From: Greg KH <gregkh@linuxfoundation.org>
To: Sasha Levin <levinsasha928@gmail.com>
Cc: Jiri Slaby <jslaby@suse.cz>,
alan@linux.intel.com, linux-kernel@vger.kernel.org,
jirislaby@gmail.com, Dave Jones <davej@redhat.com>
Subject: Re: [PATCH 21/21] TTY: move tty buffers to tty_port
Date: Thu, 25 Oct 2012 11:08:01 -0700 [thread overview]
Message-ID: <20121025180801.GA22642@kroah.com> (raw)
In-Reply-To: <50897E98.5080502@gmail.com>
On Thu, Oct 25, 2012 at 02:02:00PM -0400, Sasha Levin wrote:
> Hi guys,
>
> On 10/18/2012 04:26 PM, Jiri Slaby wrote:
> > So this is it. The big step why we did all the work over the past
> > kernel releases. Now everything is prepared, so nothing protects us
> > from doing that big step.
> >
> > | | \ \ nnnn/^l | |
> > | | \ / / | |
> > | '-,.__ => \/ ,-` => | '-,.__
> > | O __.´´) ( .` | O __.´´)
> > ~~~ ~~ `` ~~~ ~~
> > The buffers are now in the tty_port structure and we can start
> > teaching the buffer helpers (insert char/string, flip etc.) to use
> > tty_port instead of tty_struct all around.
> >
> > Signed-off-by: Jiri Slaby <jslaby@suse.cz>
> > ---
>
> Fuzzing with trinity inside a KVM tools (lkvm) guest with -next kernel
> uncovered the following warning:
>
> [ 1339.448706] ------------[ cut here ]------------
> [ 1339.451224] WARNING: at drivers/tty/tty_buffer.c:476 flush_to_ldisc+0x60/0x200()
> [ 1339.454272] tty is NULLPid: 7147, comm: kworker/4:0 Tainted: G W 3.7.0-rc2-next-20121025-sasha-00001-g673f98e-dirty #75
> [ 1339.458693] Call Trace:
> [ 1339.459410] [<ffffffff81bb1ea0>] ? flush_to_ldisc+0x60/0x200
> [ 1339.461289] [<ffffffff81109b86>] warn_slowpath_common+0x86/0xb0
> [ 1339.462992] [<ffffffff81109c11>] warn_slowpath_fmt+0x41/0x50
> [ 1339.464772] [<ffffffff81bb1ea0>] flush_to_ldisc+0x60/0x200
> [ 1339.467076] [<ffffffff8112d5a9>] process_one_work+0x3b9/0x770
> [ 1339.469501] [<ffffffff8112d458>] ? process_one_work+0x268/0x770
> [ 1339.472053] [<ffffffff8112dcc1>] ? worker_thread+0x51/0x3f0
> [ 1339.473831] [<ffffffff81bb1e40>] ? __tty_buffer_request_room+0x180/0x180
> [ 1339.475834] [<ffffffff8112df2a>] worker_thread+0x2ba/0x3f0
> [ 1339.478027] [<ffffffff8112dc70>] ? rescuer_thread+0x2d0/0x2d0
> [ 1339.480431] [<ffffffff81138c33>] kthread+0xe3/0xf0
> [ 1339.482383] [<ffffffff8117d7be>] ? put_lock_stats.isra.16+0xe/0x40
> [ 1339.484171] [<ffffffff81138b50>] ? insert_kthread_work+0x90/0x90
> [ 1339.485886] [<ffffffff83aedebc>] ret_from_fork+0x7c/0xb0
> [ 1339.487943] [<ffffffff81138b50>] ? insert_kthread_work+0x90/0x90
> [ 1339.490435] ---[ end trace e01a8b0af77894c4 ]---
>
> I'm guessing it happens because we never cancel the scheduled work when we
> free the buffer, so the scheduled work may run even after we freed the buffer.
>
> Besides the warning itself, I think that 'tty is NULL' would need a newline
> after it. Greg, should I send a patch for that?
Yes, please do.
thanks,
greg k-h
next prev parent reply other threads:[~2012-10-25 18:08 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-18 20:26 [PATCH 00/21] TTY buffer in tty_port and other stuff Jiri Slaby
2012-10-18 20:26 ` [PATCH 01/21] TTY: devpts, don't care about TTY in devpts_get_tty Jiri Slaby
2012-10-18 20:26 ` [PATCH 02/21] TTY: devpts, return created inode from devpts_pty_new Jiri Slaby
2012-10-18 20:26 ` [PATCH 03/21] TTY: devpts, do not set driver_data Jiri Slaby
2012-10-18 20:26 ` [PATCH 04/21] TTY: devpts, document devpts inode operations Jiri Slaby
2012-10-18 20:26 ` [PATCH 05/21] TTY: move devpts kill to pty Jiri Slaby
2012-10-18 20:26 ` [PATCH 06/21] TTY: vt, fix paste_selection ldisc handling Jiri Slaby
2012-10-18 20:26 ` [PATCH 07/21] TTY: ldisc, wait for idle ldisc in release Jiri Slaby
2012-10-18 20:26 ` [PATCH 08/21] TTY: hci_ldisc, remove invalid check in open Jiri Slaby
2012-10-18 20:47 ` Marcel Holtmann
2012-10-18 20:26 ` [PATCH 09/21] TTY: n_tty, simplify read_buf+echo_buf allocation Jiri Slaby
2012-10-18 20:26 ` [PATCH 10/21] TTY: n_tty, remove bogus checks Jiri Slaby
2012-10-18 20:26 ` [PATCH 11/21] TTY: audit, stop accessing tty->icount Jiri Slaby
2012-10-18 20:26 ` [PATCH 12/21] TTY: n_tty, add ldisc data to n_tty Jiri Slaby
2012-10-18 20:26 ` [PATCH 13/21] TTY: move ldisc data from tty_struct: simple members Jiri Slaby
2012-10-18 20:26 ` [PATCH 14/21] TTY: move ldisc data from tty_struct: bitmaps Jiri Slaby
2012-10-18 20:26 ` [PATCH 15/21] TTY: move ldisc data from tty_struct: read_* and echo_* and canon_* stuff Jiri Slaby
2012-10-18 20:26 ` [PATCH 16/21] TTY: move ldisc data from tty_struct: locks Jiri Slaby
2012-10-18 20:26 ` [PATCH 17/21] TTY: n_tty, propagate n_tty_data Jiri Slaby
2012-10-18 20:26 ` [PATCH 18/21] TTY: move TTY_FLUSH* flags to tty_port Jiri Slaby
2012-10-18 20:26 ` [PATCH 19/21] TTY: tty_buffer, cache pointer to tty->buf Jiri Slaby
2012-10-18 20:26 ` [PATCH 20/21] TTY: add port -> tty link Jiri Slaby
2012-10-18 20:26 ` [PATCH 21/21] TTY: move tty buffers to tty_port Jiri Slaby
2012-10-25 18:02 ` Sasha Levin
2012-10-25 18:08 ` Greg KH [this message]
2012-10-31 12:53 ` Jiri Slaby
2012-10-31 15:30 ` Sasha Levin
2012-10-31 15:32 ` Jiri Slaby
2012-10-31 15:59 ` Sasha Levin
2012-11-02 15:51 ` Jiri Slaby
2012-11-02 16:07 ` Sasha Levin
2012-11-02 16:18 ` Jiri Slaby
2012-11-02 16:23 ` Sasha Levin
2012-11-03 2:03 ` Sasha Levin
2012-11-03 15:55 ` Jiri Slaby
2012-11-03 23:06 ` Sasha Levin
2012-11-04 0:53 ` Sasha Levin
2012-11-27 19:57 ` Peter Hurley
2012-11-30 23:52 ` Sasha Levin
2012-12-01 14:59 ` flush_to_ldisc accesses tty after free (was: [PATCH 21/21] TTY: move tty buffers to tty_port) Peter Hurley
2012-12-01 20:06 ` Peter Hurley
2012-12-02 19:57 ` Peter Hurley
2012-12-04 19:21 ` Ilya Zykov
2012-10-31 20:10 ` [PATCH 21/21] TTY: move tty buffers to tty_port Sasha Levin
2012-10-18 21:12 ` [PATCH 00/21] TTY buffer in tty_port and other stuff Greg KH
2012-10-22 14:57 ` Alan Cox
2012-10-22 23:59 ` Greg KH
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