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SubjectRe: [043/127] TTY: ldisc, fix open flag handling
On 12/08/2010 01:43 AM, Greg KH wrote:
> 2.6.32-stable review patch. If anyone has any objections, please let us know.
>
> ------------------
>
> From: Jiri Slaby <jslaby@suse.cz>
>
> commit 7f90cfc505d613f4faf096e0d84ffe99208057d9 upstream.
>
> When a concrete ldisc open fails in tty_ldisc_open, we forget to clear
> TTY_LDISC_OPEN. This causes a false warning on the next ldisc open:
> WARNING: at drivers/char/tty_ldisc.c:445 tty_ldisc_open+0x26/0x38()
> Hardware name: System Product Name
> Modules linked in: ...
> Pid: 5251, comm: a.out Tainted: G W 2.6.32-5-686 #1
> Call Trace:
> [<c1030321>] ? warn_slowpath_common+0x5e/0x8a
> [<c1030357>] ? warn_slowpath_null+0xa/0xc
> [<c119311c>] ? tty_ldisc_open+0x26/0x38
> [<c11936c5>] ? tty_set_ldisc+0x218/0x304
> ...
>
> So clear the bit when failing...
>
> Introduced in c65c9bc3efa (tty: rewrite the ldisc locking) back in
> 2.6.31-rc1.
>
> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
> Cc: Alan Cox <alan@linux.intel.com>
> Reported-by: Sergey Lapin <slapin@ossfans.org>
> Tested-by: Sergey Lapin <slapin@ossfans.org>
> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
>
> ---
> drivers/char/tty_ldisc.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> --- a/drivers/char/tty_ldisc.c
> +++ b/drivers/char/tty_ldisc.c
> @@ -444,9 +444,14 @@ static void tty_set_termios_ldisc(struct
>
> static int tty_ldisc_open(struct tty_struct *tty, struct tty_ldisc *ld)
> {
> + int ret;
> +
> WARN_ON(test_and_set_bit(TTY_LDISC_OPEN, &tty->flags));
> - if (ld->ops->open)
> - return ld->ops->open(tty);
> + if (ld->ops->open) {
> + ret = ld->ops->open(tty);
> + if (ret)
> + clear_bit(TTY_LDISC_OPEN, &tty->flags);
> + }
> return 0;

Whoops, this should write return ret; (with int ret = 0;)

Do you want me to send the patch against rebased on .32?

thanks,
--
js
suse labs


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