lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Sun, 20 Jun 2010 22:54:34 +0200
From:	Arnd Bergmann <arnd@...db.de>
To:	Alan Cox <alan@...rguk.ukuu.org.uk>
Cc:	Tony Luck <tony.luck@...el.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	linux-kernel@...r.kernel.org, Greg KH <gregkh@...e.de>,
	Thomas Gleixner <tglx@...utronix.de>,
	Andrew Morton <akpm@...ux-foundation.org>,
	John Kacur <jkacur@...hat.com>,
	Al Viro <viro@...iv.linux.org.uk>, Ingo Molnar <mingo@...e.hu>
Subject: Re: [PATCH] serial: revert "Use block_til_ready helper"

On Saturday 19 June 2010 23:57:06 Alan Cox wrote:
> 
> Important question - does it need a getty or will a simple cat < /dev/foo
> twice get garbled (or cat > if its garbling the other way)
>
> Which direction matters and whether a hangup is needed matters

What I see is totally reproducible but does not make any sense to me.
In my test setup I have a serial cable between /dev/ttyS0 (on-board
16550A) and /dev/ttyUSB0 on the same machine.

When I start minicom on ttyS0 (or cat, for that matter), and start
a getty on ttyUSB0 (or write into it any other way), everything is
totally fine.

I can observe the following problems when I start minicom on ttyUSB0:
- writing to ttyS0 using cat alone gives garbled output
- writing to ttyS0 using minicom always works
- running a getty on ttyS0 lets me log in once
- writing to ttyS0 using cat works fine while a working getty or minicom
  also has ttyS0 open
- running the getty on ttyS0 a second time gives me the same garbled
  output as cat gives me

The way that the output is garbled seems to be just missing characters,
in a mostly reproducible way. Repeatedly writing the string
abcdefghijklmnopqrstuvwxyz1234567890 into ttyS0 gives an output like
'akq7m3iy', where only every sixteenth character is shown, plus
an extra character in the second position.

	Arnd
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists