Re: lib/25563

[David Holland <dholland-bugs%netbsd.org@localhost>]

The following reply was made to PR lib/25563; it has been noted by GNATS.

From: David Holland <dholland-bugs%netbsd.org@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: 
Subject: Re: lib/25563
Date: Sun, 29 Mar 2009 00:39:11 +0000

 On Sat, Mar 28, 2009 at 08:45:01PM +0000, Andrew Doran wrote:
  > From: Andrew Doran <ad%netbsd.org@localhost>
  > To: gnats-bugs%NetBSD.org@localhost
  > Cc: 
  > Subject: Re: lib/25563
  > Date: Sat, 28 Mar 2009 20:43:58 +0000
  > 
  >  On Sat, Mar 28, 2009 at 03:30:04AM +0000, David Holland wrote:
  >  
  >>  What's supposed to happen if you use sigaltstack in a multithreaded
  >>  program anyway? Is the alternate stack supposed to be per-thread?
  >  
  >  Pretty much everything about signals is per-thread except for the signal
  >  disposition and job control.
 
 In that case, probably the right answer for the time being is to set
 an interval tree (or some such) that maps from stack ranges to
 threads. It won't be very fast, but it'll work... and will allow
 supporting different-sized thread stacks.
 
 Or we could have the pthreads sigaltstack reject any stack that isn't
 exactly SIGSTKSZ, and have SIGSTKSZ be the pthread stack size, and
 then one line of code in pthread__self or so would make it all work.
 
 
 Hrm, I wonder if PIE can be abused to provide TLS...
 
 -- 
 David A. Holland
 dholland%netbsd.org@localhost