linux-stable.git/drivers/tty/pty.c, branch v3.1 Linux kernel stable tree TTY: pty, fix pty counting 2011-08-23T17:10:38+00:00 Jiri Slaby jslaby@suse.cz 2011-08-10T12:59:28+00:00 24d406a6bf736f7aebdc8fa0f0ec86e0890c6d24 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> 
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>
tty: remove invalid location line in file header 2011-04-19T23:33:36+00:00 Jovi Zhang bookjovi@gmail.com 2011-03-30T09:30:41+00:00 99edb3d10a9d384d69557bd09cc39b9ec62aa04e remove invalid location line in each file header after location moved from driver/char to driver/tty Signed-off-by: Jovi Zhang <bookjovi@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> 
remove invalid location line in each file header after location
moved from driver/char to driver/tty

Signed-off-by: Jovi Zhang <bookjovi@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
TTY: plug in deinitialize_tty_struct 2011-04-19T21:43:01+00:00 Jiri Slaby jslaby@suse.cz 2011-03-23T09:48:36+00:00 a9dccddb60913056bcadaeeacfe0395447fd2472 Used the newly introduced deinitialize_tty_struct to properly shut down ldisc. It is intended to fix the Julian's reported problem. He reports that kmemleak checker warns about memory leak: unreferenced object 0xc0e19860 (size 8): comm cat, pid 1226, jiffies 4294919464 (age 287.476s) hex dump (first 8 bytes): 44 de 2d c1 01 00 00 00 D.-..... backtrace: [<c1065a74>] create_object+0x109/0x1ad [<c1063d2b>] kmem_cache_alloc+0x60/0x68 [<c113505c>] tty_ldisc_get+0x54/0x76 [<c11358c9>] tty_ldisc_init+0xa/0x20 [<c1130ab4>] initialize_tty_struct+0x2d/0x1ac [<c1130c8c>] tty_init_dev+0x59/0x10d [<c113136d>] tty_open+0x24a/0x3a2 ... Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Reported-by: Julian Anastasov <ja@ssi.bg> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> 
Used the newly introduced deinitialize_tty_struct to properly shut
down ldisc.

It is intended to fix the Julian's reported problem. He reports that
kmemleak checker warns about memory leak:
unreferenced object 0xc0e19860 (size 8):
comm cat, pid 1226, jiffies 4294919464 (age 287.476s)
hex dump (first 8 bytes):
44 de 2d c1 01 00 00 00 D.-.....
backtrace:
[<c1065a74>] create_object+0x109/0x1ad
[<c1063d2b>] kmem_cache_alloc+0x60/0x68
[<c113505c>] tty_ldisc_get+0x54/0x76
[<c11358c9>] tty_ldisc_init+0xa/0x20
[<c1130ab4>] initialize_tty_struct+0x2d/0x1ac
[<c1130c8c>] tty_init_dev+0x59/0x10d
[<c113136d>] tty_open+0x24a/0x3a2
...

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Reported-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
TTY: unify pty_unix98_install fail path handling 2011-04-19T21:43:00+00:00 Jiri Slaby jslaby@suse.cz 2011-03-23T09:48:34+00:00 c18d77aa00cde1215d9e045ba8f93004fe843f38 Change it so that we call the deinit functions at one place at the end of the function (by gotos). And while at it use some sane label names. This is a preparation for the deinitialization of tty in the next patch. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Julian Anastasov <ja@ssi.bg> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> 
Change it so that we call the deinit functions at one place at the end
of the function (by gotos). And while at it use some sane label names.

This is a preparation for the deinitialization of tty in the next
patch.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
TTY: unify pty_install fail path handling 2011-04-19T21:43:00+00:00 Jiri Slaby jslaby@suse.cz 2011-03-23T09:48:33+00:00 8a1b8d70a07628f294f30485acf81971e3fcc755 Change it so that we call the deinit functions at one place at the end of the function (by gotos). And while at it use some sane label names. This is a preparation for the deinitialization of tty in the next patch. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Julian Anastasov <ja@ssi.bg> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> 
Change it so that we call the deinit functions at one place at the end
of the function (by gotos). And while at it use some sane label names.

This is a preparation for the deinitialization of tty in the next
patch.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Merge branch 'config' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl 2011-03-17T00:21:00+00:00 Linus Torvalds torvalds@linux-foundation.org 2011-03-17T00:21:00+00:00 f74b9444192c60603020c61d7915b72893137edc * 'config' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl: BKL: That's all, folks fs/locks.c: Remove stale FIXME left over from BKL conversion ipx: remove the BKL appletalk: remove the BKL x25: remove the BKL ufs: remove the BKL hpfs: remove the BKL drivers: remove extraneous includes of smp_lock.h tracing: don't trace the BKL adfs: remove the big kernel lock 
* 'config' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bkl:
  BKL: That's all, folks
  fs/locks.c: Remove stale FIXME left over from BKL conversion
  ipx: remove the BKL
  appletalk: remove the BKL
  x25: remove the BKL
  ufs: remove the BKL
  hpfs: remove the BKL
  drivers: remove extraneous includes of smp_lock.h
  tracing: don't trace the BKL
  adfs: remove the big kernel lock
drivers: remove extraneous includes of smp_lock.h 2011-03-01T23:02:40+00:00 Arnd Bergmann arnd@arndb.de 2011-01-25T21:08:05+00:00 5edc341313a188d94cde7ef87ac31647cea8601a These were missed the last time I cleaned this up globally, because of code moving around or new code getting merged. Signed-off-by: Arnd Bergmann <arnd@arndb.de> 
These were missed the last time I cleaned this up
globally, because of code moving around or new code
getting merged.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
tty: now phase out the ioctl file pointer for good 2011-02-17T19:59:56+00:00 Alan Cox alan@linux.intel.com 2011-02-14T16:27:22+00:00 6caa76b7786891b42b66a0e61e2c2fff2c884620 Only oddities here are a couple of drivers that bogusly called the ldisc helpers instead of returning -ENOIOCTLCMD. Fix the bug and the rest goes away. Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> 
Only oddities here are a couple of drivers that bogusly called the ldisc
helpers instead of returning -ENOIOCTLCMD. Fix the bug and the rest goes
away.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
TTY: create drivers/tty and move the tty core files there 2010-11-05T15:10:33+00:00 Greg Kroah-Hartman gregkh@suse.de 2010-11-04T18:10:29+00:00 96fd7ce58ffb5c7bf376796b5525ba3ea1c9d69f The tty code should be in its own subdirectory and not in the char driver with all of the cruft that is currently there. Based on work done by Arnd Bergmann <arnd@arndb.de> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> 
The tty code should be in its own subdirectory and not in the char
driver with all of the cruft that is currently there.

Based on work done by Arnd Bergmann <arnd@arndb.de>

Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>