Re: [PATCH] n_tty: Protect minimum_to_wake reset for concurrent readers

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Mon, Nov 25, 2013 at 09:16:46AM -0800, Greg Kroah-Hartman wrote:
> On Mon, Nov 25, 2013 at 12:12:52PM -0500, Peter Hurley wrote:
> > On 11/25/2013 11:36 AM, Greg Kroah-Hartman wrote:
> > >On Thu, Nov 07, 2013 at 02:01:57PM -0500, Peter Hurley wrote:
> > >>With multiple, concurrent readers (each waiting to acquire the
> > >>atomic_read_lock mutex), a departing reader may mistakenly reset
> > >>minimum_to_wake after a new reader has already set a new value.
> > >>
> > >>Protect the minimum_to_wake reset with the atomic_read_lock critical
> > >>section.
> > >>
> > >>Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
> > >>---
> > >>  drivers/tty/n_tty.c | 4 ++--
> > >>  1 file changed, 2 insertions(+), 2 deletions(-)
> > >
> > >This patch doesn't apply to Linus's tree anymore (and hence, mine.)  Is
> > >it needed for 3.13-final?  Or just 3.14-rc1?  Either way, can you
> > >refresh it and resend?
> > 
> > Hmmm, for me this applies cleanly to your tty-linus branch:
> > 
> > peter@thor:~/src/kernels/tty$ git tree -10
> > * c7df628 (HEAD, tty-linus) n_tty: Protect minimum_to_wake reset for concurrent readers
> > * 3dcf344 (origin/tty-linus) TTY: amiserial, add missing platform check
> > * dc1dc2f TTY: pmac_zilog, check existence of ports in pmz_console_init()
> > * c284ee2 n_gsm: race between ld close and gsmtty open
> > * f301412 tty/serial/8250: fix typo in help text
> > * c77569d n_tty: Fix 4096-byte canonical reads
> > * 6f22253 n_tty: Fix echo overrun tail computation
> > * 42458f4 n_tty: Ensure reader restarts worker for next reader
> > * 6ce4eac (tag: v3.13-rc1, origin/tty-next, origin/master, origin/HEAD) Linux 3.13-rc1
> > 
> > I'll just resend it.
> 
> Oh nevermind, it has leading extra spaces, which something added, I'll
> go edit it by hand and fix it up, sorry for not noticing.

And 'git am' handles this just fine, I was just testing it out first
using 'patch' which didn't like the extra spaces, my fault.

sorry for the noise,

greg k-h