linux-stable.git/drivers/tty/tty_io.c, branch v3.18

tty: Prevent "read/write wait queue active!" log flooding

2014-11-06T00:14:09+00:00

Only print one warning when a task is on the read_wait or write_wait
wait queue at final tty release.

Cc:  # 3.4.x+
Signed-off-by: Peter Hurley 
Signed-off-by: Greg Kroah-Hartman

tty: Fix high cpu load if tty is unreleaseable

2014-11-06T00:14:09+00:00

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:  # since before 2.6.32
Signed-off-by: Peter Hurley 
Signed-off-by: Greg Kroah-Hartman

Merge tag 'locks-v3.18-1' of git://git.samba.org/jlayton/linux

2014-10-11T17:21:34+00:00

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
  ...

tty: Move and rename send_prio_char() as tty_send_xchar()

2014-09-24T04:19:35+00:00

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 
Signed-off-by: Greg Kroah-Hartman

tty: Move packet mode flow control notifications to pty driver

2014-09-24T04:19:35+00:00

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 
Signed-off-by: Greg Kroah-Hartman

tty: Serialize tty flow control changes with flow_lock

2014-09-24T04:19:35+00:00

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 
Signed-off-by: Greg Kroah-Hartman

security: make security_file_set_fowner, f_setown and __f_setown void return

2014-09-09T20:01:36+00:00

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 
Reviewed-by: Christoph Hellwig

tty: Fix potential use after free in release_one_tty

2014-09-08T22:55:25+00:00

In case if we're releasing the last tty reference the following
call sequence is possible

tty_driver_kref_put
  destruct_tty_driver
    kfree(driver);

where @driver is used in next module_put call, which leads to

 | [ 285.964007] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
 | [ 285.964007] Workqueue: events release_one_tty
 | [ 285.964007] task: ffff8800cc7ea5f0 ti: ffff8800cb800000 task.ti: ffff8800cb800000
 | [ 285.964007] RIP: 0010:[] [] module_put+0x24/0xf4
 | [ 285.964007] RSP: 0018:ffff8800cb801d48 EFLAGS: 00010213
 | [ 285.964007] RAX: ffff8800cb801fd8 RBX: ffff8800ca3429d0 RCX: ffff8800cb1db400
 | [ 285.964007] RDX: 0000000000000000 RSI: ffffffff817349c1 RDI: 0000000000000001
 | [ 285.964007] RBP: ffff8800cb801d60 R08: ffff8800cd632b40 R09: 0000000000000000
 | [ 285.964007] R10: 00000000ffffffff R11: ffff88011f40a000 R12: 6b6b6b6b6b6b6b6b
 | [ 285.964007] R13: ffff8800ca342520 R14: 0000000000000000 R15: ffff88011f5d8200
 | [ 285.964007] FS: 0000000000000000(0000) GS:ffff88011f400000(0000) knlGS:0000000000000000
 | [ 285.964007] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
 | [ 285.964007] CR2: 00007faf5229d090 CR3: 0000000001c0b000 CR4: 00000000000006f0
 | [ 285.964007] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 | [ 285.964007] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
 | [ 285.964007] Stack:
 | [ 285.964007] ffff8800ca3429d0 ffff8800ca342a30 ffff8800ca342520 ffff8800cb801d88
 | [ 285.964007] ffffffff8146554a ffff8800cc77cc78 ffff8800ca3429d0 ffff88011f5d3800
 | [ 285.964007] ffff8800cb801e08 ffffffff810683c1 ffffffff810682ff 0000000000000046
 | [ 285.964007] Call Trace:
 | [ 285.964007] [] release_one_tty+0x54/0xa3
 | [ 285.964007] [] process_one_work+0x223/0x404
 | [ 285.964007] [] ? process_one_work+0x161/0x404
 | [ 285.964007] [] worker_thread+0x136/0x205
 | [ 285.964007] [] ? rescuer_thread+0x26a/0x26a
 | [ 285.964007] [] kthread+0xa2/0xaa
 | [ 285.964007] [] ? trace_hardirqs_on_caller+0x16/0x1eb
 | [ 285.964007] [] ? __kthread_parkme+0x65/0x65
 | [ 285.964007] [] ret_from_fork+0x7c/0xb0
 | [ 285.964007] [] ? __kthread_parkme+0x65/0x65
 | [ 285.964007] Code: 09 00 5b 41 5c 5d c3 0f 1f 44 00 00 55 48 85 ff 48 89 e5 41 55 41 54 49 89 fc 53 0f 84 d3 00
 | 00 00 bf 01 00 00 00 e8 d0 a1 fc ff <49> 8b 84 24 50 02 00 00 65 48 ff 40 08 4c 8b 6d 08 0f 1f 44 00

so simply keep a local reference to the module owner and
use it later.

CC: Pavel Emelyanov 
CC: Jiri Slaby 
CC: Greg Kroah-Hartman 
Signed-off-by: Cyrill Gorcunov 
Signed-off-by: Greg Kroah-Hartman

drivers: tty: Merge alloc_tty_struct and initialize_tty_struct

2014-07-12T00:54:28+00:00

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 
Signed-off-by: Greg Kroah-Hartman

tty: Call hangup method in modern style

2014-07-10T23:07:46+00:00

Signed-off-by: Peter Hurley 
Signed-off-by: Greg Kroah-Hartman