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Subject[PATCH 1/7] tty: core: Improve debug message content
Date
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>
---
drivers/tty/tty_io.c | 29 ++++++++++++++++-------------
1 file changed, 16 insertions(+), 13 deletions(-)

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 57fc6ee..2d9811a 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -524,7 +524,8 @@ static void __proc_set_tty(struct tty_struct *tty)
spin_unlock_irqrestore(&tty->ctrl_lock, flags);
tty->session = get_pid(task_session(current));
if (current->signal->tty) {
- printk(KERN_DEBUG "tty not NULL!!\n");
+ printk(KERN_DEBUG "%s: %s: current tty %s not NULL!!\n",
+ __func__, tty->name, current->signal->tty->name);
tty_kref_put(current->signal->tty);
}
put_pid(current->signal->tty_old_pgrp);
@@ -922,8 +923,7 @@ void disassociate_ctty(int on_exit)
tty_kref_put(tty);
} else {
#ifdef TTY_DEBUG_HANGUP
- printk(KERN_DEBUG "error attempted to write to tty [0x%p]"
- " = NULL", tty);
+ printk(KERN_DEBUG "%s: no current tty\n", __func__);
#endif
}

@@ -1705,8 +1705,8 @@ static int tty_release_checks(struct tty_struct *tty, int idx)
{
#ifdef TTY_PARANOIA_CHECK
if (idx < 0 || idx >= tty->driver->num) {
- printk(KERN_DEBUG "%s: bad idx when trying to free (%s)\n",
- __func__, tty->name);
+ printk(KERN_DEBUG "%s: %s: bad idx %d\n",
+ __func__, tty->name, idx);
return -1;
}

@@ -1715,20 +1715,22 @@ static int tty_release_checks(struct tty_struct *tty, int idx)
return 0;

if (tty != tty->driver->ttys[idx]) {
- printk(KERN_DEBUG "%s: driver.table[%d] not tty for (%s)\n",
- __func__, idx, tty->name);
+ printk(KERN_DEBUG "%s: %s: bad driver table[%d] = %p\n",
+ __func__, tty->name, idx, tty->driver->ttys[idx]);
return -1;
}
if (tty->driver->other) {
struct tty_struct *o_tty = tty->link;

if (o_tty != tty->driver->other->ttys[idx]) {
- printk(KERN_DEBUG "%s: other->table[%d] not o_tty for (%s)\n",
- __func__, idx, tty->name);
+ printk(KERN_DEBUG "%s: %s: bad other table[%d] = %p\n",
+ __func__, tty->name, idx,
+ tty->driver->other->ttys[idx]);
return -1;
}
if (o_tty->link != tty) {
- printk(KERN_DEBUG "%s: bad pty pointers\n", __func__);
+ printk(KERN_DEBUG "%s: %s: bad link = %p\n",
+ __func__, tty->name, o_tty->link);
return -1;
}
}
@@ -2099,7 +2101,8 @@ retry_open:
tty->driver->subtype == PTY_TYPE_MASTER)
noctty = 1;
#ifdef TTY_DEBUG_HANGUP
- printk(KERN_DEBUG "%s: opening %s...\n", __func__, tty->name);
+ printk(KERN_DEBUG "%s: %s: (tty count=%d)\n", __func__, tty->name,
+ tty->count);
#endif
if (tty->ops->open)
retval = tty->ops->open(tty, filp);
@@ -2109,8 +2112,8 @@ retry_open:

if (retval) {
#ifdef TTY_DEBUG_HANGUP
- printk(KERN_DEBUG "%s: error %d in opening %s...\n", __func__,
- retval, tty->name);
+ printk(KERN_DEBUG "%s: %s: error %d, releasing...\n", __func__,
+ tty->name, retval);
#endif
tty_unlock(tty); /* need to call tty_release without BTM */
tty_release(inode, filp);
--
2.4.5


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