Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934363AbZJMVO4 (ORCPT ); Tue, 13 Oct 2009 17:14:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S934344AbZJMVOz (ORCPT ); Tue, 13 Oct 2009 17:14:55 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:34841 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761360AbZJMVOy (ORCPT ); Tue, 13 Oct 2009 17:14:54 -0400 Date: Tue, 13 Oct 2009 14:13:54 -0700 (PDT) From: Linus Torvalds X-X-Sender: torvalds@localhost.localdomain To: Boyan cc: =?ISO-8859-15?Q?Fr=E9d=E9ric_L=2E_W=2E_Meunier?= , "Justin P. Mattock" , Nix , Alan Cox , Paul Fulghum , "Rafael J. Wysocki" , Linux Kernel Mailing List , Kernel Testers List , Dmitry Torokhov , Ed Tomlinson , OGAWA Hirofumi Subject: Re: [Bug #14388] keyboard under X with 2.6.31 In-Reply-To: Message-ID: References: <56acieJJ2fF.A.nEB.Hzl0KB@chimera> <87ljjgfcbu.fsf@spindle.srvr.nix> <4AD3F769.5080405@gmail.com> <4AD437F9.9020708@yahoo.co.uk> <4AD4DE4C.4010402@yahoo.co.uk> User-Agent: Alpine 2.01 (LFD 1184 2008-12-16) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2864 Lines: 95 Another bug: On Tue, 13 Oct 2009, Linus Torvalds wrote: > if (!count) { > - if (head->next == NULL) > - break; Those two lines should _not_ be deleted. I cleaned up a bit too much. The rule is that we must not free the last buffer, because it's also going to be 'tail'. So here's a new version with that fixed (and the previous bug I already mentioned). Whether it _works_ is still not clear. It might eat your pet goldfish, or make farting noises in your general direction. Or it might fix the bug. Who knows? Linus --- drivers/char/tty_buffer.c | 29 +++++++++++++---------------- 1 files changed, 13 insertions(+), 16 deletions(-) diff --git a/drivers/char/tty_buffer.c b/drivers/char/tty_buffer.c index 3108991..0296612 100644 --- a/drivers/char/tty_buffer.c +++ b/drivers/char/tty_buffer.c @@ -402,28 +402,26 @@ static void flush_to_ldisc(struct work_struct *work) container_of(work, struct tty_struct, buf.work.work); unsigned long flags; struct tty_ldisc *disc; - struct tty_buffer *tbuf, *head; - char *char_buf; - unsigned char *flag_buf; disc = tty_ldisc_ref(tty); if (disc == NULL) /* !TTY_LDISC */ return; spin_lock_irqsave(&tty->buf.lock, flags); - /* So we know a flush is running */ - set_bit(TTY_FLUSHING, &tty->flags); - head = tty->buf.head; - if (head != NULL) { - tty->buf.head = NULL; - for (;;) { - int count = head->commit - head->read; + + if (!test_and_set_bit(TTY_FLUSHING, &tty->flags)) { + struct tty_buffer *head; + while ((head = tty->buf.head) != NULL) { + int count; + char *char_buf; + unsigned char *flag_buf; + + count = head->commit - head->read; if (!count) { if (head->next == NULL) break; - tbuf = head; - head = head->next; - tty_buffer_free(tty, tbuf); + tty->buf.head = head->next; + tty_buffer_free(tty, head); continue; } /* Ldisc or user is trying to flush the buffers @@ -445,9 +443,9 @@ static void flush_to_ldisc(struct work_struct *work) flag_buf, count); spin_lock_irqsave(&tty->buf.lock, flags); } - /* Restore the queue head */ - tty->buf.head = head; + clear_bit(TTY_FLUSHING, &tty->flags); } + /* We may have a deferred request to flush the input buffer, if so pull the chain under the lock and empty the queue */ if (test_bit(TTY_FLUSHPENDING, &tty->flags)) { @@ -455,7 +453,6 @@ static void flush_to_ldisc(struct work_struct *work) clear_bit(TTY_FLUSHPENDING, &tty->flags); wake_up(&tty->read_wait); } - clear_bit(TTY_FLUSHING, &tty->flags); spin_unlock_irqrestore(&tty->buf.lock, flags); tty_ldisc_deref(disc); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/