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path: root/drivers/tty/tty_io.c
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* devpts: more pty driver interface cleanupsLinus Torvalds2016-04-261-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is more prep-work for the upcoming pty changes. Still just code cleanup with no actual semantic changes. This removes a bunch pointless complexity by just having the slave pty side remember the dentry associated with the devpts slave rather than the inode. That allows us to remove all the "look up the dentry" code for when we want to remove it again. Together with moving the tty pointer from "inode->i_private" to "dentry->d_fsdata" and getting rid of pointless inode locking, this removes about 30 lines of code. Not only is the end result smaller, it's simpler and easier to understand. The old code, for example, depended on the d_find_alias() to not just find the dentry, but also to check that it is still hashed, which in turn validated the tty pointer in the inode. That is a _very_ roundabout way to say "invalidate the cached tty pointer when the dentry is removed". The new code just does dentry->d_fsdata = NULL; in devpts_pty_kill() instead, invalidating the tty pointer rather more directly and obviously. Don't do something complex and subtle when the obvious straightforward approach will do. The rest of the patch (ie apart from code deletion and the above tty pointer clearing) is just switching the calling convention to pass the dentry or file pointer around instead of the inode. Cc: Eric Biederman <ebiederm@xmission.com> Cc: Peter Anvin <hpa@zytor.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: Serge Hallyn <serge.hallyn@ubuntu.com> Cc: Willy Tarreau <w@1wt.eu> Cc: Aurelien Jarno <aurelien@aurel32.net> Cc: Alan Cox <gnomes@lxorguk.ukuu.org.uk> Cc: Jann Horn <jann@thejh.net> Cc: Greg KH <greg@kroah.com> Cc: Jiri Slaby <jslaby@suse.com> Cc: Florian Weimer <fw@deneb.enyo.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tty: Fix merge of "tty: Refactor tty_open()"Peter Hurley2016-03-311-2/+1
| | | | | | | | | | | | | Commit e9036d066236 ("tty: Drop krefs for interrupted tty lock") fixed a tty reference counting problem introduced in commit 0bfd464d3fdd ("tty: Wait interruptibly for tty lock on reopen"), so v4.5.0 is correct. However, commit d6203d0c7b73 ("tty: Refactor tty_open()") moved the relevant code for 4.6-rc1; correct the merge. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Fix UML console breakagePeter Hurley2016-03-311-1/+1
| | | | | | | | | | | User-Mode Linux supplies an alternate TTY_MAJOR driver for stdio console, so the noctty check in tty_open() must apply only to VT driver tty0 devnode and not the UML console driver tty0 devnode. Fixes: 11e1d4aa4da1 ("tty: Consolidate noctty checks in tty_open()") Reported-by: Richard Weinberger <richard.weinberger@gmail.com> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Fix ioctl(FIOASYNC) on hungup filePeter Hurley2016-01-281-2/+3
| | | | | | | | | | | | | | | | | | | | | | | A small race window exists which allows signal-driven async i/o to be enabled for the tty when the file ptr has already been hungup and signal-driven i/o has been disabled: CPU 0 CPU 1 ----- ------ ioctl_fioasync(on) filp->f_op->fasync(on) __tty_hangup() tty_fasync(on) tty_lock() tty_lock() ... . filp->f_op = &hung_up_tty_fops; (waiting) __tty_fasync(off) . tty_unlock() /* gets tty lock */ /* enables FASYNC */ Check the tty has not been hungup while holding tty_lock. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Add fasync() hung up file operationPeter Hurley2016-01-281-0/+6
| | | | | | | | | | | | | VFS uses a two-stage check-and-call method for invoking file_operations methods, without explicitly snapshotting either the file_operations ptr or the function ptr. Since the tty core is one of the few VFS users that changes the f_op file_operations ptr of the file descriptor (when the tty has been hung up), and since the likelihood of the compiler generating a reload of either f_op or the function ptr is basically nil, just define a hung up fasync() file operation that returns an error. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty, n_tty: Remove fasync() ldisc notificationPeter Hurley2016-01-281-8/+0
| | | | | | | | | | | | | | | | | | | | | | | Only the N_TTY line discipline implements the signal-driven i/o notification enabled/disabled by fcntl(F_SETFL, O_ASYNC). The ldisc fasync() notification is sent to the ldisc when the enable state has changed (the tty core is notified via the fasync() VFS file operation). The N_TTY line discipline used the enable state to change the wakeup condition (minimum_to_wake = 1) for notifying the signal handler i/o is available. However, just the presence of data is sufficient and necessary to signal i/o is available, so changing minimum_to_wake is unnecessary (and creates a race condition with read() and poll() which may be concurrently updating minimum_to_wake). Furthermore, since the kill_fasync() VFS helper performs no action if the fasync list is empty, calling unconditionally is preferred; if signal driven i/o just has been disabled, no signal will be sent by kill_fasync() anyway so notification of the change via the ldisc fasync() method is superfluous. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Make tty_files_lock per-ttyPeter Hurley2016-01-271-13/+12
| | | | | | | | | | Access to tty->tty_files list is always per-tty, never for all ttys simultaneously. Replace global tty_files_lock spinlock with per-tty ->files_lock. Initialize when the ->tty_files list is inited, in alloc_tty_struct(). Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Move tty_check_change() helperPeter Hurley2016-01-271-0/+6
| | | | | | | | Move is_ignored() to drivers/tty/tty_io.c and re-declare in file scope. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Eliminate global symbol tty_ldisc_N_TTYPeter Hurley2016-01-271-1/+1
| | | | | | | | Reduce global tty symbols; move and rename tty_ldisc_begin() as n_tty_init() and redefine the N_TTY ldisc ops as file scope. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Unexport system-wide tty_mutexPeter Hurley2016-01-271-3/+1
| | | | | | | | tty_mutex is a core, system-wide lock; there is no reason for any code outside the tty core to have direct access. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Document c_line == N_TTY initial conditionPeter Hurley2016-01-271-1/+2
| | | | | | | | The line discipline id is stored in the tty's termios; document the implicit initial value of N_TTY. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Destroy ldisc instance on hangupPeter Hurley2016-01-271-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, when the tty is hungup, the ldisc is re-instanced; ie., the current instance is destroyed and a new instance is created. The purpose of this design was to guarantee a valid, open ldisc for the lifetime of the tty. However, now that tty buffers are owned by and have lifetime equivalent to the tty_port (since v3.10), any data received immediately after the ldisc is re-instanced may cause continued driver i/o operations concurrently with the driver's hangup() operation. For drivers that shutdown h/w on hangup, this is unexpected and usually bad. For example, the serial core may free the xmit buffer page concurrently with an in-progress write() operation (triggered by echo). With the existing stable and robust ldisc reference handling, the cleaned-up tty_reopen(), the straggling unsafe ldisc use cleaned up, and the preparation to properly handle a NULL tty->ldisc, the ldisc instance can be destroyed and only re-instanced when the tty is re-opened. If the tty was opened as /dev/console or /dev/tty0, the original behavior of re-instancing the ldisc is retained (the 'reinit' parameter to tty_ldisc_hangup() is true). This is required since those file descriptors are never hungup. This patch has neglible impact on userspace; the tty file_operations ptr is changed to point to the hungup file operations _before_ the ldisc instance is destroyed, so only racing file operations might now retrieve a NULL ldisc reference (which is simply handled as if the hungup file operation had been called instead -- see "tty: Prepare for destroying line discipline on hangup"). This resolves a long-standing FIXME and several crash reports. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Use 'disc' for line discipline index namePeter Hurley2016-01-271-3/+3
| | | | | | | | | | tty->ldisc is a ptr to struct tty_ldisc, but unfortunately 'ldisc' is also used as a parameter or local name to refer to the line discipline index value (ie, N_TTY, N_GSM, etc.); instead prefer the name used by the line discipline registration/ref counting functions. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Prepare for destroying line discipline on hangupPeter Hurley2016-01-271-0/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | tty file_operations (read/write/ioctl) wait for the ldisc reference indefinitely (until ldisc lifetime events, such as hangup or TIOCSETD, finish). Since hangup now destroys the ldisc and does not instance another copy, file_operations must now be prepared to receive a NULL ldisc reference from tty_ldisc_ref_wait(): CPU 0 CPU 1 ----- ----- (*f_op->read)() => tty_read() __tty_hangup() ... f_op = &hung_up_tty_fops; ... tty_ldisc_hangup() tty_ldisc_lock() tty_ldisc_kill() tty->ldisc = NULL tty_ldisc_unlock() ld = tty_ldisc_ref_wait() /* ld == NULL */ Instead, the action taken now is to return the same value as if the tty had been hungup a moment earlier: CPU 0 CPU 1 ----- ----- __tty_hangup() ... f_op = &hung_up_tty_fops; (*f_op->read)() => hung_up_tty_read() return 0; ... tty_ldisc_hangup() tty_ldisc_lock() tty_ldisc_kill() tty->ldisc = NULL tty_ldisc_unlock() Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Reset c_line from driver's init_termiosPeter Hurley2016-01-271-2/+3
| | | | | | | | | | | | | After the ldisc is released, but before the tty is destroyed, the termios is saved (in tty_free_termios()); this termios is restored if a new tty is created on next open(). However, the line discipline is always reset, which is not obvious in the current method. Instead, reset as part of the restore. Restore the original line discipline, which may not have been N_TTY. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Refactor tty_open()Peter Hurley2016-01-271-53/+67
| | | | | | | | Extract the driver lookup and reopen-or-initialize logic into helper function tty_open_by_driver(). No functional change. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Consolidate noctty checks in tty_open()Peter Hurley2016-01-271-9/+8
| | | | | | | | Evaluate the conditions which prevent this tty being the controlling terminal in one place, just before setting the controlling terminal. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Re-declare tty_driver_remove_tty() file scopePeter Hurley2016-01-271-1/+1
| | | | | | | tty_driver_remove_tty() is only local-scope; declare as static. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Fix tty_init_termios() declarationPeter Hurley2016-01-271-9/+4
| | | | | | | | | | | tty_init_termios() never returns an error; re-declare as void. Remove unnecessary error handling from callers. Remove extern declarations of tty_free_termios() and free_tty_struct() and re-declare in file scope. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Acked-by: Johan Hovold <johan@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Remove !tty check from free_tty_struct()Peter Hurley2016-01-271-2/+0
| | | | | | | | free_tty_struct() is never called with NULL tty; the two call sites would already have faulted on earlier access. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Fix ldisc leak in failed tty_init_dev()Peter Hurley2016-01-271-17/+3
| | | | | | | | | | | | | | | release_tty() leaks the ldisc instance when called directly (rather than when releasing the file descriptor from tty_release()). Since tty_ldisc_release() clears tty->ldisc, releasing the ldisc instance at tty teardown if tty->ldisc is non-null is not in danger of double-releasing the ldisc. Remove deinitialize_tty_struct() now that free_tty_struct() always performs the tty_ldisc_deinit(). Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Fix unsafe ldisc reference via ioctl(TIOCGETD)Peter Hurley2016-01-261-1/+23
| | | | | | | | | | | | | | | | | | ioctl(TIOCGETD) retrieves the line discipline id directly from the ldisc because the line discipline id (c_line) in termios is untrustworthy; userspace may have set termios via ioctl(TCSETS*) without actually changing the line discipline via ioctl(TIOCSETD). However, directly accessing the current ldisc via tty->ldisc is unsafe; the ldisc ptr dereferenced may be stale if the line discipline is changing via ioctl(TIOCSETD) or hangup. Wait for the line discipline reference (just like read() or write()) to retrieve the "current" line discipline id. Cc: <stable@vger.kernel.org> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Retry failed reopen if tty teardown in-progressPeter Hurley2016-01-261-4/+8
| | | | | | | | | | | | | | | | A small window exists where a tty reopen will observe the tty just prior to imminent teardown (tty->count == 0); in this case, open() returns EIO to userspace. Instead, retry the open after checking for signals and yielding; this interruptible retry loop allows teardown to commence and initialize a new tty on retry. Never retry the BSD master pty reopen; there is no guarantee the pty pair teardown is imminent since the slave file descriptors may remain open indefinitely. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Cc: stable <stable@vger.kernel.org> # 4.4 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Wait interruptibly for tty lock on reopenPeter Hurley2016-01-261-1/+7
| | | | | | | | | | Allow a signal to interrupt the wait for a tty reopen; eg., if the tty has starting final close and is waiting for the device to drain. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Cc: stable <stable@vger.kernel.org> # 4.4 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Only allow slave pty as controlling ttyPeter Hurley2015-12-131-1/+1
| | | | | | | | | A master pty should never be a controlling tty in Linux; if the master pty is specified to ioctl(TIOCSCTTY), silently substitute the slave pty as the controlling tty. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: core: Prefer dev_dbg() over pr_debug()Peter Hurley2015-12-131-1/+1
| | | | | | | Where possible, use dev_dbg() instead of pr_debug() Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Remove __func__ from tty_debug() macroPeter Hurley2015-12-131-7/+7
| | | | | | | | | | | | | Now that tty_debug() macro uses pr_debug(), the function name can be printed when using dynamic debug; printing the function name within the format string is redundant. Remove the __func__ parameter and print specifier from the format string. Add context to messages for when the function name is not printed by dynamic debug, or when dynamic debug is not enabled. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: core: Prefer pr_* to printk(*)Peter Hurley2015-12-131-4/+2
| | | | | | | | Convert remaining printk() use to pr_*() when tty is unknown or unsafe to use. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: core: Add driver name to invalid device registration messagePeter Hurley2015-12-131-2/+2
| | | | | | | | | | | Include the driver name in the tty_register_device_attr() error message for invalid index. Note that tty_err() cannot be used here because there is no tty; use pr_err(). Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Convert SAK messages to tty_notice()Peter Hurley2015-12-131-12/+8
| | | | | | | | Use tty_notice() for unified message format from the tty core. Fix each message to accurately reflect the cause of each termination. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Define tty_*() printk macrosPeter Hurley2015-12-131-17/+10
| | | | | | | | | | | | | Since not all ttys are devices (eg., SysV ptys), dev_*() printk macros cannot be used. Define tty_*() printk macros that output in similar format to dev_*() macros (ie., <driver> <tty>: .....). Transform the most-trivial printk( LEVEL ...) usage to tty_*() usage. NB: The function name has been eliminated from messages with unique context, or prefixed to the format when given. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: core: Add helper fn to deref tty driver namePeter Hurley2015-12-131-0/+7
| | | | | | | | Similar to tty_name(), add tty_driver_name() helper to safely dereference tty->driver->name (otherwise return empty string). Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: core: Remove redundant oom messagePeter Hurley2015-12-131-3/+1
| | | | | | | | kmalloc() already emits a diagnostic for failed allocations; remove tty-specific message. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Make tty_paranoia_check() file scopePeter Hurley2015-12-131-1/+1
| | | | | | | | tty_paranoia_check() is only used within drivers/tty/tty_io.c; remove extern declaration in header and limit symbol to file scope. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Fix tty_send_xchar() lock order inversionPeter Hurley2015-11-201-0/+4
| | | | | | | | | | | The correct lock order is atomic_write_lock => termios_rwsem, as established by tty_write() => n_tty_write(). Fixes: c274f6ef1c666 ("tty: Hold termios_rwsem for tcflow(TCIxxx)") Reported-and-Tested-by: Dmitry Vyukov <dvyukov@google.com> Cc: <stable@vger.kernel.org> # v3.18+ Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Abstract tty buffer workPeter Hurley2015-10-171-1/+1
| | | | | | | | Introduce API functions to restart and cancel tty buffer work, rather than manipulate buffer work directly. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Prevent tty teardown during tty_write_message()Peter Hurley2015-10-171-4/+2
| | | | | | | | | | | | 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>
* tty: core: Use correct spinlock flavor in tiocspgrp()Peter Hurley2015-10-171-3/+2
| | | | | | | | | 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>
* tty: Combine SIGTTOU/SIGTTIN handlingPeter Hurley2015-10-171-22/+24
| | | | | | | | | | | | | | 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>
* drivers/tty: require read access for controlling terminalJann Horn2015-10-041-4/+27
| | | | | | | | | 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>
* tty: don't leak cdev in tty_cdev_add()Leon Yu2015-10-041-2/+7
| | | | | | | | | | | | | | | | Commit a3a10ce3429e ("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: a3a10ce3429e ("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>
* Avoid usb reset crashes by making tty_io cdevs truly dynamicRichard Watts2015-08-031-8/+16
| | | | | | | | Avoid usb reset crashes by making tty_io cdevs truly dynamic Signed-off-by: Richard Watts <rrw@kynesim.co.uk> Reported-by: Duncan Mackintosh <DMackintosh@cbnl.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: Replace #ifdef TTY_DEBUG_HANGUP with tty_debug_hangup()Peter Hurley2015-07-231-29/+18
| | | | | | | | Add tty_debug_hangup() macro which uses tty_debug to print the debug message; remove inlined #ifdefs. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tty: core: Add tty_debug() for printk(KERN_DEBUG) messagesPeter Hurley2015-07-231-24/+17
| | | | | | | | | | | 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>
* tty: core: Improve debug message contentPeter Hurley2015-07-231-13/+16
| | | | | | | | | 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>
* tty: add missing rcu_read_lock for task_pgrpPatrick Donnelly2015-07-231-5/+12
| | | | | | | | | | 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: remove buf parameter from tty_name()Rasmus Villemoes2015-05-061-17/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* tty: return tty->name directly from tty_nameRasmus Villemoes2015-05-061-5/+3
| | | | | | | | | | | 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>
* tty: constify return type of tty_nameRasmus Villemoes2015-05-061-1/+1
| | | | | | | | | | | | | | 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>
* tty: clean up the tty time logic a bitGreg Kroah-Hartman2015-03-261-2/+8
| | | | | | | | | | 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
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