diff options
| author | Philippe Rétornaz <philippe.retornaz@epfl.ch> | 2010-10-27 17:13:21 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-03-21 12:43:53 -0700 |
| commit | 28bda4eca2f7b1677087cc229cedf1a932fcc8fb (patch) | |
| tree | 4e6d33776828e88464a4f68b6a5f19293327e301 /drivers/char | |
| parent | 827136988433fec7a45b3b20b59bdf03e33cf918 (diff) | |
| download | lwn-28bda4eca2f7b1677087cc229cedf1a932fcc8fb.tar.gz lwn-28bda4eca2f7b1677087cc229cedf1a932fcc8fb.zip | |
tty_ldisc: Fix BUG() on hangup
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>
Diffstat (limited to 'drivers/char')
| -rw-r--r-- | drivers/char/tty_ldisc.c | 20 |
1 files changed, 13 insertions, 7 deletions
diff --git a/drivers/char/tty_ldisc.c b/drivers/char/tty_ldisc.c index df5e7db40d13..7af1a1563e8f 100644 --- a/drivers/char/tty_ldisc.c +++ b/drivers/char/tty_ldisc.c @@ -741,9 +741,12 @@ 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); @@ -751,10 +754,10 @@ 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; } /** @@ -816,13 +819,16 @@ 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); |