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tty: Fix ldisc leak in failed tty_init_dev() 

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>
This commit is contained in:
Peter Hurley 2016-01-09 21:13:46 -08:00 committed by Greg Kroah-Hartman
parent f4f9edcf9b
commit c8b710b3e4
4 changed files with 8 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
drivers/tty/pty.c
View File

@ -408,7 +408,7 @@ static int pty_common_install(struct tty_driver *driver, struct tty_struct *tty,
the easy way .. */ the easy way .. */
retval = tty_init_termios(tty); retval = tty_init_termios(tty);
if (retval) if (retval)
goto err_deinit_tty; goto err_free_tty;
retval = tty_init_termios(o_tty); retval = tty_init_termios(o_tty);
if (retval) if (retval)
@ -447,8 +447,7 @@ static int pty_common_install(struct tty_driver *driver, struct tty_struct *tty,
err_free_termios: err_free_termios:
if (legacy) if (legacy)
tty_free_termios(tty); tty_free_termios(tty);
err_deinit_tty: err_free_tty:
deinitialize_tty_struct(o_tty);
free_tty_struct(o_tty); free_tty_struct(o_tty);
err_put_module: err_put_module:
module_put(driver->other->owner); module_put(driver->other->owner);

20
drivers/tty/tty_io.c
View File

@ -172,6 +172,7 @@ void free_tty_struct(struct tty_struct *tty)
{ {
if (!tty) if (!tty)
return; return;
tty_ldisc_deinit(tty);
put_device(tty->dev); put_device(tty->dev);
kfree(tty->write_buf); kfree(tty->write_buf);
tty->magic = 0xDEADDEAD; tty->magic = 0xDEADDEAD;
@ -1529,7 +1530,7 @@ struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
tty_lock(tty); tty_lock(tty);
retval = tty_driver_install_tty(driver, tty); retval = tty_driver_install_tty(driver, tty);
if (retval < 0) if (retval < 0)
goto err_deinit_tty; goto err_free_tty;
if (!tty->port) if (!tty->port)
tty->port = driver->ports[idx]; tty->port = driver->ports[idx];
@ -1551,9 +1552,8 @@ struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
/* Return the tty locked so that it cannot vanish under the caller */ /* Return the tty locked so that it cannot vanish under the caller */
return tty; return tty;
err_deinit_tty: err_free_tty:
tty_unlock(tty); tty_unlock(tty);
deinitialize_tty_struct(tty);
free_tty_struct(tty); free_tty_struct(tty);
err_module_put: err_module_put:
module_put(driver->owner); module_put(driver->owner);
@ -3162,20 +3162,6 @@ struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
return tty; return tty;
} }
/**
* deinitialize_tty_struct
* @tty: tty to deinitialize
*
* This subroutine deinitializes a tty structure that has been newly
* allocated but tty_release cannot be called on that yet.
*
* Locking: none - tty in question must not be exposed at this point
*/
void deinitialize_tty_struct(struct tty_struct *tty)
{
tty_ldisc_deinit(tty);
}
/** /**
* tty_put_char - write one character to a tty * tty_put_char - write one character to a tty
* @tty: tty * @tty: tty

5
drivers/tty/tty_ldisc.c
View File

@ -797,7 +797,7 @@ void tty_ldisc_init(struct tty_struct *tty)
} }
/** /**
* tty_ldisc_init - ldisc cleanup for new tty * tty_ldisc_deinit - ldisc cleanup for new tty
* @tty: tty that was allocated recently * @tty: tty that was allocated recently
* *
* The tty structure must not becompletely set up (tty_ldisc_setup) when * The tty structure must not becompletely set up (tty_ldisc_setup) when
@ -805,7 +805,8 @@ void tty_ldisc_init(struct tty_struct *tty)
*/ */
void tty_ldisc_deinit(struct tty_struct *tty) void tty_ldisc_deinit(struct tty_struct *tty)
{ {
tty_ldisc_put(tty->ldisc); if (tty->ldisc)
tty_ldisc_put(tty->ldisc);
tty->ldisc = NULL; tty->ldisc = NULL;
} }

1
include/linux/tty.h
View File

@ -509,7 +509,6 @@ extern int tty_alloc_file(struct file *file);
extern void tty_add_file(struct tty_struct *tty, struct file *file); extern void tty_add_file(struct tty_struct *tty, struct file *file);
extern void tty_free_file(struct file *file); extern void tty_free_file(struct file *file);
extern void free_tty_struct(struct tty_struct *tty); extern void free_tty_struct(struct tty_struct *tty);
extern void deinitialize_tty_struct(struct tty_struct *tty);
extern struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx); extern struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx);
extern int tty_release(struct inode *inode, struct file *filp); extern int tty_release(struct inode *inode, struct file *filp);
extern int tty_init_termios(struct tty_struct *tty); extern int tty_init_termios(struct tty_struct *tty);