From: Peter Hurley <peter@hurleysoftware.com>
To: Johan Hovold <johan@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.cz>, Samuel Ortiz <samuel@sortiz.org>,
"David S. Miller" <davem@davemloft.net>,
Alan Cox <alan@linux.intel.com>,
linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org,
linux-serial@vger.kernel.org, netdev@vger.kernel.org,
ZIV-Asier Llano Palacios <asier.llano@cgglobal.com>,
stable <stable@vger.kernel.org>
Subject: Re: [PATCH 4/5] TTY: fix tty_wait_until_sent on 64-bit machines
Date: Thu, 05 Mar 2015 09:31:19 -0500 [thread overview]
Message-ID: <54F868B7.9010709@hurleysoftware.com> (raw)
In-Reply-To: <1425461947-15888-5-git-send-email-johan@kernel.org>
On 03/04/2015 04:39 AM, Johan Hovold wrote:
> Fix overflow bug in tty_wait_until_sent on 64-bit machines, where an
> infinite timeout (0) would be passed to the underlying tty-driver's
> wait_until_sent-operation as a negative timeout (-1), causing it to
> return immediately.
Wow, that is a nasty bug.
> This manifests itself for example as tcdrain() returning immediately,
> drivers not honouring the drain flags when setting terminal attributes,
> or even dropped data on close as a requested infinite closing-wait
> timeout would be ignored.
>
> The first symptom was reported by Asier LLANO who noted that tcdrain()
> returned prematurely when using the ftdi_sio usb-serial driver.
>
> Fix this by passing 0 rather than MAX_SCHEDULE_TIMEOUT (LONG_MAX) to the
> underlying tty driver.
>
> Note that the serial-core wait_until_sent-implementation is not affected
> by this bug due to a lucky chance (comparison to an unsigned maximum
> timeout), and neither is the cyclades one that had an explicit check for
> negative timeouts, but all other tty drivers appear to be affected.
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
next prev parent reply other threads:[~2015-03-05 14:31 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-04 9:39 [PATCH 0/5] TTY: fix tty_wait_until_sent on 64-bit machines Johan Hovold
2015-03-04 9:39 ` [PATCH 1/5] net: irda: fix wait_until_sent poll timeout Johan Hovold
2015-03-04 9:39 ` [PATCH 2/5] TTY: bfin_jtag_comm: remove incorrect wait_until_sent operation Johan Hovold
2015-03-05 14:33 ` Peter Hurley
2015-03-04 9:39 ` [PATCH 3/5] USB: serial: fix infinite wait_until_sent timeout Johan Hovold
2015-03-04 9:39 ` [PATCH 4/5] TTY: fix tty_wait_until_sent on 64-bit machines Johan Hovold
2015-03-05 14:31 ` Peter Hurley [this message]
2015-03-04 9:39 ` [PATCH 5/5] TTY: fix tty_wait_until_sent maximum timeout Johan Hovold
2015-03-05 14:32 ` Peter Hurley
2015-03-07 2:43 ` [PATCH 0/5] TTY: fix tty_wait_until_sent on 64-bit machines Greg Kroah-Hartman
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