Messages in this thread Patch in this message | | | Date | Sat, 22 Jul 2006 12:07:00 -0400 | From | Chuck Ebbert <> | Subject | Re: Success: tty_io flush_to_ldisc() error message triggered |
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In-Reply-To: <44C2307C.9060607@microgate.com>
On Sat, 22 Jul 2006 09:04:44 -0500, Paul Fulghum wrote:
> That confirms my thoughts on what went wrong: > multiple copies of the queued work (flush_to_ldisc) > running in parallel and corrupting the free buffer list. > > A cleaner fix for this is already > in the 2.6.18 rc series.
The cleaner fix looks more intrusive, though.
Is this simpler change (what I'm running but without the warning messages) the preferred fix for -stable?
From: Paul Fulghum <paulkf@microgate.com>
Serialize flush_to_ldisc() per-device. Fixes free list corruption that causes lockup on SMP systems.
Signed-off-by: Paul Fulghum <paulkf@microgate.com> Acked-by: Chuck Ebbert <76306.1226@compuserve.com>
--- 2.6.16.20-d4.orig/include/linux/tty.h +++ 2.6.16.20-d4/include/linux/tty.h @@ -266,6 +266,7 @@ struct tty_struct { #define TTY_PTY_LOCK 16 /* pty private */ #define TTY_NO_WRITE_SPLIT 17 /* Preserve write boundaries to driver */ #define TTY_HUPPED 18 /* Post driver->hangup() */ +#define TTY_FLUSHING 19 /* Flushing tty buffers to line discipline */ #define TTY_WRITE_FLUSH(tty) tty_write_flush((tty)) --- 2.6.16.20-d4.orig/drivers/char/tty_io.c +++ 2.6.16.20-d4/drivers/char/tty_io.c @@ -2780,10 +2780,8 @@ static void flush_to_ldisc(void *private if (disc == NULL) /* !TTY_LDISC */ return; - if (test_bit(TTY_DONT_FLIP, &tty->flags)) { - /* - * Do it after the next timer tick: - */ + if (test_bit(TTY_DONT_FLIP, &tty->flags) || + test_and_set_bit(TTY_FLUSHING, &tty->flags)) { schedule_delayed_work(&tty->buf.work, 1); goto out; } @@ -2805,6 +2803,7 @@ static void flush_to_ldisc(void *private tty_buffer_free(tty, tbuf); } spin_unlock_irqrestore(&tty->buf.lock, flags); + clear_bit(TTY_FLUSHING, &tty->flags); out: tty_ldisc_deref(disc); } -- Chuck - 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/
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