Re: kern/41225: sys_mqueue.c mq->mq_notify_proc can disappear

[David Laight <david%l8s.co.uk@localhost>]

The following reply was made to PR kern/41225; it has been noted by GNATS.

From: David Laight <david%l8s.co.uk@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: 
Subject: Re: kern/41225: sys_mqueue.c mq->mq_notify_proc can disappear
Date: Thu, 16 Apr 2009 07:38:23 +0100

 On Wed, Apr 15, 2009 at 10:10:01PM +0000, ad%netbsd.org@localhost wrote:
 > >Synopsis:       sys_mqueue.c mq->mq_notify_proc can disappear
 > 
 > Quick and dirty fix:
 > 
 > Change mq_notify() to store a pid_t and use p_find() when sending
 > signals. mqueue can send signals to unrelated processes after
 > the proc exits.
 
 Can the message queue hold a reference count againt the proc table slot ?
 This would stop the slot being reused.
 
 I guess it should also be possibly to determine that the process had died
 when it tries to send a new signal - removing the need for the exithook.
 
 Just don't do the fubar recently added to linux where kernel code
 can no longer send a signal to a pid!
 
        David
 
 -- 
 David Laight: david%l8s.co.uk@localhost