lkml.org 
[lkml]   [2009]   [Jun]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[bug] WARNING: at drivers/char/tty_io.c:1266 tty_open+0x1ea/0x388()

* Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:

> On Sun, 14 Jun 2009 10:10:52 +0200
> Ingo Molnar <mingo@elte.hu> wrote:
>
> >
> > Ok, this is one for those who like to look at weird crashes/bugs.
> >
> > Here's a new regression that popped up in this merge window, there's
> > some sort of slab corruption going on in tty data structures:
>
> I split the ldisc and tty apart and redid the ldisc locking so its a fair
> bet I know what changeset is to blame, will just need to hunt it down a
> bit. kmemcheck found one leak case on Friday which I've fixed but not yet
> scribbles.
>
> > c65c9bc: tty: rewrite the ldisc locking
>
> Almost certainly that one and will investigate on Monday

I have applied your patch from yesterday (attached further below for
reference) and the SLAB corruption has not triggered - instead i'm
now getting this warning, after 96 reboots:

[ 20.782199] sshd used greatest stack depth: 5376 bytes left
[ 22.260149] ------------[ cut here ]------------
[ 22.261027] WARNING: at drivers/char/tty_io.c:1266 tty_open+0x1ea/0x388()
[ 22.262018] Hardware name: System Product Name
[ 22.262020] Modules linked in:
[ 22.262024] Pid: 2553, comm: modprobe Tainted: G W 2.6.30-tip #54059
[ 22.262026] Call Trace:
[ 22.262032] [<c102d810>] warn_slowpath_common+0x60/0x90
[ 22.262037] [<c102d84d>] warn_slowpath_null+0xd/0x10
[ 22.262041] [<c11a88ae>] tty_open+0x1ea/0x388
[ 22.262045] [<c108e4c2>] chrdev_open+0x11b/0x132
[ 22.262049] [<c108a8a6>] __dentry_open+0x167/0x265
[ 22.262052] [<c108aa3e>] nameidata_to_filp+0x2c/0x43
[ 22.262056] [<c108e3a7>] ? chrdev_open+0x0/0x132
[ 22.262060] [<c1094bbd>] do_filp_open+0x3cd/0x712
[ 22.262064] [<c1083460>] ? check_valid_pointer+0x1f/0x4e
[ 22.262068] [<c109cd26>] ? alloc_fd+0xcb/0xd5
[ 22.262071] [<c109cd26>] ? alloc_fd+0xcb/0xd5
[ 22.262075] [<c108a63d>] do_sys_open+0x4a/0xed
[ 22.262078] [<c1002a5e>] ? sysenter_exit+0xf/0x21
[ 22.262081] [<c108a722>] sys_open+0x1e/0x26
[ 22.262085] [<c1002a2b>] sysenter_do_call+0x12/0x36
[ 22.262087] ---[ end trace 81f0afc9843492f2 ]---
[ 31.191037] CPA self-test:

Another test-box has produced this warning too. (Same config and
same hw as i sent the details for earlier in this thread.)

So there's still something fishy going on.

Thanks,

Ingo

-------------------->
From 9f7a9ce1955c5f7af7456363a552819a82c19896 Mon Sep 17 00:00:00 2001
From: Alan Cox <alan@linux.intel.com>
Date: Mon, 15 Jun 2009 16:32:12 +0100
Subject: [PATCH] ldisc: Make sure the ldisc isn't active when we close it

Signed-off-by: Alan Cox <alan@linux.intel.com>
LKML-Reference: <20090615153206.4036.26148.stgit@t61.ukuu.org.uk>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
drivers/char/tty_ldisc.c | 2 ++
1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/drivers/char/tty_ldisc.c b/drivers/char/tty_ldisc.c
index 69b912d..0ea4f63 100644
--- a/drivers/char/tty_ldisc.c
+++ b/drivers/char/tty_ldisc.c
@@ -792,6 +792,8 @@ void tty_ldisc_hangup(struct tty_struct *tty)
/* Avoid racing set_ldisc */
mutex_lock(&tty->ldisc_mutex);
/* Switch back to N_TTY */
+ tty_ldisc_halt(tty);
+ tty_ldisc_wait_idle(tty);
tty_ldisc_reinit(tty);
/* At this point we have a closed ldisc and we want to
reopen it. We could defer this to the next open but

\
 
 \ /
  Last update: 2009-06-16 09:13    [W:0.120 / U:0.352 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site