Re: [PATCH] n_tty: Protect minimum_to_wake reset for concurrentreaders

From: Greg Kroah-Hartman
Date: Mon Nov 25 2013 - 12:16:53 EST


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@xxxxxxxxxxxxxxxxxx>
> >>---
> >> 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.

greg k-h
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