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-rw-r--r--drivers/tty/n_gsm.c7
-rw-r--r--drivers/tty/sysrq.c169
-rw-r--r--drivers/tty/tty_buffer.c14
-rw-r--r--drivers/tty/tty_io.c13
-rw-r--r--drivers/tty/tty_ldisc.c51
-rw-r--r--drivers/tty/vt/vc_screen.c6
6 files changed, 199 insertions, 61 deletions
diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index 11a25fa7d76b..44b8412a04e8 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -726,8 +726,8 @@ static void __gsm_data_queue(struct gsm_dlci *dlci, struct gsm_msg *msg)
if (msg->len < 128)
*--dp = (msg->len << 1) | EA;
else {
- *--dp = (msg->len >> 6) | EA;
- *--dp = (msg->len & 127) << 1;
+ *--dp = (msg->len >> 7); /* bits 7 - 15 */
+ *--dp = (msg->len & 127) << 1; /* bits 0 - 6 */
}
}
@@ -978,6 +978,8 @@ static void gsm_control_reply(struct gsm_mux *gsm, int cmd, u8 *data,
{
struct gsm_msg *msg;
msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype);
+ if (msg == NULL)
+ return;
msg->data[0] = (cmd & 0xFE) << 1 | EA; /* Clear C/R */
msg->data[1] = (dlen << 1) | EA;
memcpy(msg->data + 2, data, dlen);
@@ -2414,6 +2416,7 @@ static int gsmld_config(struct tty_struct *tty, struct gsm_mux *gsm,
gsm->mru = c->mru;
gsm->encoding = c->encapsulation;
gsm->adaption = c->adaption;
+ gsm->n2 = c->n2;
if (c->i == 1)
gsm->ftype = UIH;
diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
index eaa5d3efa79d..c556ed9db13d 100644
--- a/drivers/tty/sysrq.c
+++ b/drivers/tty/sysrq.c
@@ -554,7 +554,7 @@ EXPORT_SYMBOL(handle_sysrq);
#ifdef CONFIG_INPUT
/* Simple translation table for the SysRq keys */
-static const unsigned char sysrq_xlate[KEY_MAX + 1] =
+static const unsigned char sysrq_xlate[KEY_CNT] =
"\000\0331234567890-=\177\t" /* 0x00 - 0x0f */
"qwertyuiop[]\r\000as" /* 0x10 - 0x1f */
"dfghjkl;'`\000\\zxcv" /* 0x20 - 0x2f */
@@ -563,53 +563,129 @@ static const unsigned char sysrq_xlate[KEY_MAX + 1] =
"230\177\000\000\213\214\000\000\000\000\000\000\000\000\000\000" /* 0x50 - 0x5f */
"\r\000/"; /* 0x60 - 0x6f */
-static bool sysrq_down;
-static int sysrq_alt_use;
-static int sysrq_alt;
-static DEFINE_SPINLOCK(sysrq_event_lock);
+struct sysrq_state {
+ struct input_handle handle;
+ struct work_struct reinject_work;
+ unsigned long key_down[BITS_TO_LONGS(KEY_CNT)];
+ unsigned int alt;
+ unsigned int alt_use;
+ bool active;
+ bool need_reinject;
+};
+
+static void sysrq_reinject_alt_sysrq(struct work_struct *work)
+{
+ struct sysrq_state *sysrq =
+ container_of(work, struct sysrq_state, reinject_work);
+ struct input_handle *handle = &sysrq->handle;
+ unsigned int alt_code = sysrq->alt_use;
+
+ if (sysrq->need_reinject) {
+ /* Simulate press and release of Alt + SysRq */
+ input_inject_event(handle, EV_KEY, alt_code, 1);
+ input_inject_event(handle, EV_KEY, KEY_SYSRQ, 1);
+ input_inject_event(handle, EV_SYN, SYN_REPORT, 1);
+
+ input_inject_event(handle, EV_KEY, KEY_SYSRQ, 0);
+ input_inject_event(handle, EV_KEY, alt_code, 0);
+ input_inject_event(handle, EV_SYN, SYN_REPORT, 1);
+ }
+}
-static bool sysrq_filter(struct input_handle *handle, unsigned int type,
- unsigned int code, int value)
+static bool sysrq_filter(struct input_handle *handle,
+ unsigned int type, unsigned int code, int value)
{
+ struct sysrq_state *sysrq = handle->private;
+ bool was_active = sysrq->active;
bool suppress;
- /* We are called with interrupts disabled, just take the lock */
- spin_lock(&sysrq_event_lock);
+ switch (type) {
- if (type != EV_KEY)
- goto out;
+ case EV_SYN:
+ suppress = false;
+ break;
- switch (code) {
+ case EV_KEY:
+ switch (code) {
- case KEY_LEFTALT:
- case KEY_RIGHTALT:
- if (value)
- sysrq_alt = code;
- else {
- if (sysrq_down && code == sysrq_alt_use)
- sysrq_down = false;
+ case KEY_LEFTALT:
+ case KEY_RIGHTALT:
+ if (!value) {
+ /* One of ALTs is being released */
+ if (sysrq->active && code == sysrq->alt_use)
+ sysrq->active = false;
- sysrq_alt = 0;
+ sysrq->alt = KEY_RESERVED;
+
+ } else if (value != 2) {
+ sysrq->alt = code;
+ sysrq->need_reinject = false;
+ }
+ break;
+
+ case KEY_SYSRQ:
+ if (value == 1 && sysrq->alt != KEY_RESERVED) {
+ sysrq->active = true;
+ sysrq->alt_use = sysrq->alt;
+ /*
+ * If nothing else will be pressed we'll need
+ * to * re-inject Alt-SysRq keysroke.
+ */
+ sysrq->need_reinject = true;
+ }
+
+ /*
+ * Pretend that sysrq was never pressed at all. This
+ * is needed to properly handle KGDB which will try
+ * to release all keys after exiting debugger. If we
+ * do not clear key bit it KGDB will end up sending
+ * release events for Alt and SysRq, potentially
+ * triggering print screen function.
+ */
+ if (sysrq->active)
+ clear_bit(KEY_SYSRQ, handle->dev->key);
+
+ break;
+
+ default:
+ if (sysrq->active && value && value != 2) {
+ sysrq->need_reinject = false;
+ __handle_sysrq(sysrq_xlate[code], true);
+ }
+ break;
}
- break;
- case KEY_SYSRQ:
- if (value == 1 && sysrq_alt) {
- sysrq_down = true;
- sysrq_alt_use = sysrq_alt;
+ suppress = sysrq->active;
+
+ if (!sysrq->active) {
+ /*
+ * If we are not suppressing key presses keep track of
+ * keyboard state so we can release keys that have been
+ * pressed before entering SysRq mode.
+ */
+ if (value)
+ set_bit(code, sysrq->key_down);
+ else
+ clear_bit(code, sysrq->key_down);
+
+ if (was_active)
+ schedule_work(&sysrq->reinject_work);
+
+ } else if (value == 0 &&
+ test_and_clear_bit(code, sysrq->key_down)) {
+ /*
+ * Pass on release events for keys that was pressed before
+ * entering SysRq mode.
+ */
+ suppress = false;
}
break;
default:
- if (sysrq_down && value && value != 2)
- __handle_sysrq(sysrq_xlate[code], true);
+ suppress = sysrq->active;
break;
}
-out:
- suppress = sysrq_down;
- spin_unlock(&sysrq_event_lock);
-
return suppress;
}
@@ -617,28 +693,28 @@ static int sysrq_connect(struct input_handler *handler,
struct input_dev *dev,
const struct input_device_id *id)
{
- struct input_handle *handle;
+ struct sysrq_state *sysrq;
int error;
- sysrq_down = false;
- sysrq_alt = 0;
-
- handle = kzalloc(sizeof(struct input_handle), GFP_KERNEL);
- if (!handle)
+ sysrq = kzalloc(sizeof(struct sysrq_state), GFP_KERNEL);
+ if (!sysrq)
return -ENOMEM;
- handle->dev = dev;
- handle->handler = handler;
- handle->name = "sysrq";
+ INIT_WORK(&sysrq->reinject_work, sysrq_reinject_alt_sysrq);
+
+ sysrq->handle.dev = dev;
+ sysrq->handle.handler = handler;
+ sysrq->handle.name = "sysrq";
+ sysrq->handle.private = sysrq;
- error = input_register_handle(handle);
+ error = input_register_handle(&sysrq->handle);
if (error) {
pr_err("Failed to register input sysrq handler, error %d\n",
error);
goto err_free;
}
- error = input_open_device(handle);
+ error = input_open_device(&sysrq->handle);
if (error) {
pr_err("Failed to open input device, error %d\n", error);
goto err_unregister;
@@ -647,17 +723,20 @@ static int sysrq_connect(struct input_handler *handler,
return 0;
err_unregister:
- input_unregister_handle(handle);
+ input_unregister_handle(&sysrq->handle);
err_free:
- kfree(handle);
+ kfree(sysrq);
return error;
}
static void sysrq_disconnect(struct input_handle *handle)
{
+ struct sysrq_state *sysrq = handle->private;
+
input_close_device(handle);
+ cancel_work_sync(&sysrq->reinject_work);
input_unregister_handle(handle);
- kfree(handle);
+ kfree(sysrq);
}
/*
diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index cc1e9850d655..d8210ca00720 100644
--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -413,7 +413,8 @@ static void flush_to_ldisc(struct work_struct *work)
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_struct *work)
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_struct *work)
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/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index d2333ab23d07..464d09d97873 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -559,6 +559,9 @@ void __tty_hangup(struct tty_struct *tty)
tty_lock();
+ /* some functions below drop BTM, so we need this bit */
+ set_bit(TTY_HUPPING, &tty->flags);
+
/* inuse_filps is protected by the single tty lock,
this really needs to change if we want to flush the
workqueue with the lock held */
@@ -578,6 +581,10 @@ void __tty_hangup(struct tty_struct *tty)
}
spin_unlock(&tty_files_lock);
+ /*
+ * it drops BTM and thus races with reopen
+ * we protect the race by TTY_HUPPING
+ */
tty_ldisc_hangup(tty);
read_lock(&tasklist_lock);
@@ -615,7 +622,6 @@ void __tty_hangup(struct tty_struct *tty)
tty->session = NULL;
tty->pgrp = NULL;
tty->ctrl_status = 0;
- set_bit(TTY_HUPPED, &tty->flags);
spin_unlock_irqrestore(&tty->ctrl_lock, flags);
/* Account for the p->signal references we killed */
@@ -641,6 +647,7 @@ void __tty_hangup(struct tty_struct *tty)
* can't yet guarantee all that.
*/
set_bit(TTY_HUPPED, &tty->flags);
+ clear_bit(TTY_HUPPING, &tty->flags);
tty_ldisc_enable(tty);
tty_unlock();
@@ -1310,7 +1317,9 @@ static int tty_reopen(struct tty_struct *tty)
{
struct tty_driver *driver = tty->driver;
- if (test_bit(TTY_CLOSING, &tty->flags))
+ if (test_bit(TTY_CLOSING, &tty->flags) ||
+ test_bit(TTY_HUPPING, &tty->flags) ||
+ test_bit(TTY_LDISC_CHANGING, &tty->flags))
return -EIO;
if (driver->type == TTY_DRIVER_TYPE_PTY &&
diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c
index 412f9775d19c..4214d58276f7 100644
--- a/drivers/tty/tty_ldisc.c
+++ b/drivers/tty/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 *ld)
return;
}
local_irq_restore(flags);
+ wake_up(&tty_ldisc_idle);
}
/**
@@ -452,6 +454,8 @@ static int tty_ldisc_open(struct tty_struct *tty, struct tty_ldisc *ld)
/* BTM here locks versus a hangup event */
WARN_ON(!tty_locked());
ret = ld->ops->open(tty);
+ if (ret)
+ clear_bit(TTY_LDISC_OPEN, &tty->flags);
return ret;
}
return 0;
@@ -531,6 +535,23 @@ static int tty_ldisc_halt(struct tty_struct *tty)
}
/**
+ * 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 +655,17 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc)
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 +699,7 @@ int tty_set_ldisc(struct tty_struct *tty, int ldisc)
tty_ldisc_put(o_ldisc);
+enable:
/*
* Allow ldisc referencing to occur again
*/
@@ -714,9 +745,12 @@ static void tty_reset_termios(struct tty_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);
@@ -724,10 +758,10 @@ static void tty_ldisc_reinit(struct tty_struct *tty, int ldisc)
/*
* 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;
}
/**
@@ -802,13 +836,16 @@ void tty_ldisc_hangup(struct tty_struct *tty)
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);
diff --git a/drivers/tty/vt/vc_screen.c b/drivers/tty/vt/vc_screen.c
index 273ab44cc91d..eab3a1ff99e4 100644
--- a/drivers/tty/vt/vc_screen.c
+++ b/drivers/tty/vt/vc_screen.c
@@ -553,12 +553,12 @@ static unsigned int
vcs_poll(struct file *file, poll_table *wait)
{
struct vcs_poll_data *poll = vcs_poll_data_get(file);
- int ret = 0;
+ int ret = DEFAULT_POLLMASK|POLLERR|POLLPRI;
if (poll) {
poll_wait(file, &poll->waitq, wait);
- if (!poll->seen_last_update)
- ret = POLLIN | POLLRDNORM;
+ if (poll->seen_last_update)
+ ret = DEFAULT_POLLMASK;
}
return ret;
}