Re: kern/47506

[Nick Hudson <skrll%netbsd.org@localhost>]

The following reply was made to PR kern/47506; it has been noted by GNATS.

From: Nick Hudson <skrll%netbsd.org@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: Quentin Garnier <cube%cubidou.net@localhost>, 
kern-bug-people%netbsd.org@localhost, 
 gnats-admin%netbsd.org@localhost, netbsd-bugs%netbsd.org@localhost, 
uwe%NetBSD.org@localhost
Subject: Re: kern/47506
Date: Fri, 02 May 2014 08:12:54 +0100

 On 05/02/14 05:35, Quentin Garnier wrote:
 > The following reply was made to PR kern/47506; it has been noted by GNATS.
 >
 > From: Quentin Garnier <cube%cubidou.net@localhost>
 > To: gnats-bugs%NetBSD.org@localhost
 > Cc: tech-net%netbsd.org@localhost
 > Subject: re: kern/47506
 > Date: Fri, 2 May 2014 03:16:43 +0000
 >
 >   Hi,
 >   
 >   It seems to me there is a race between tap_start() and tap_dev_poll().
 >   The splx() call in tap_dev_poll() needs to be moved after the call to
 >   selrecord().
 >   
 >   However, I'm not entirely certain how that interacts with the spin
 >   mutex that protects the selrecord() call.
 
 mutex(9) and spl(9) interact appropriately :)
 
 First  spin mutex_enter saves spl and last spin mutex_exit restores that 
 spl.
 
 Nick