projects / thirdparty / kernel / stable-queue.git / blame
| Commit | Line | Data |
|---|---|---|
| b5d7ff57 GKH |
1 | From 1c95ba1e1de7edffc0c4e275e147f1a9eb1f81ae Mon Sep 17 00:00:00 2001 |
| 2 | From: =?UTF-8?q?Philippe=20R=C3=A9tornaz?= <philippe.retornaz@epfl.ch> | |
| 3 | Date: Wed, 27 Oct 2010 17:13:21 +0200 | |
| 4 | Subject: tty_ldisc: Fix BUG() on hangup | |
| 5 | ||
| 6 | From: =?UTF-8?q?Philippe=20R=C3=A9tornaz?= <philippe.retornaz@epfl.ch> | |
| 7 | ||
| 8 | commit 1c95ba1e1de7edffc0c4e275e147f1a9eb1f81ae upstream. | |
| 9 | ||
| 10 | A kernel BUG when bluetooth rfcomm connection drop while the associated | |
| 11 | serial port is open is sometime triggered. | |
| 12 | ||
| 13 | It seems that the line discipline can disappear between the | |
| 14 | tty_ldisc_put and tty_ldisc_get. This patch fall back to the N_TTY line | |
| 15 | discipline if the previous discipline is not available anymore. | |
| 16 | ||
| 17 | Signed-off-by: Philippe Retornaz <philippe.retornaz@epfl.ch> | |
| 18 | Acked-by: Alan Cox <alan@linux.intel.com> | |
| 19 | Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> | |
| 20 | ||
| 21 | --- | |
| 22 | drivers/char/tty_ldisc.c | 20 +++++++++++++------- | |
| 23 | 1 file changed, 13 insertions(+), 7 deletions(-) | |
| 24 | ||
| 25 | --- a/drivers/char/tty_ldisc.c | |
| 26 | +++ b/drivers/char/tty_ldisc.c | |
| 27 | @@ -743,9 +743,12 @@ static void tty_reset_termios(struct tty | |
| 28 | * state closed | |
| 29 | */ | |
| 30 | ||
| 31 | -static void tty_ldisc_reinit(struct tty_struct *tty, int ldisc) | |
| 32 | +static int tty_ldisc_reinit(struct tty_struct *tty, int ldisc) | |
| 33 | { | |
| 34 | - struct tty_ldisc *ld; | |
| 35 | + struct tty_ldisc *ld = tty_ldisc_get(ldisc); | |
| 36 | + | |
| 37 | + if (IS_ERR(ld)) | |
| 38 | + return -1; | |
| 39 | ||
| 40 | tty_ldisc_close(tty, tty->ldisc); | |
| 41 | tty_ldisc_put(tty->ldisc); | |
| 42 | @@ -753,10 +756,10 @@ static void tty_ldisc_reinit(struct tty_ | |
| 43 | /* | |
| 44 | * Switch the line discipline back | |
| 45 | */ | |
| 46 | - ld = tty_ldisc_get(ldisc); | |
| 47 | - BUG_ON(IS_ERR(ld)); | |
| 48 | tty_ldisc_assign(tty, ld); | |
| 49 | tty_set_termios_ldisc(tty, ldisc); | |
| 50 | + | |
| 51 | + return 0; | |
| 52 | } | |
| 53 | ||
| 54 | /** | |
| 55 | @@ -831,13 +834,16 @@ void tty_ldisc_hangup(struct tty_struct | |
| 56 | a FIXME */ | |
| 57 | if (tty->ldisc) { /* Not yet closed */ | |
| 58 | if (reset == 0) { | |
| 59 | - tty_ldisc_reinit(tty, tty->termios->c_line); | |
| 60 | - err = tty_ldisc_open(tty, tty->ldisc); | |
| 61 | + | |
| 62 | + if (!tty_ldisc_reinit(tty, tty->termios->c_line)) | |
| 63 | + err = tty_ldisc_open(tty, tty->ldisc); | |
| 64 | + else | |
| 65 | + err = 1; | |
| 66 | } | |
| 67 | /* If the re-open fails or we reset then go to N_TTY. The | |
| 68 | N_TTY open cannot fail */ | |
| 69 | if (reset || err) { | |
| 70 | - tty_ldisc_reinit(tty, N_TTY); | |
| 71 | + BUG_ON(tty_ldisc_reinit(tty, N_TTY)); | |
| 72 | WARN_ON(tty_ldisc_open(tty, tty->ldisc)); | |
| 73 | } | |
| 74 | tty_ldisc_enable(tty); |