From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: Dmitry Vyukov <dvyukov@google.com>,
syzbot <syzbot+b7c3ba8cdc2f6cf83c21@syzkaller.appspotmail.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jiri Slaby <jirislaby@kernel.org>,
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [kernel?] KCSAN: data-race in __fput / __tty_hangup (4)
Date: Mon, 24 Apr 2023 10:09:12 +0900 [thread overview]
Message-ID: <8e21256a-736e-4c2d-1ff4-723775bcac46@I-love.SAKURA.ne.jp> (raw)
In-Reply-To: <20230424004431.GG3390869@ZenIV>
On 2023/04/24 9:44, Al Viro wrote:
> Do you mean doing that in method instances that are present in tty_fops
> you mean doing that in method instances that are present in tty_fops
> and different in hung_up_tty_fops?
I meant, remove hung_up_tty_fops, and embed callbacks defined in hung_up_tty_fops into
tty_fops. For example, tty_read() (from "struct file_operations tty_fops"->read_iter)
will be changed like
static ssize_t tty_read(struct kiocb *iocb, struct iov_iter *to)
{
int i;
struct file *file = iocb->ki_filp;
struct inode *inode = file_inode(file);
struct tty_struct *tty = file_tty(file);
struct tty_ldisc *ld;
+ if (data_race(file->tty_hangup)) {
+ return hung_up_tty_read(iocb, to);
+ }
+
if (tty_paranoia_check(tty, inode, "tty_read"))
return -EIO;
if (!tty || tty_io_error(tty))
return -EIO;
/* We want to wait for the line discipline to sort out in this
* situation.
*/
ld = tty_ldisc_ref_wait(tty);
if (!ld)
return hung_up_tty_read(iocb, to);
i = -EIO;
if (ld->ops->read)
i = iterate_tty_read(ld, tty, file, to);
tty_ldisc_deref(ld);
if (i > 0)
tty_update_time(&inode->i_atime);
return i;
}
in order to avoid wrapping filp->f_op->* dereferences using data_race().
next prev parent reply other threads:[~2023-04-24 1:13 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-21 8:18 [syzbot] [kernel?] KCSAN: data-race in __fput / __tty_hangup (4) syzbot
2023-04-21 8:21 ` Dmitry Vyukov
2023-04-21 15:12 ` Tetsuo Handa
2023-04-21 16:02 ` Tetsuo Handa
2023-04-23 23:34 ` Al Viro
2023-04-23 23:55 ` Tetsuo Handa
2023-04-24 0:44 ` Al Viro
2023-04-24 1:09 ` Tetsuo Handa [this message]
2023-04-25 14:47 ` Tetsuo Handa
2023-04-25 16:03 ` Al Viro
2023-04-25 22:09 ` Tetsuo Handa
2023-04-26 11:05 ` [PATCH] tty: tty_io: remove hung_up_tty_fops Tetsuo Handa
2023-04-28 16:27 ` Nathan Chancellor
2023-04-28 16:41 ` Tetsuo Handa
2023-04-28 17:11 ` Al Viro
2023-04-29 10:43 ` Tetsuo Handa
2023-04-28 17:31 ` Greg Kroah-Hartman
2023-04-29 15:21 ` Guenter Roeck
2023-05-01 18:42 ` Geert Uytterhoeven
2023-05-14 1:02 ` [PATCH v2] " Tetsuo Handa
2023-05-30 10:44 ` Greg Kroah-Hartman
2023-05-30 11:57 ` Tetsuo Handa
2023-05-30 12:51 ` Greg Kroah-Hartman
2024-04-27 6:20 ` [PATCH v3] " Tetsuo Handa
2024-04-27 19:02 ` Linus Torvalds
2024-04-28 10:19 ` Tetsuo Handa
2024-04-28 18:50 ` Linus Torvalds
2024-04-29 13:55 ` Marco Elver
2024-04-29 15:38 ` Linus Torvalds
2024-05-01 18:45 ` Paul E. McKenney
2024-05-01 18:56 ` Linus Torvalds
2024-05-01 19:02 ` Paul E. McKenney
2024-05-01 20:14 ` Marco Elver
2024-05-01 21:06 ` Linus Torvalds
2024-05-01 21:20 ` Linus Torvalds
2024-05-01 21:49 ` Paul E. McKenney
2024-05-01 22:32 ` Paul E. McKenney
2024-05-02 16:37 ` Boqun Feng
2024-05-03 23:59 ` Paul E. McKenney
2024-05-04 0:14 ` Linus Torvalds
2024-05-04 5:08 ` Paul E. McKenney
2024-05-04 17:50 ` Linus Torvalds
2024-05-04 18:18 ` Paul E. McKenney
2024-05-04 19:11 ` Linus Torvalds
2024-05-04 19:25 ` Linus Torvalds
2024-05-04 22:17 ` Paul E. McKenney
2024-05-04 22:04 ` Paul E. McKenney
2024-05-02 14:14 ` Marco Elver
2024-05-02 16:42 ` Tetsuo Handa
2024-05-02 17:20 ` Marco Elver
2024-05-02 17:29 ` Linus Torvalds
2024-05-02 18:14 ` Al Viro
2024-05-02 19:29 ` Marco Elver
2024-05-02 23:54 ` Tetsuo Handa
2024-05-03 1:12 ` Linus Torvalds
2023-04-23 13:28 ` [syzbot] [kernel?] KCSAN: data-race in __fput / __tty_hangup (4) Tetsuo Handa
2023-04-23 14:00 ` Greg Kroah-Hartman
2023-04-23 14:03 ` Greg Kroah-Hartman
2023-04-23 14:17 ` Tetsuo Handa
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