linux-kernel - Re: [PATCH] kdesu broken

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Message-ID: <87fxci6ub9.fsf@devron.myhome.or.jp>
Date:	Tue, 28 Jul 2009 00:04:42 +0900
From:	OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
To:	Alan Cox <alan@...rguk.ukuu.org.uk>
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	"Rafael J. Wysocki" <rjw@...k.pl>, Ray Lee <ray-lk@...rabbit.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH] kdesu broken

Alan Cox <alan@...rguk.ukuu.org.uk> writes:

>> > +	set_bit(TTY_EOFPENDING, &pair->flags);
>> > +	set_bit(TTY_OTHER_CLOSED, &pair->flags);
>> > +	spin_unlock_irqrestore(&pair->buf.lock, flags);
>> 
>> 	tty_flip_buffer_push() or something?
>> 
>> > +	wake_up_interruptible(&pair->read_wait);
>> > +	wake_up_interruptible(&pair->write_wait);
>> 
>> It seems, this sets TTY_EOFPENDING, but if flush_to_ldisc() was done
>> already here, anybody doesn't set TTY_EOF for master.
>
> Does putting a tty_flip_buffer_push() at that point fix it. I had thought
> I could remove it but you are right that creates a situation where EOF
> may never get set.

With this patch, test program seems to work.

It seems "done = 0" hunk was needed for correct "done".

Thanks.


Signed-off-by: OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
---

 drivers/char/pty.c        |    1 +
 drivers/char/tty_buffer.c |    4 +---
 2 files changed, 2 insertions(+), 3 deletions(-)

diff -puN drivers/char/pty.c~pty-fixes4-fix drivers/char/pty.c
--- linux-2.6/drivers/char/pty.c~pty-fixes4-fix	2009-07-27 23:56:27.000000000 +0900
+++ linux-2.6-hirofumi/drivers/char/pty.c	2009-07-27 23:56:40.000000000 +0900
@@ -64,6 +64,7 @@ static void pty_close(struct tty_struct 
 	set_bit(TTY_EOFPENDING, &pair->flags);
 	set_bit(TTY_OTHER_CLOSED, &pair->flags);
 	spin_unlock_irqrestore(&pair->buf.lock, flags);
+	tty_flip_buffer_push(pair);
 	wake_up_interruptible(&pair->read_wait);
 	wake_up_interruptible(&pair->write_wait);
 	if (tty->driver->subtype == PTY_TYPE_MASTER) {
diff -puN drivers/char/tty_buffer.c~pty-fixes4-fix drivers/char/tty_buffer.c
--- linux-2.6/drivers/char/tty_buffer.c~pty-fixes4-fix	2009-07-27 23:57:27.000000000 +0900
+++ linux-2.6-hirofumi/drivers/char/tty_buffer.c	2009-07-27 23:57:30.000000000 +0900
@@ -443,10 +443,8 @@ static void flush_to_ldisc(struct work_s
 				done = 0;
 				break;
 			}
-			if (count > tty->receive_room) {
+			if (count > tty->receive_room)
 				count = tty->receive_room;
-				done = 0;
-			}
 			char_buf = head->char_buf_ptr + head->read;
 			flag_buf = head->flag_buf_ptr + head->read;
 			head->read += count;
_

-- 
OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
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