linux-kernel - Re: [PATCH] tty: Add driver unthrottle in ioctl(...,TCFLSH,..).

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]

Message-ID: <50AD4A01.7060500@ilyx.ru>
Date:	Thu, 22 Nov 2012 01:39:13 +0400
From:	Ilya Zykov <ilya@...x.ru>
To:	Alan Cox <alan@...rguk.ukuu.org.uk>
CC:	linux-kernel@...r.kernel.org,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Andrew McGregor <andrew.mcgregor@...iedtelesis.co.nz>
Subject: Re: [PATCH] tty: Add driver unthrottle in ioctl(...,TCFLSH,..).

On 22.11.2012 1:30, Alan Cox wrote:
>> Function reset_buffer_flags() also invoked during the
>> ioctl(...,TCFLSH,..). At the time of request we can have full buffers
>> and throttled driver too. If we don't unthrottle driver, we can get
>> forever throttled driver, because after request, we will have
>> empty buffers and throttled driver and there is no place to unthrottle driver.
>> It simple reproduce with "pty" pair then one side sleep on tty->write_wait,
>> and other side do ioctl(...,TCFLSH,..). Then there is no place to do writers wake up.
>
>
> So instead of revertng it why not just fix it ? Just add an argument to
> the reset_buffer_flags function to indicate if unthrottling is permitted.
>
> Alan
>
Because in my opinion, unthrottling permitted always, except release 
last filp (tty->count == 0)

--
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/