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authorPeter Hurley <peter@hurleysoftware.com>2013-03-11 16:44:38 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-03-18 16:46:30 -0700
commitfc575ee6eadbcac757e3216e230b6fab1ba5b140 (patch)
treee01260de659705bbece162866d3abbbda9a69b22 /drivers/tty/tty_ldisc.c
parent96433d104a4b39c43dd6f57776f9fcb765111a56 (diff)
tty: Add ldisc hangup debug messages
Expected typical debug log: [ 582.721965] tty_open: opening pts3... [ 582.721970] tty_open: opening pts3... [ 582.721977] tty_release: pts3 (tty count=3)... [ 582.721980] tty_release: ptm3 (tty count=1)... [ 582.722015] pts3 vhangup... [ 582.722020] tty_ldisc_hangup: pts3: closing ldisc: ffff88007a920540 [ 582.724128] tty_release: pts3 (tty count=2)... [ 582.724217] tty_ldisc_hangup: pts3: re-opened ldisc: ffff88007a920580 [ 582.724221] tty_release: ptm3: final close [ 582.724234] tty_ldisc_release: ptm3: closing ldisc: ffff88007a920a80 [ 582.724238] tty_ldisc_release: ptm3: ldisc closed [ 582.724241] tty_release: ptm3: freeing structure... [ 582.724741] tty_open: opening pts3... Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/tty_ldisc.c')
-rw-r--r--drivers/tty/tty_ldisc.c19
1 files changed, 19 insertions, 0 deletions
diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c
index 0030d556b9b3..328ff5b544a5 100644
--- a/drivers/tty/tty_ldisc.c
+++ b/drivers/tty/tty_ldisc.c
@@ -20,6 +20,17 @@
#include <linux/uaccess.h>
#include <linux/ratelimit.h>
+#undef LDISC_DEBUG_HANGUP
+
+#ifdef LDISC_DEBUG_HANGUP
+#define tty_ldisc_debug(tty, f, args...) ({ \
+ char __b[64]; \
+ printk(KERN_DEBUG "%s: %s: " f, __func__, tty_name(tty, __b), ##args); \
+})
+#else
+#define tty_ldisc_debug(tty, f, args...)
+#endif
+
/*
* This guards the refcounted line discipline lists. The lock
* must be taken with irqs off because there are hangup path
@@ -822,6 +833,8 @@ void tty_ldisc_hangup(struct tty_struct *tty)
int reset = tty->driver->flags & TTY_DRIVER_RESET_TERMIOS;
int err = 0;
+ tty_ldisc_debug(tty, "closing ldisc: %p\n", tty->ldisc);
+
/*
* FIXME! What are the locking issues here? This may me overdoing
* things... This question is especially important now that we've
@@ -878,6 +891,8 @@ void tty_ldisc_hangup(struct tty_struct *tty)
mutex_unlock(&tty->ldisc_mutex);
if (reset)
tty_reset_termios(tty);
+
+ tty_ldisc_debug(tty, "re-opened ldisc: %p\n", tty->ldisc);
}
/**
@@ -944,6 +959,8 @@ void tty_ldisc_release(struct tty_struct *tty, struct tty_struct *o_tty)
* it does not race with the set_ldisc code path.
*/
+ tty_ldisc_debug(tty, "closing ldisc: %p\n", tty->ldisc);
+
tty_ldisc_halt(tty, o_tty, MAX_SCHEDULE_TIMEOUT);
tty_lock_pair(tty, o_tty);
@@ -955,6 +972,8 @@ void tty_ldisc_release(struct tty_struct *tty, struct tty_struct *o_tty)
tty_unlock_pair(tty, o_tty);
/* And the memory resources remaining (buffers, termios) will be
disposed of when the kref hits zero */
+
+ tty_ldisc_debug(tty, "ldisc closed\n");
}
/**