
s390/module: Add missing R_390_NONE relocation type
drivers/gpio: add missing GENERIC_HARDIRQ dependency
drivers/input: add couple of missing GENERIC_HARDIRQS dependencies
s390/cleanup: rename SPP to LPP
s390/mm: implement software dirty bits
s390/mm: Fix crst upgrade of mmap with MAP_FIXED
s390/linker skript: discard exit.data at runtime
drivers/media: add missing GENERIC_HARDIRQS dependency
s390/bpf,jit: add vlan tag support
drivers/net,AT91RM9200: add missing GENERIC_HARDIRQS dependency
iucv: fix kernel panic at reboot
s390/Kconfig: sort list of arch selected config options
phylib: remove !S390 dependeny from Kconfig
uio: remove !S390 dependency from Kconfig
dasd: fix sysfs cleanup in dasd_generic_remove
s390/pci: fix hotplug module init
s390/pci: cleanup clp page allocation
s390/pci: cleanup clp inline assembly
s390/perf: cpum_cf: fallback to software sampling events
s390/mm: provide PAGE_SHARED define
...
Here's the big tty/serial driver patches for 3.9-rc1.
More tty port rework and fixes from Jiri here, as well as lots of
individual serial driver updates and fixes.
All of these have been in the linux-next tree for a while.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'tty-3.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
Pull tty/serial patches from Greg Kroah-Hartman:
"Here's the big tty/serial driver patches for 3.9-rc1.
More tty port rework and fixes from Jiri here, as well as lots of
individual serial driver updates and fixes.
All of these have been in the linux-next tree for a while."
* tag 'tty-3.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (140 commits)
tty: mxser: improve error handling in mxser_probe() and mxser_module_init()
serial: imx: fix uninitialized variable warning
serial: tegra: assume CONFIG_OF
TTY: do not update atime/mtime on read/write
lguest: select CONFIG_TTY to build properly.
ARM defconfigs: add missing inclusions of linux/platform_device.h
fb/exynos: include platform_device.h
ARM: sa1100/assabet: include platform_device.h directly
serial: imx: Fix recursive locking bug
pps: Fix build breakage from decoupling pps from tty
tty: Remove ancient hardpps()
pps: Additional cleanups in uart_handle_dcd_change
pps: Move timestamp read into PPS code proper
pps: Don't crash the machine when exiting will do
pps: Fix a use-after free bug when unregistering a source.
pps: Use pps_lookup_dev to reduce ldisc coupling
pps: Add pps_lookup_dev() function
tty: serial: uartlite: Support uartlite on big and little endian systems
tty: serial: uartlite: Fix sparse and checkpatch warnings
serial/arc-uart: Miscll DT related updates (Grant's review comments)
...
Fix up trivial conflicts, mostly just due to the TTY config option
clashing with the EXPERIMENTAL removal.
On http://vladz.devzero.fr/013_ptmx-timing.php, we can see how to find
out length of a password using timestamps of /dev/ptmx. It is
documented in "Timing Analysis of Keystrokes and Timing Attacks on
SSH". To avoid that problem, do not update time when reading
from/writing to a TTY.
I am afraid of regressions as this is a behavior we have since 0.97
and apps may expect the time to be current, e.g. for monitoring
whether there was a change on the TTY. Now, there is no change. So
this would better have a lot of testing before it goes upstream.
References: CVE-2013-0160
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: stable <stable@vger.kernel.org> # after 3.9 is out
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Convert the synchronous size sense code to an interrupt driven
approach. This allows to set the device online even if the
terminal is not connected. With the new code views can be
registered without a connected terminal, the tty can be opened
as soon as the device is online. After the terminal has been
connected and the size has been determined the tty is resized
to match the device characteristics..
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Nothing outside of drivers/tty/tty_io.c references these functions, so
mark them static.
Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
For checkpoint/restore we need to know if tty has
exclusive or packet mode set, as well as if pty
is currently locked. Just to be able to restore
this characteristics.
For this sake the following ioctl codes are introduced
- TIOCGPKT to get packet mode state
- TIOCGPTLCK to get Pty locked state
- TIOCGEXCL to get Exclusive mode state
Note this ioctls are a bit unsafe in terms of data
obtained consistency. The tty characteristics might
be changed right after ioctl complete. Keep it in
mind and use this ioctl carefully.
v2:
- Use TIOC prefix for ioctl codes (by jslaby@)
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
CC: Alan Cox <alan@lxorguk.ukuu.org.uk>
CC: "H. Peter Anvin" <hpa@zytor.com>
CC: Pavel Emelyanov <xemul@parallels.com>
CC: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
So this is it. The big step why we did all the work over the past
kernel releases. Now everything is prepared, so nothing protects us
from doing that big step.
| | \ \ nnnn/^l | |
| | \ / / | |
| '-,.__ => \/ ,-` => | '-,.__
| O __.´´) ( .` | O __.´´)
~~~ ~~ `` ~~~ ~~
The buffers are now in the tty_port structure and we can start
teaching the buffer helpers (insert char/string, flip etc.) to use
tty_port instead of tty_struct all around.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
For that purpose we have to temporarily introduce a second tty back
pointer into tty_port. It is because serial layer, and maybe others,
still do not use tty_port_tty_set/get. So that we cannot set the
tty_port->tty to NULL at will now.
Yes, the fix would be to convert whole serial layer and all its users
to tty_port_tty_set/get. However we are in the process of removing the
need of tty in most of the call sites, so this would lead to a
duplicated work.
Instead we have now tty_port->itty (internal tty) which will be used
only in flush_to_ldisc. For that one it is ensured that itty is valid
wherever the work is run. IOW, the work is synchronously cancelled
before we set itty to NULL and also before hangup is processed.
After we need only tty_port and not tty_struct in most code, this
shall be changed to tty_port_tty_set/get and itty removed completely.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
atomic_write_lock is not n_tty specific, so move it up in the
tty_struct.
And since these are the last ones to move, remove also the comment
saying there are some ldisc' members. There are none now.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Here we start moving all the n_tty related bits from tty_struct to
the newly defined n_tty_data struct in n_tty proper.
In this patch primitive members and bits are moved. The rest will be
done per-partes in the next patches.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Now that we have control over tty->driver_data in pty, we can just
kill the /dev/pts/ in pty code too. Namely, in ->shutdown hook of
tty. For pty, this is called only once, for whichever end is closed
last. But we don't care, both driver_data are the inode as it used to
be till now.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull vfs update from Al Viro:
- big one - consolidation of descriptor-related logics; almost all of
that is moved to fs/file.c
(BTW, I'm seriously tempted to rename the result to fd.c. As it is,
we have a situation when file_table.c is about handling of struct
file and file.c is about handling of descriptor tables; the reasons
are historical - file_table.c used to be about a static array of
struct file we used to have way back).
A lot of stray ends got cleaned up and converted to saner primitives,
disgusting mess in android/binder.c is still disgusting, but at least
doesn't poke so much in descriptor table guts anymore. A bunch of
relatively minor races got fixed in process, plus an ext4 struct file
leak.
- related thing - fget_light() partially unuglified; see fdget() in
there (and yes, it generates the code as good as we used to have).
- also related - bits of Cyrill's procfs stuff that got entangled into
that work; _not_ all of it, just the initial move to fs/proc/fd.c and
switch of fdinfo to seq_file.
- Alex's fs/coredump.c spiltoff - the same story, had been easier to
take that commit than mess with conflicts. The rest is a separate
pile, this was just a mechanical code movement.
- a few misc patches all over the place. Not all for this cycle,
there'll be more (and quite a few currently sit in akpm's tree)."
Fix up trivial conflicts in the android binder driver, and some fairly
simple conflicts due to two different changes to the sock_alloc_file()
interface ("take descriptor handling from sock_alloc_file() to callers"
vs "net: Providing protocol type via system.sockprotoname xattr of
/proc/PID/fd entries" adding a dentry name to the socket)
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (72 commits)
MAX_LFS_FILESIZE should be a loff_t
compat: fs: Generic compat_sys_sendfile implementation
fs: push rcu_barrier() from deactivate_locked_super() to filesystems
btrfs: reada_extent doesn't need kref for refcount
coredump: move core dump functionality into its own file
coredump: prevent double-free on an error path in core dumper
usb/gadget: fix misannotations
fcntl: fix misannotations
ceph: don't abuse d_delete() on failure exits
hypfs: ->d_parent is never NULL or negative
vfs: delete surplus inode NULL check
switch simple cases of fget_light to fdget
new helpers: fdget()/fdput()
switch o2hb_region_dev_write() to fget_light()
proc_map_files_readdir(): don't bother with grabbing files
make get_file() return its argument
vhost_set_vring(): turn pollstart/pollstop into bool
switch prctl_set_mm_exe_file() to fget_light()
switch xfs_find_handle() to fget_light()
switch xfs_swapext() to fget_light()
...
iterates through the opened files in given descriptor table,
calling a supplied function; we stop once non-zero is returned.
Callback gets struct file *, descriptor number and const void *
argument passed to iterator. It is called with files->file_lock
held, so it is not allowed to block.
tty_io, netprio_cgroup and selinux flush_unauthorized_files()
converted to its use.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Added tty_device_create_release() and bound to dev->release in
tty_register_device_attr().
Added tty_port_register_device_attr() and used in uart_add_one_port()
instead of tty_register_device_attr().
Signed-off-by: Tomas Hlavacek <tmshlvck@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Added file /sys/devices/.../tty/ttySX/uartclk to allow reading
uartclk value in struct uart_port in serial_core via sysfs.
tty_register_device() has been generalized and refactored in order
to add support for setting drvdata and attribute_group to the device.
Signed-off-by: Tomas Hlavacek <tmshlvck@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
At commit 07d106d0, Linus pointed out that ENOIOCTLCMD should be
translated as ENOTTY to user mode.
For example:
fd = open("/dev/tty", O_RDWR);
ioctl(fd, -1, &argp);
then the errno should be ENOTTY but not EINVAL.
Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
And if not, complain loudly. None in-kernel module should trigger
that, but let us find out for sure. On the other hand, all the
out-of-tree modules will hit that. Give them some time (maybe one
release) to catch up.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We need the /dev/ node not to be available before we call
tty_register_device. Otherwise we might race with open and
tty_struct->port might not be available at that time.
This is not an issue now, but would be a problem after "TTY: use
tty_port_register_device" is applied.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This allows drivers like ttyprintk to avoid hacks to create an
unnumbered node in /dev. It used to set TTY_DRIVER_DYNAMIC_DEV in
flags and call device_create on its own. That is incorrect, because
TTY_DRIVER_DYNAMIC_DEV may be set only if tty_register_device is
called explicitly.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
So now, that we have flags and know everything needed, keep a promise
and move all the tables and ports allocation from tty_register_driver
to tty_alloc_driver.
Not only that it makes sense, but we need this for
tty_port_link_device which needs tty_driver->ports but is to be called
before tty_register_driver.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We need to allow drivers that use neither tty_port_install nor
tty_port_register_device to link a tty_port to a tty somehow. To
avoid a race with open, this has to be performed before
tty_register_device. But currently tty_driver->ports is allocated even
in tty_register_device because we do not know whether this is the PTY
driver. The PTY driver is special here due to an excessive count of
lines it declares to handle. We cannot handle tty_ports there this
way.
To circumvent this, we start passing tty_driver flags to
alloc_tty_driver already and we create tty_alloc_driver for this
purpose. There we can allocate tty_driver->ports and do all the magic
between tty_alloc_driver and tty_register_device. Later we will
introduce tty_port_link_device function for that purpose.
All drivers should eventually switch to this new tty driver allocation
interface.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The termios and other changes mean the other protections needed on the driver
tty arrays should be adequate. Turn it all back on.
This contains pieces folded in from the fixes made to the original patches
| From: Geert Uytterhoeven <geert@linux-m68k.org> (fix m68k)
| From: Paul Gortmaker <paul.gortmaker@windriver.com> (fix cris)
| From: Jiri Kosina <jkosina@suze.cz> (lockdep)
| From: Eric Dumazet <eric.dumazet@gmail.com> (lockdep)
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We sometimes pass NULL pointers to free_tty_struct(). One example where
it can happen is in the error handling code in pty_common_install().
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We're trying to save the termios state and we need to allocate a buffer
to do it. Smatch complains that the buffer is leaked at the end of the
function.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Ian Abbott found that the tty layer would explode with the right set of
parallel open and close operations. This is because we race in the
handling of tty->drivers->termios[].
Correct this by
Making tty_ldisc_release behave like nromal code (takes the lock,
does stuff, drops the lock)
Drop the tty lock earlier in tty_ldisc_release
Taking the tty mutex around the driver->termios update in all cases
Adding a WARN_ON to catch future screwups.
I also forgot to clean up the pty resources properly. With a pty pair we
need to pull both halves out of the tables.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Tested-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Now that we don't have tty->termios tied to drivers->tty we can untangle
the logic here. In addition we can push the removal logic out of the
destructor path.
At that point we can think about sorting out tty_port and console and all
the other ugly hangovers.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This will let us sort out a whole pile of tty related races. The
alternative would be to keep points and refcount the termios objects.
However
1. They are tiny anyway
2. Many devices don't use the stored copies
3. We can remove a pty special case
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
I sent GregKH this after the pre-requisites. He dropped the pre-requesites
for good reason and unfortunately then applied this patch. Without this
reverted you get random kernel memory corruption which will make bisecting
anything between it and the properly applied patches a complete sod.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The termios and other changes mean the other protections needed on the driver
tty arrays should be adequate. Turn it all back on.
This contains pieces folded in from the fixes made to the original patches
| From: Geert Uytterhoeven <geert@linux-m68k.org> (fix m68k)
| From: Paul Gortmaker <paul.gortmaker@windriver.com> (fix cris)
| From: Jiri Kosina <jkosina@suze.cz> (lockdep)
| From: Eric Dumazet <eric.dumazet@gmail.com> (lockdep)
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
It will hold tty_port structures for all drivers which do not want to
define tty->ops->install hook.
We ignore PTY here because it wants 1 million lines and it installs
tty_port in ->install anyway.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently, some failures are handled in if's false branches, some at
the end of tty_register_driver via goto-labels. Let us handle the
failures at the end of the functions to have the failure handling at
a single place. The only thing needed is to label the lines properly
and jump there.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts the tty layer change to use per-tty locking, because it's
not correct yet, and fixing it will require some more deep surgery.
The main revert is d29f3ef39b ("tty_lock: Localise the lock"), but
there are several smaller commits that built upon it, they also get
reverted here. The list of reverted commits is:
fde86d3108 - tty: add lockdep annotations
8f6576ad47 - tty: fix ldisc lock inversion trace
d3ca8b64b9 - pty: Fix lock inversion
b1d679afd7 - tty: drop the pty lock during hangup
abcefe5fc3 - tty/amiserial: Add missing argument for tty_unlock()
fd11b42e35 - cris: fix missing tty arg in wait_event_interruptible_tty call
d29f3ef39b - tty_lock: Localise the lock
The revert had a trivial conflict in the 68360serial.c staging driver
that got removed in the meantime.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In each remaining case the tty_lock is associated with a specific tty. This
means we can now lock on a per tty basis. We do need tty_lock_pair() for
the pty case. Uglier but still a step in the right direction.
[fixed up calls in 3 missing drivers - gregkh]
Signed-off-by: Alan Cox <alan@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
get_current_tty has its own consistent locking. That means a pile of the
tty lock cases are not needed. As get_current_tty also keeps a reference the
tty object lifetime means we can propogate the lock removal out.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Remove all #inclusions of asm/system.h preparatory to splitting and killing
it. Performed with the following command:
perl -p -i -e 's!^#\s*include\s*<asm/system[.]h>.*\n!!' `grep -Irl '^#\s*include\s*<asm/system[.]h>' *`
Signed-off-by: David Howells <dhowells@redhat.com>
This is from tty_reopen:
struct tty_driver *driver = tty->driver;
...
tty->driver = driver;
and it doesn't make sense at all. The driver is intended to be set in
initialize_tty_struct from tty_init_dev (initial open). So this set in
tty_reopen is not needed.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Remove the useless local variable and return the value itself.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Like the rest of the kernel, make a stub from alloc_tty_driver which
calls __alloc_tty_driver with proper owner. This will save us one more
assignment on the driver side.
Also this fixes some drivers which didn't set the owner. This allowed
user to remove the module from the system even though a tty from the
driver is still open.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
TTY buffer head and tail are initialized in tty_buffer_init. No need
to do it once again in initialize_tty_struct where tty_buffer_init is
called.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit d3bda5298a.
Sasha reported that this causes problems, so revert it.
Cc: Sasha Levin <levinsasha928@gmail.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
devpts operations are protected by inode mutexes and dentry
refcounting. There is no need to hold BTM.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
There are currently many cut&paste copies of what
tty_driver_install_tty does when custom ->install method is not
provided. Let's get rid of the copies and create a helper with this
setup code.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Havard Skinnemoen <hskinnemoen@google.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
cleanup hack added in v2.6.27-3203-g15582d3
comment from that patch:
: 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>
devpts_get_tty() returns non-null only for inodes on devpts, but there is no
inodes for master-devices, /dev/ptmx (/dev/pts/ptmx) is the only way to open them.
Thus we can completely forbid lookup for master-devices and eliminate that hack in
tty_init_dev() because tty_open() will get EIO from tty_driver_lookup_tty().
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* 'tty-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (65 commits)
tty: serial: imx: move del_timer_sync() to avoid potential deadlock
imx: add polled io uart methods
imx: Add save/restore functions for UART control regs
serial/imx: let probing fail for the dt case without a valid alias
serial/imx: propagate error from of_alias_get_id instead of using -ENODEV
tty: serial: imx: Allow UART to be a source for wakeup
serial: driver for m32 arch should not have DEC alpha errata
serial/documentation: fix documented name of DCD cpp symbol
atmel_serial: fix spinlock lockup in RS485 code
tty: Fix memory leak in virtual console when enable unicode translation
serial: use DIV_ROUND_CLOSEST instead of open coding it
serial: add support for 400 and 800 v3 series Titan cards
serial: bfin-uart: Remove ASYNC_CTS_FLOW flag for hardware automatic CTS.
serial: bfin-uart: Enable hardware automatic CTS only when CTS pin is available.
serial: make FSL errata depend on 8250_CONSOLE, not just 8250
serial: add irq handler for Freescale 16550 errata.
serial: manually inline serial8250_handle_port
serial: make 8250 timeout use the specified IRQ handler
serial: export the key functions for an 8250 IRQ handler
serial: clean up parameter passing for 8250 Rx IRQ handling
...
both callers of device_get_devnode() are only interested in lower 16bits
and nobody tries to return anything wider than 16bit anyway.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
There is no need to taint the tty_release code with paranoia
checking. So move it out of line to a separate function. Making thus
tty_release more readable.
[v2] don't introduce a hard to reproduce use after free (scheduled work would
need to preempt the current thread)
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The labels express more the nature of the decision tree. We returned
from each if with a driver. Now we do this at the end of the function
and the code flow is clear.
While at it, remove an obsolete comment (we already take the
reference).
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Move them to the end of the function and use gotos as usual.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The error handling in tty_open became unbearable. There were many
errors fixed recently. Extract the tty driver lookup from tty_open to
a separate function. This reduces the fail paths significantly and
makes tty_open more readable.
In the next patch we will move the fail path handling to the end of
the function.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This one is special to others (done in the next patch). We have the
tty directly, not its driver and index. So this will reside in a
separation function. In the next patch, the rest will be moved to
another function.
So now we set neither driver nor index. Hence we need to init driver
and check whether we are supposed to put a ref of that.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Move it to the only branch where tty_pgrp may be set. This is only a
cleanup which allows having tty_pgrp defined at that place.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* 'tty-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (79 commits)
TTY: serial_core: Fix crash if DCD drop during suspend
tty/serial: atmel_serial: bootconsole removed from auto-enumerates
Revert "TTY: call tty_driver_lookup_tty unconditionally"
tty/serial: atmel_serial: add device tree support
tty/serial: atmel_serial: auto-enumerate ports
tty/serial: atmel_serial: whitespace and braces modifications
tty/serial: atmel_serial: change platform_data variable name
tty/serial: RS485 bindings for device tree
TTY: call tty_driver_lookup_tty unconditionally
TTY: pty, release tty in all ptmx_open fail paths
TTY: make tty_add_file non-failing
TTY: drop driver reference in tty_open fail path
8250_pci: Fix kernel panic when pch_uart is disabled
h8300: drivers/serial/Kconfig was moved
parport_pc: release IO region properly if unsupported ITE887x card is found
tty: Support compat_ioctl get/set termios_locked
hvc_console: display printk messages on console.
TTY: snyclinkmp: forever loop in tx_load_dma_buffer()
tty/n_gsm: avoid fifo overflow in gsm_dlci_data_output
tty/n_gsm: fix a bug in gsm_dlci_data_output (adaption = 2 case)
...
Fix up Conflicts in:
- drivers/tty/serial/8250_pci.c
Trivial conflict with removed duplicate device ID
- drivers/tty/serial/atmel_serial.c
Annoying silly conflict between "specify the port num via
platform_data" and other changes to atmel_console_init
Commit 4a2b5fddd5 (Move tty lookup/reopen to caller) made the call to
tty_driver_lookup_tty conditional in tty_open. It doesn't look like it
was an intention. Or if it was, it was not documented in the changelog
and the code now looks weird. For example there would be no need to
remember the tty driver and tty index. Further the condition depends
on a tty which we drop a reference of already.
If I'm looking correctly, this should not matter thanks to the locking
currently done there. Thus, tty_driver->ttys[idx] cannot change under
our hands. But anyway, it makes sense to change that to the old
behaviour.
Introduced-in: v2.6.28-rc2
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: stable <stable@vger.kernel.org>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Alan Cox <alan@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
If tty_add_file fails at the point it is now, we have to revert all
the changes we did to the tty. It means either decrease all refcounts
if this was a tty reopen or delete the tty if it was newly allocated.
There was a try to fix this in v3.0-rc2 using tty_release in 0259894c7
(TTY: fix fail path in tty_open). But instead it introduced a NULL
dereference. It's because tty_release dereferences
filp->private_data, but that one is set even in our tty_add_file. And
when tty_add_file fails, it's still NULL/garbage. Hence tty_release
cannot be called there.
To circumvent the original leak (and the current NULL deref) we split
tty_add_file into two functions, making the latter non-failing. In
that case we may do the former early in open, where handling failures
is easy. The latter stays as it is now. So there is no change in
functionality.
The original bug (leak) was introduced by f573bd176 (tty: Remove
__GFP_NOFAIL from tty_add_file()). Thanks Dan for reporting this.
Later, we may split tty_release into more functions and call only some
of them in this fail path instead. (If at all possible.)
Introduced-in: v2.6.37-rc2
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: stable <stable@vger.kernel.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
When tty_driver_lookup_tty fails in tty_open, we forget to drop a
reference to the tty driver. This was added by commit 4a2b5fddd5 (Move
tty lookup/reopen to caller).
Fix that by adding tty_driver_kref_put to the fail path.
I will refactor the code later. This is for the ease of backporting to
stable.
Introduced-in: v2.6.28-rc2
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: stable <stable@vger.kernel.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Acked-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
When running a Fedora 15 (x86) on an x86_64 kernel, in the boot process
plymouthd complains about those two missing ioctls:
[ 2.581783] ioctl32(plymouthd:186): Unknown cmd fd(10) cmd(00005457){t:'T';sz:0} arg(ffb6a5d0) on /dev/tty1
[ 2.581803] ioctl32(plymouthd:186): Unknown cmd fd(10) cmd(00005456){t:'T';sz:0} arg(ffb6a680) on /dev/tty1
both ioctl functions work on the 'struct termios' resp. 'struct termios2',
which has the same size (36 bytes resp. 44 bytes) on x86 and x86_64,
so it's just a matter of converting the pointer from userland.
Signed-off-by: Thomas Meyer <thomas@m3y3r.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
tty_operations->remove is normally called like:
queue_release_one_tty
->tty_shutdown
->tty_driver_remove_tty
->tty_operations->remove
However tty_shutdown() is called from queue_release_one_tty() only if
tty_operations->shutdown is NULL. But for pty, it is not.
pty_unix98_shutdown() is used there as ->shutdown.
So tty_operations->remove of pty (i.e. pty_unix98_remove()) is never
called. This results in invalid pty_count. I.e. what can be seen in
/proc/sys/kernel/pty/nr.
I see this was already reported at:
https://lkml.org/lkml/2009/11/5/370
But it was not fixed since then.
This patch is kind of a hackish way. The problem lies in ->install. We
allocate there another tty (so-called tty->link). So ->install is
called once, but ->remove twice, for both tty and tty->link. The fix
here is to count both tty and tty->link and divide the count by 2 for
user.
And to have ->remove called, let's make tty_driver_remove_tty() global
and call that from pty_unix98_shutdown() (tty_operations->shutdown).
While at it, let's document that when ->shutdown is defined,
tty_shutdown() is not called.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Peter Hurley