From: "David S. Miller" <davem@redhat.com>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: akpm@osdl.org, linux-kernel@vger.kernel.org, rmk+serial@arm.linux.org.uk
Subject: Re: [PATCH] Fix typo in pmac_zilog
Date: Sun, 30 May 2004 17:32:52 -0700 [thread overview]
Message-ID: <20040530173252.4a040e99.davem@redhat.com> (raw)
In-Reply-To: <1085901218.10399.11.camel@gaston>
On Sun, 30 May 2004 17:13:38 +1000
Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote:
> There is a deadlock issue. I triggered once when I had a bug where the
> driver was flooding the input with zero's. All serial drivers seem to be
> affected. Apparently, tty_flip_* may call back into your write() routine
Yes indeed, one code path is:
tty_flip_buffer_push()
if (tty->low_latency)
flush_to_ldisc() {
tty->ldisc.receive_buf() == n_tty_receive_buf() {
...
n_tty_receive_char() {
...
start_tty() {
tty->driver->start() == uart_start()
and that's where we try to grab the uart port lock again.
It seems lots of serial drivers have this bug, even 8250.c :-)
I'll fix up the Sparc drivers meanwhile.
next prev parent reply other threads:[~2004-05-31 0:33 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-05-28 3:40 Benjamin Herrenschmidt
2004-05-30 6:42 ` David S. Miller
2004-05-30 7:13 ` Benjamin Herrenschmidt
2004-05-31 0:32 ` David S. Miller [this message]
2004-05-31 0:30 ` Benjamin Herrenschmidt
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