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From: Peter Hurley <peter@hurleysoftware.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.cz>,
	linux-kernel@vger.kernel.org,
	Peter Hurley <peter@hurleysoftware.com>
Subject: [PATCH 01/12] tty: Fix ldisc leak in failed tty_init_dev()
Date: Fri, 27 Nov 2015 21:25:46 -0500	[thread overview]
Message-ID: <1448677557-16420-2-git-send-email-peter@hurleysoftware.com> (raw)
In-Reply-To: <1448677557-16420-1-git-send-email-peter@hurleysoftware.com>

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>
---
 drivers/tty/pty.c       |  5 ++---
 drivers/tty/tty_io.c    | 20 +++-----------------
 drivers/tty/tty_ldisc.c |  5 +++--
 include/linux/tty.h     |  1 -
 4 files changed, 8 insertions(+), 23 deletions(-)

diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
index b311004..8cbe802 100644
--- a/drivers/tty/pty.c
+++ b/drivers/tty/pty.c
@@ -408,7 +408,7 @@ static int pty_common_install(struct tty_driver *driver, struct tty_struct *tty,
 		   the easy way .. */
 		retval = tty_init_termios(tty);
 		if (retval)
-			goto err_deinit_tty;
+			goto err_free_tty;
 
 		retval = tty_init_termios(o_tty);
 		if (retval)
@@ -447,8 +447,7 @@ static int pty_common_install(struct tty_driver *driver, struct tty_struct *tty,
 err_free_termios:
 	if (legacy)
 		tty_free_termios(tty);
-err_deinit_tty:
-	deinitialize_tty_struct(o_tty);
+err_free_tty:
 	free_tty_struct(o_tty);
 err_put_module:
 	module_put(driver->other->owner);
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index eda8715..153b7b8 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -173,6 +173,7 @@ void free_tty_struct(struct tty_struct *tty)
 {
 	if (!tty)
 		return;
+	tty_ldisc_deinit(tty);
 	put_device(tty->dev);
 	kfree(tty->write_buf);
 	tty->magic = 0xDEADDEAD;
@@ -1535,7 +1536,7 @@ struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
 	tty_lock(tty);
 	retval = tty_driver_install_tty(driver, tty);
 	if (retval < 0)
-		goto err_deinit_tty;
+		goto err_free_tty;
 
 	if (!tty->port)
 		tty->port = driver->ports[idx];
@@ -1557,9 +1558,8 @@ 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 tty;
 
-err_deinit_tty:
+err_free_tty:
 	tty_unlock(tty);
-	deinitialize_tty_struct(tty);
 	free_tty_struct(tty);
 err_module_put:
 	module_put(driver->owner);
@@ -3169,20 +3169,6 @@ struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
 }
 
 /**
- *	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: tty
  *	@ch: character
diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c
index 3455908..9b3c11a 100644
--- a/drivers/tty/tty_ldisc.c
+++ b/drivers/tty/tty_ldisc.c
@@ -830,7 +830,7 @@ 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
  *
  *	The tty structure must not becompletely set up (tty_ldisc_setup) when
@@ -838,7 +838,8 @@ void tty_ldisc_init(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;
 }
 
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 8c8050d..9656c5d 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -510,7 +510,6 @@ extern int tty_alloc_file(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 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 int tty_release(struct inode *inode, struct file *filp);
 extern int tty_init_termios(struct tty_struct *tty);
-- 
2.6.3


  reply	other threads:[~2015-11-28  2:26 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-28  2:25 [PATCH 00/12] Rework tty_reopen() Peter Hurley
2015-11-28  2:25 ` Peter Hurley [this message]
2015-11-28  2:25 ` [PATCH 02/12] tty: Remove !tty check from free_tty_struct() Peter Hurley
2015-11-28  2:25 ` [PATCH 03/12] tty: Fix tty_init_termios() declaration Peter Hurley
2015-11-28  2:25 ` [PATCH 04/12] tty: Re-declare tty_driver_remove_tty() file scope Peter Hurley
2015-11-28  2:25 ` [PATCH 05/12] pty: Remove pty_unix98_shutdown() Peter Hurley
2015-11-28  2:25 ` [PATCH 06/12] tty: Remove __lockfunc annotation from tty lock functions Peter Hurley
2015-11-28  2:25 ` [PATCH 07/12] tty: Wait interruptibly for tty lock on reopen Peter Hurley
2015-11-28  2:25 ` [PATCH 08/12] pty: Prepare to redefine tty driver remove() interface Peter Hurley
2015-11-28  2:25 ` [PATCH 09/12] tty: Re-define " Peter Hurley
2015-11-28  2:25 ` [PATCH 10/12] tty: Consolidate noctty checks in tty_open() Peter Hurley
2015-11-28  2:25 ` [PATCH 11/12] tty: Refactor tty_open() Peter Hurley
2015-11-28  2:25 ` [PATCH 12/12] tty: Retry failed reopen if tty teardown in-progress Peter Hurley
2015-12-16 15:43 ` [PATCH 00/12] Rework tty_reopen() Peter Hurley
2015-12-17  5:53   ` Pratyush Anand
2015-12-17  7:15   ` Greg Kroah-Hartman
2016-01-10  5:13 ` [PATCH v2 00/10] " Peter Hurley
2016-01-10  5:13   ` [PATCH v2 01/10] tty: Wait interruptibly for tty lock on reopen Peter Hurley
2016-01-10  5:13   ` [PATCH v2 02/10] tty: Retry failed reopen if tty teardown in-progress Peter Hurley
2016-01-10  5:13   ` [PATCH v2 03/10] tty: Fix ldisc leak in failed tty_init_dev() Peter Hurley
2016-01-10  5:13   ` [PATCH v2 04/10] tty: Remove !tty check from free_tty_struct() Peter Hurley
2016-01-10  5:13   ` [PATCH v2 05/10] tty: Fix tty_init_termios() declaration Peter Hurley
2016-01-19  9:17     ` Johan Hovold
2016-01-10  5:13   ` [PATCH v2 06/10] tty: Re-declare tty_driver_remove_tty() file scope Peter Hurley
2016-01-10  5:13   ` [PATCH v2 07/10] pty: Remove pty_unix98_shutdown() Peter Hurley
2016-01-10  5:13   ` [PATCH v2 08/10] tty: Remove __lockfunc annotation from tty lock functions Peter Hurley
2016-01-10  5:13   ` [PATCH v2 09/10] tty: Consolidate noctty checks in tty_open() Peter Hurley
2016-03-26 17:58     ` Richard Weinberger
2016-03-26 19:06       ` Peter Hurley
2016-03-26 19:14         ` Richard Weinberger
2016-01-10  5:13   ` [PATCH v2 10/10] tty: Refactor tty_open() Peter Hurley

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