Messages in this thread Patch in this message | | | Date | Wed, 08 Dec 2010 16:09:26 +0100 | From | Jiri Slaby <> | Subject | Re: [043/127] TTY: ldisc, fix open flag handling |
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On 12/08/2010 04:02 PM, Greg KH wrote: > On Wed, Dec 08, 2010 at 07:24:46AM +0100, Jiri Slaby wrote: >> 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? > > No, send it based on Linus's tree as it's wrong there, right? Then it > will move through to the stable kernels.
Nope, in 2.6.36 and newer it looks differently, only the .32 backport is broken.
The .36 backport is OK: --- a/drivers/char/tty_ldisc.c +++ b/drivers/char/tty_ldisc.c @@ -454,6 +454,8 @@ static int tty_ldisc_open(struct tty_str /* BTM here locks versus a hangup event */ WARN_ON(!tty_locked()); ret = ld->ops->open(tty); + if (ret) + clear_bit(TTY_LDISC_OPEN, &tty->flags); return ret; } return 0; thanks, -- js suse labs
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