]> git.ipfire.org Git - thirdparty/kernel/stable-queue.git/commitdiff
.36 patches
authorGreg Kroah-Hartman <gregkh@suse.de>
Sat, 4 Dec 2010 00:00:17 +0000 (16:00 -0800)
committerGreg Kroah-Hartman <gregkh@suse.de>
Sat, 4 Dec 2010 00:00:17 +0000 (16:00 -0800)
queue-2.6.36/intel-gtt-fix-gtt_total_entries-detection.patch [deleted file]
queue-2.6.36/series
queue-2.6.36/sgi-xp-incoming-xpc-channel-messages-can-come-in-after-the-channel-s-partition-structures-have-been-torn-down.patch [deleted file]
queue-2.6.36/tty-prevent-dos-in-the-flush_to_ldisc.patch [new file with mode: 0644]
queue-2.6.36/tty-restore-tty_ldisc_wait_idle.patch [new file with mode: 0644]
queue-2.6.36/tty_ldisc-fix-bug-on-hangup.patch [new file with mode: 0644]

diff --git a/queue-2.6.36/intel-gtt-fix-gtt_total_entries-detection.patch b/queue-2.6.36/intel-gtt-fix-gtt_total_entries-detection.patch
deleted file mode 100644 (file)
index b088d90..0000000
+++ /dev/null
@@ -1,128 +0,0 @@
-From e5e408fc94595aab897f613b6f4e2f5b36870a6f Mon Sep 17 00:00:00 2001
-From: Daniel Vetter <daniel.vetter@ffwll.ch>
-Date: Sat, 28 Aug 2010 11:04:32 +0200
-Subject: intel-gtt: fix gtt_total_entries detection
-
-From: Daniel Vetter <daniel.vetter@ffwll.ch>
-
-commit e5e408fc94595aab897f613b6f4e2f5b36870a6f upstream.
-
-In commit f1befe71 Chris Wilson added some code to clear the full gtt
-on g33/pineview instead of just the mappable part. The code looks like
-it was copy-pasted from agp/intel-gtt.c, at least an identical piece
-of code is still there (in intel_i830_init_gtt_entries). This lead to
-a regression in 2.6.35 which was supposedly fixed in commit e7b96f28
-
-Now this commit makes absolutely no sense to me. It seems to be
-slightly confused about chipset generations - it references docs for
-4th gen but the regression concerns 3rd gen g33. Luckily the the g33
-gmch docs are available with the GMCH Graphics Control pci config
-register definitions. The other (bigger problem) is that the new
-check in there uses the i830 stolen mem bits (.5M, 1M or 8M of stolen
-mem). They are different since the i855GM.
-
-The most likely case is that it hits the 512M fallback, which was
-probably the right thing for the boxes this was tested on.
-
-So the original approach by Chris Wilson seems to be wrong and the
-current code is definitely wrong. There is a third approach by Jesse
-Barnes from his RFC patch "Who wants a bigger GTT mapping range?"
-where he simply shoves g33 in the same clause like later chipset
-generations.
-
-I've asked him and Jesse confirmed that this should work. So implement
-it.
-
-Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=16891$
-Tested-by: Anisse Astier <anisse@astier.eu>
-Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
-Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
-Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-
-diff --git a/drivers/char/agp/intel-gtt.c b/drivers/char/agp/intel-gtt.c
-index 56bcf27..3b84d84 100644
---- a/drivers/char/agp/intel-gtt.c
-+++ b/drivers/char/agp/intel-gtt.c
-@@ -699,71 +699,43 @@ static unsigned int intel_gtt_stolen_entries(void)
- static unsigned int intel_gtt_total_entries(void)
- {
-       int size;
--      u16 gmch_ctrl;
--      if (IS_I965) {
-+      if (IS_G33 || IS_I965 || IS_G4X) {
-               u32 pgetbl_ctl;
-               pgetbl_ctl = readl(intel_private.registers+I810_PGETBL_CTL);
--              /* The 965 has a field telling us the size of the GTT,
--               * which may be larger than what is necessary to map the
--               * aperture.
--               */
-               switch (pgetbl_ctl & I965_PGETBL_SIZE_MASK) {
-               case I965_PGETBL_SIZE_128KB:
--                      size = 128;
-+                      size = KB(128);
-                       break;
-               case I965_PGETBL_SIZE_256KB:
--                      size = 256;
-+                      size = KB(256);
-                       break;
-               case I965_PGETBL_SIZE_512KB:
--                      size = 512;
-+                      size = KB(512);
-                       break;
-               case I965_PGETBL_SIZE_1MB:
--                      size = 1024;
-+                      size = KB(1024);
-                       break;
-               case I965_PGETBL_SIZE_2MB:
--                      size = 2048;
-+                      size = KB(2048);
-                       break;
-               case I965_PGETBL_SIZE_1_5MB:
--                      size = 1024 + 512;
-+                      size = KB(1024 + 512);
-                       break;
-               default:
-                       dev_info(&intel_private.pcidev->dev,
-                                "unknown page table size, assuming 512KB\n");
--                      size = 512;
--              }
--              size += 4; /* add in BIOS popup space */
--      } else if (IS_G33 && !IS_PINEVIEW) {
--      /* G33's GTT size defined in gmch_ctrl */
--              switch (gmch_ctrl & G33_PGETBL_SIZE_MASK) {
--              case G33_PGETBL_SIZE_1M:
--                      size = 1024;
--                      break;
--              case G33_PGETBL_SIZE_2M:
--                      size = 2048;
--                      break;
--              default:
--                      dev_info(&intel_private.bridge_dev->dev,
--                               "unknown page table size 0x%x, assuming 512KB\n",
--                              (gmch_ctrl & G33_PGETBL_SIZE_MASK));
--                      size = 512;
-+                      size = KB(512);
-               }
--              size += 4;
--      } else if (IS_G4X || IS_PINEVIEW) {
--              /* On 4 series hardware, GTT stolen is separate from graphics
--               * stolen, ignore it in stolen gtt entries counting.  However,
--               * 4KB of the stolen memory doesn't get mapped to the GTT.
--               */
--              size = 4;
-+
-+              return size/4;
-       } else {
-               /* On previous hardware, the GTT size was just what was
-                * required to map the aperture.
-                */
--              size = agp_bridge->driver->fetch_size() + 4;
-+              return intel_private.base.gtt_mappable_entries;
-       }
--
--      return size/KB(4);
- }
- #endif
index cf20172a751a964fdfe1054b3cffea01e136d114..fcc39826cd4daa7c569716daac60f4adf42a64f8 100644 (file)
@@ -134,5 +134,6 @@ md-fix-regression-with-raid1-arrays-without-persistent-metadata.patch
 md-raid1-really-fix-recovery-looping-when-single-good-device-fails.patch
 md-fix-return-value-of-rdev_size_change.patch
 alsa-hda-use-bios-auto-parsing-instead-of-existing-model-quirk-for-medion-md2.patch
-intel-gtt-fix-gtt_total_entries-detection.patch
-sgi-xp-incoming-xpc-channel-messages-can-come-in-after-the-channel-s-partition-structures-have-been-torn-down.patch
+tty-prevent-dos-in-the-flush_to_ldisc.patch
+tty-restore-tty_ldisc_wait_idle.patch
+tty_ldisc-fix-bug-on-hangup.patch
diff --git a/queue-2.6.36/sgi-xp-incoming-xpc-channel-messages-can-come-in-after-the-channel-s-partition-structures-have-been-torn-down.patch b/queue-2.6.36/sgi-xp-incoming-xpc-channel-messages-can-come-in-after-the-channel-s-partition-structures-have-been-torn-down.patch
deleted file mode 100644 (file)
index a81e5d1..0000000
+++ /dev/null
@@ -1,93 +0,0 @@
-From 09358972bff5ce99de496bbba97c85d417b3c054 Mon Sep 17 00:00:00 2001
-From: Robin Holt <holt@sgi.com>
-Date: Tue, 26 Oct 2010 14:21:15 -0700
-Subject: sgi-xp: incoming XPC channel messages can come in after the channel's partition structures have been torn down
-
-From: Robin Holt <holt@sgi.com>
-
-commit 09358972bff5ce99de496bbba97c85d417b3c054 upstream.
-
-Under some workloads, some channel messages have been observed being
-delayed on the sending side past the point where the receiving side has
-been able to tear down its partition structures.
-
-This condition is already detected in xpc_handle_activate_IRQ_uv(), but
-that information is not given to xpc_handle_activate_mq_msg_uv().  As a
-result, xpc_handle_activate_mq_msg_uv() assumes the structures still exist
-and references them, causing a NULL-pointer deref.
-
-Signed-off-by: Robin Holt <holt@sgi.com>
-Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-
-diff --git a/drivers/misc/sgi-xp/xpc_uv.c b/drivers/misc/sgi-xp/xpc_uv.c
-index 1f59ee2..17bbacb 100644
---- a/drivers/misc/sgi-xp/xpc_uv.c
-+++ b/drivers/misc/sgi-xp/xpc_uv.c
-@@ -417,6 +417,7 @@ xpc_process_activate_IRQ_rcvd_uv(void)
- static void
- xpc_handle_activate_mq_msg_uv(struct xpc_partition *part,
-                             struct xpc_activate_mq_msghdr_uv *msg_hdr,
-+                            int part_setup,
-                             int *wakeup_hb_checker)
- {
-       unsigned long irq_flags;
-@@ -481,6 +482,9 @@ xpc_handle_activate_mq_msg_uv(struct xpc_partition *part,
-       case XPC_ACTIVATE_MQ_MSG_CHCTL_CLOSEREQUEST_UV: {
-               struct xpc_activate_mq_msg_chctl_closerequest_uv *msg;
-+              if (!part_setup)
-+                      break;
-+
-               msg = container_of(msg_hdr, struct
-                                  xpc_activate_mq_msg_chctl_closerequest_uv,
-                                  hdr);
-@@ -497,6 +501,9 @@ xpc_handle_activate_mq_msg_uv(struct xpc_partition *part,
-       case XPC_ACTIVATE_MQ_MSG_CHCTL_CLOSEREPLY_UV: {
-               struct xpc_activate_mq_msg_chctl_closereply_uv *msg;
-+              if (!part_setup)
-+                      break;
-+
-               msg = container_of(msg_hdr, struct
-                                  xpc_activate_mq_msg_chctl_closereply_uv,
-                                  hdr);
-@@ -511,6 +518,9 @@ xpc_handle_activate_mq_msg_uv(struct xpc_partition *part,
-       case XPC_ACTIVATE_MQ_MSG_CHCTL_OPENREQUEST_UV: {
-               struct xpc_activate_mq_msg_chctl_openrequest_uv *msg;
-+              if (!part_setup)
-+                      break;
-+
-               msg = container_of(msg_hdr, struct
-                                  xpc_activate_mq_msg_chctl_openrequest_uv,
-                                  hdr);
-@@ -528,6 +538,9 @@ xpc_handle_activate_mq_msg_uv(struct xpc_partition *part,
-       case XPC_ACTIVATE_MQ_MSG_CHCTL_OPENREPLY_UV: {
-               struct xpc_activate_mq_msg_chctl_openreply_uv *msg;
-+              if (!part_setup)
-+                      break;
-+
-               msg = container_of(msg_hdr, struct
-                                  xpc_activate_mq_msg_chctl_openreply_uv, hdr);
-               args = &part->remote_openclose_args[msg->ch_number];
-@@ -545,6 +558,9 @@ xpc_handle_activate_mq_msg_uv(struct xpc_partition *part,
-       case XPC_ACTIVATE_MQ_MSG_CHCTL_OPENCOMPLETE_UV: {
-               struct xpc_activate_mq_msg_chctl_opencomplete_uv *msg;
-+              if (!part_setup)
-+                      break;
-+
-               msg = container_of(msg_hdr, struct
-                               xpc_activate_mq_msg_chctl_opencomplete_uv, hdr);
-               spin_lock_irqsave(&part->chctl_lock, irq_flags);
-@@ -621,6 +637,7 @@ xpc_handle_activate_IRQ_uv(int irq, void *dev_id)
-                       part_referenced = xpc_part_ref(part);
-                       xpc_handle_activate_mq_msg_uv(part, msg_hdr,
-+                                                    part_referenced,
-                                                     &wakeup_hb_checker);
-                       if (part_referenced)
-                               xpc_part_deref(part);
diff --git a/queue-2.6.36/tty-prevent-dos-in-the-flush_to_ldisc.patch b/queue-2.6.36/tty-prevent-dos-in-the-flush_to_ldisc.patch
new file mode 100644 (file)
index 0000000..a05acb0
--- /dev/null
@@ -0,0 +1,107 @@
+From e045fec48970df84647a47930fcf7a22ff7229c0 Mon Sep 17 00:00:00 2001
+From: Jiri Olsa <jolsa@redhat.com>
+Date: Mon, 8 Nov 2010 19:01:47 +0100
+Subject: tty: prevent DOS in the flush_to_ldisc
+
+From: Jiri Olsa <jolsa@redhat.com>
+
+commit e045fec48970df84647a47930fcf7a22ff7229c0 upstream.
+
+There's a small window inside the flush_to_ldisc function,
+where the tty is unlocked and calling ldisc's receive_buf
+function. If in this window new buffer is added to the tty,
+the processing might never leave the flush_to_ldisc function.
+
+This scenario will hog the cpu, causing other tty processing
+starving, and making it impossible to interface the computer
+via tty.
+
+I was able to exploit this via pty interface by sending only
+control characters to the master input, causing the flush_to_ldisc
+to be scheduled, but never actually generate any output.
+
+To reproduce, please run multiple instances of following code.
+
+- SNIP
+#define _XOPEN_SOURCE
+#include <stdlib.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+int main(int argc, char **argv)
+{
+        int i, slave, master = getpt();
+        char buf[8192];
+
+        sprintf(buf, "%s", ptsname(master));
+        grantpt(master);
+        unlockpt(master);
+
+        slave = open(buf, O_RDWR);
+        if (slave < 0) {
+                perror("open slave failed");
+                return 1;
+        }
+
+        for(i = 0; i < sizeof(buf); i++)
+                buf[i] = rand() % 32;
+
+        while(1) {
+                write(master, buf, sizeof(buf));
+        }
+
+        return 0;
+}
+- SNIP
+
+The attached patch (based on -next tree) fixes this by checking on the
+tty buffer tail. Once it's reached, the current work is rescheduled
+and another could run.
+
+Signed-off-by: Jiri Olsa <jolsa@redhat.com>
+Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
+Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
+
+---
+ drivers/char/tty_buffer.c |   14 ++++++++++++--
+ 1 file changed, 12 insertions(+), 2 deletions(-)
+
+--- a/drivers/char/tty_buffer.c
++++ b/drivers/char/tty_buffer.c
+@@ -413,7 +413,8 @@ static void flush_to_ldisc(struct work_s
+       spin_lock_irqsave(&tty->buf.lock, flags);
+       if (!test_and_set_bit(TTY_FLUSHING, &tty->flags)) {
+-              struct tty_buffer *head;
++              struct tty_buffer *head, *tail = tty->buf.tail;
++              int seen_tail = 0;
+               while ((head = tty->buf.head) != NULL) {
+                       int count;
+                       char *char_buf;
+@@ -423,6 +424,15 @@ static void flush_to_ldisc(struct work_s
+                       if (!count) {
+                               if (head->next == NULL)
+                                       break;
++                              /*
++                                There's a possibility tty might get new buffer
++                                added during the unlock window below. We could
++                                end up spinning in here forever hogging the CPU
++                                completely. To avoid this let's have a rest each
++                                time we processed the tail buffer.
++                              */
++                              if (tail == head)
++                                      seen_tail = 1;
+                               tty->buf.head = head->next;
+                               tty_buffer_free(tty, head);
+                               continue;
+@@ -432,7 +442,7 @@ static void flush_to_ldisc(struct work_s
+                          line discipline as we want to empty the queue */
+                       if (test_bit(TTY_FLUSHPENDING, &tty->flags))
+                               break;
+-                      if (!tty->receive_room) {
++                      if (!tty->receive_room || seen_tail) {
+                               schedule_delayed_work(&tty->buf.work, 1);
+                               break;
+                       }
diff --git a/queue-2.6.36/tty-restore-tty_ldisc_wait_idle.patch b/queue-2.6.36/tty-restore-tty_ldisc_wait_idle.patch
new file mode 100644 (file)
index 0000000..164d4f8
--- /dev/null
@@ -0,0 +1,116 @@
+From 100eeae2c5ce23b4db93ff320ee330ef1d740151 Mon Sep 17 00:00:00 2001
+From: Jiri Slaby <jslaby@suse.cz>
+Date: Sun, 31 Oct 2010 23:17:51 +0100
+Subject: TTY: restore tty_ldisc_wait_idle
+
+From: Jiri Slaby <jslaby@suse.cz>
+
+commit 100eeae2c5ce23b4db93ff320ee330ef1d740151 upstream.
+
+It was removed in 65b770468e98 (tty-ldisc: turn ldisc user count into
+a proper refcount), but we need to wait for last user to quit the
+ldisc before we close it in tty_set_ldisc.
+
+Otherwise weird things start to happen. There might be processes
+waiting in tty_read->n_tty_read on tty->read_wait for input to appear
+and at that moment, a change of ldisc is fatal. n_tty_close is called,
+it frees read_buf and the waiting process is still in the middle of
+reading and goes nuts after it is woken.
+
+Previously we prevented close to happen when others are in ldisc ops
+by tty_ldisc_wait_idle in tty_set_ldisc. But the commit above removed
+that. So revoke the change and test whether there is 1 user (=we), and
+allow the close then.
+
+We can do that without ldisc/tty locks, because nobody else can open
+the device due to TTY_LDISC_CHANGING bit set, so we in fact wait for
+everybody to leave.
+
+I don't understand why tty_ldisc_lock would be needed either when the
+counter is an atomic variable, so this is a lockless
+tty_ldisc_wait_idle.
+
+On the other hand, if we fail to wait (timeout or signal), we have to
+reenable the halted ldiscs, so we take ldisc lock and reuse the setup
+path at the end of tty_set_ldisc.
+
+Signed-off-by: Jiri Slaby <jslaby@suse.cz>
+Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
+Tested-by: Sebastian Andrzej Siewior <bigeasy@breakpoint.cc>
+LKML-Reference: <20101031104136.GA511@Chamillionaire.breakpoint.cc>
+LKML-Reference: <1287669539-22644-1-git-send-email-jslaby@suse.cz>
+Cc: Alan Cox <alan@linux.intel.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
+
+---
+ drivers/char/tty_ldisc.c |   29 +++++++++++++++++++++++++++++
+ 1 file changed, 29 insertions(+)
+
+--- a/drivers/char/tty_ldisc.c
++++ b/drivers/char/tty_ldisc.c
+@@ -47,6 +47,7 @@
+ static DEFINE_SPINLOCK(tty_ldisc_lock);
+ static DECLARE_WAIT_QUEUE_HEAD(tty_ldisc_wait);
++static DECLARE_WAIT_QUEUE_HEAD(tty_ldisc_idle);
+ /* Line disc dispatch table */
+ static struct tty_ldisc_ops *tty_ldiscs[NR_LDISCS];
+@@ -83,6 +84,7 @@ static void put_ldisc(struct tty_ldisc *
+               return;
+       }
+       local_irq_restore(flags);
++      wake_up(&tty_ldisc_idle);
+ }
+ /**
+@@ -531,6 +533,23 @@ static int tty_ldisc_halt(struct tty_str
+ }
+ /**
++ *    tty_ldisc_wait_idle     -       wait for the ldisc to become idle
++ *    @tty: tty to wait for
++ *
++ *    Wait for the line discipline to become idle. The discipline must
++ *    have been halted for this to guarantee it remains idle.
++ */
++static int tty_ldisc_wait_idle(struct tty_struct *tty)
++{
++      int ret;
++      ret = wait_event_interruptible_timeout(tty_ldisc_idle,
++                      atomic_read(&tty->ldisc->users) == 1, 5 * HZ);
++      if (ret < 0)
++              return ret;
++      return ret > 0 ? 0 : -EBUSY;
++}
++
++/**
+  *    tty_set_ldisc           -       set line discipline
+  *    @tty: the terminal to set
+  *    @ldisc: the line discipline
+@@ -634,8 +653,17 @@ int tty_set_ldisc(struct tty_struct *tty
+       flush_scheduled_work();
++      retval = tty_ldisc_wait_idle(tty);
++
+       tty_lock();
+       mutex_lock(&tty->ldisc_mutex);
++
++      /* handle wait idle failure locked */
++      if (retval) {
++              tty_ldisc_put(new_ldisc);
++              goto enable;
++      }
++
+       if (test_bit(TTY_HUPPED, &tty->flags)) {
+               /* We were raced by the hangup method. It will have stomped
+                  the ldisc data and closed the ldisc down */
+@@ -669,6 +697,7 @@ int tty_set_ldisc(struct tty_struct *tty
+       tty_ldisc_put(o_ldisc);
++enable:
+       /*
+        *      Allow ldisc referencing to occur again
+        */
diff --git a/queue-2.6.36/tty_ldisc-fix-bug-on-hangup.patch b/queue-2.6.36/tty_ldisc-fix-bug-on-hangup.patch
new file mode 100644 (file)
index 0000000..9f6f411
--- /dev/null
@@ -0,0 +1,74 @@
+From 1c95ba1e1de7edffc0c4e275e147f1a9eb1f81ae Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Philippe=20R=C3=A9tornaz?= <philippe.retornaz@epfl.ch>
+Date: Wed, 27 Oct 2010 17:13:21 +0200
+Subject: tty_ldisc: Fix BUG() on hangup
+
+From: =?UTF-8?q?Philippe=20R=C3=A9tornaz?= <philippe.retornaz@epfl.ch>
+
+commit 1c95ba1e1de7edffc0c4e275e147f1a9eb1f81ae upstream.
+
+A kernel BUG when bluetooth rfcomm connection drop while the associated
+serial port is open is sometime triggered.
+
+It seems that the line discipline can disappear between the
+tty_ldisc_put and tty_ldisc_get. This patch fall back to the N_TTY line
+discipline if the previous discipline is not available anymore.
+
+Signed-off-by: Philippe Retornaz <philippe.retornaz@epfl.ch>
+Acked-by: Alan Cox <alan@linux.intel.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
+
+---
+ drivers/char/tty_ldisc.c |   20 +++++++++++++-------
+ 1 file changed, 13 insertions(+), 7 deletions(-)
+
+--- a/drivers/char/tty_ldisc.c
++++ b/drivers/char/tty_ldisc.c
+@@ -743,9 +743,12 @@ static void tty_reset_termios(struct tty
+  *    state closed
+  */
+-static void tty_ldisc_reinit(struct tty_struct *tty, int ldisc)
++static int tty_ldisc_reinit(struct tty_struct *tty, int ldisc)
+ {
+-      struct tty_ldisc *ld;
++      struct tty_ldisc *ld = tty_ldisc_get(ldisc);
++
++      if (IS_ERR(ld))
++              return -1;
+       tty_ldisc_close(tty, tty->ldisc);
+       tty_ldisc_put(tty->ldisc);
+@@ -753,10 +756,10 @@ static void tty_ldisc_reinit(struct tty_
+       /*
+        *      Switch the line discipline back
+        */
+-      ld = tty_ldisc_get(ldisc);
+-      BUG_ON(IS_ERR(ld));
+       tty_ldisc_assign(tty, ld);
+       tty_set_termios_ldisc(tty, ldisc);
++
++      return 0;
+ }
+ /**
+@@ -831,13 +834,16 @@ void tty_ldisc_hangup(struct tty_struct
+          a FIXME */
+       if (tty->ldisc) {       /* Not yet closed */
+               if (reset == 0) {
+-                      tty_ldisc_reinit(tty, tty->termios->c_line);
+-                      err = tty_ldisc_open(tty, tty->ldisc);
++
++                      if (!tty_ldisc_reinit(tty, tty->termios->c_line))
++                              err = tty_ldisc_open(tty, tty->ldisc);
++                      else
++                              err = 1;
+               }
+               /* If the re-open fails or we reset then go to N_TTY. The
+                  N_TTY open cannot fail */
+               if (reset || err) {
+-                      tty_ldisc_reinit(tty, N_TTY);
++                      BUG_ON(tty_ldisc_reinit(tty, N_TTY));
+                       WARN_ON(tty_ldisc_open(tty, tty->ldisc));
+               }
+               tty_ldisc_enable(tty);