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path: root/drivers/tty/pty.c
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2012-08-10tty: localise the lockAlan Cox1-11/+14
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>
2012-07-27tty: Fix race in tty releaseAlan Cox1-2/+23
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>
2012-07-17tty: Move the handling of the tty release logicAlan Cox1-10/+2
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>
2012-07-16tty: move the termios object into the ttyAlan Cox1-17/+6
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>
2012-07-16tty: revert incorrectly applied lock patchAlan Cox1-12/+11
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>
2012-07-12tty: double unlock on error in ptmx_open()Dan Carpenter1-3/+1
The problem here is that we called mutex_unlock(&devpts_mutex) on the error path when we weren't holding the lock. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-07-06tty: localise the lockAlan Cox1-11/+14
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>
2012-06-13PTY: add tty_portJiri Slaby1-4/+21
This has *no* function in the PTY driver yet. However as the tty buffers will move to the tty_port structure, we will need tty_port for all TTYs in the system, PTY inclusive. For PTYs this is ensured by allocating 2 tty_port's in pty_install, i.e. where the tty->link is allocated. Both tty_port's are properly assigned to each end of the tty. Freeing is done at the same place where tty is freed, i.e. in tty->ops->cleanup. This means BTW that tty_port does not outlive TTY in PTY. This might be a subject to change in the future if we see some problems. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-06-13PTY: merge pty_install implementationsJiri Slaby1-65/+45
There are currently two instances of code which handles PTY install. One for the legacy BSD PTY's, one for unix98's PTY's. Both of them are very similar and differ only in termios allocation and handling. Since we will need to allocate a tty_port at that place, this would require editing two places with the same pattern. Instead, let us move the implementation to one common place and call it from both places. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-06-13PTY: remove one empty ops->removeJiri Slaby1-7/+3
Currently, there are two as a left-over from previous patches. Although we really need to provide an empty handler, we do not need two. So remove one of them. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-06-02tty: Revert the tty locking series, it needs more workLinus Torvalds1-14/+11
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 d29f3ef39be4 ("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: fde86d310886 - tty: add lockdep annotations 8f6576ad476b - tty: fix ldisc lock inversion trace d3ca8b64b97e - pty: Fix lock inversion b1d679afd766 - tty: drop the pty lock during hangup abcefe5fc357 - tty/amiserial: Add missing argument for tty_unlock() fd11b42e3598 - cris: fix missing tty arg in wait_event_interruptible_tty call d29f3ef39be4 - 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>
2012-05-29pty: Fix lock inversionAlan Cox1-2/+0
The ptmx_open path takes the tty and devpts locks in the wrong order because tty_init_dev locks and returns a locked tty. As far as I can tell this is actually safe anyway because the tty being returned is new so nobody can get a reference to lock it at this point. However we don't even need the devpts lock at this point, it's only held as a byproduct of the way the locks were pushe down. Signed-off-by: Alan Cox <alan@linux.intel.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-09tty: drop the pty lock during hangupAlan Cox1-0/+2
In theory we don't need it, in practice we are hitting some ill understood deadlock when we don't drop it. The old code dropped it here so we are not undoing anything problematic for pty. If pty could be unloaded it would be a problem but it can't. Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-05-04tty_lock: Localise the lockAlan Cox1-10/+13
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>
2012-05-04pty: Lock the devpts bits privatelyAlan Cox1-4/+15
This is a private pty affair, we don't want to tangle it with the tty_lock any more as we know all the other non tty locking is now handled by the vfs so we too can move. Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-03-28Remove all #inclusions of asm/system.hDavid Howells1-1/+0
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>
2012-03-08TTY: remove re-assignments to tty_driver membersJiri Slaby1-4/+0
All num, magic and owner are set by alloc_tty_driver. No need to re-set them on each allocation site. pti driver sets something different to what it passes to alloc_tty_driver. It is not a bug, since we don't use the lines parameter in any way. Anyway this is fixed, and now we do the right thing. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Acked-by: Tilman Schmidt <tilman@imap.cc> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-02-24Revert "TTY: pty, remove superfluous ptm test"Greg Kroah-Hartman1-1/+4
This reverts commit a50f724a432997321cabb6c9e665c28e34850f78. Sasha reported that this causes problems, so revert it. Cc: Alan Cox <alan@linux.intel.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Sasha Levin <levinsasha928@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-02-24Revert "TTY: get rid of BTM around devpts_*"Greg Kroah-Hartman1-2/+4
This reverts commit d3bda5298aad98c7a27678bdd0dd9d008ab9e685. 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>
2012-02-02TTY: get rid of BTM around devpts_*Jiri Slaby1-4/+2
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>
2012-02-02TTY: pty, remove superfluous ptm testJiri Slaby1-4/+1
The code looks like: if (tty->driver->subtype == PTY_TYPE_MASTER) { ... if (tty->driver == ptm_driver) But the second if is superfluous because only the ptm_driver is of PTY_TYPE_MASTER subtype. Also we can remove the #if now because devpts_pty_kill is defined as an empty function for non-CONFIG_UNIX98_PTYS configs. 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>
2012-01-24tty: move pty count limiting into devptsKonstantin Khlebnikov1-51/+0
Let's move this stuff to the better place, where we can account pty right in tty-indexes managing code. Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2012-01-24tty: cleanup prohibition of direct opening for unix98 pty masterKonstantin Khlebnikov1-5/+3
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>
2011-11-17TTY: pty, cleanup the pty countingJiri Slaby1-17/+9
Instead of the hackish way of counting ptys, let's define a specific ->remove hook both from slave and master. And decrease the count only for master. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-10-26Merge branch 'tty-next' of ↵Linus Torvalds1-10/+16
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty * '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
2011-10-18TTY: pty, release tty in all ptmx_open fail pathsJiri Slaby1-5/+5
Mistakenly, commit 64ba3dc3143d (tty: never hold BTM while getting tty_mutex) switched one fail path in ptmx_open to not free the newly allocated tty. Fix that by jumping to the appropriate place. And rename the labels so that it's clear what is going on there. Introduced-in: v2.6.36-rc2 Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: stable <stable@vger.kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-10-18TTY: make tty_add_file non-failingJiri Slaby1-5/+11
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>
2011-08-23TTY: pty, fix pty countingJiri Slaby1-2/+15
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>
2011-04-19tty: remove invalid location line in file headerJovi Zhang1-2/+0
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>
2011-04-19TTY: plug in deinitialize_tty_structJiri Slaby1-2/+4
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>
2011-04-19TTY: unify pty_unix98_install fail path handlingJiri Slaby1-6/+6
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>
2011-04-19TTY: unify pty_install fail path handlingJiri Slaby1-9/+10
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>
2011-03-16Merge branch 'config' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/bklLinus Torvalds1-1/+0
* '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
2011-03-02drivers: remove extraneous includes of smp_lock.hArnd Bergmann1-1/+0
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>
2011-02-17tty: now phase out the ioctl file pointer for goodAlan Cox1-2/+2
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>
2010-11-05TTY: create drivers/tty and move the tty core files thereGreg Kroah-Hartman1-0/+777
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>
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