Re: port-i386/40143 (Viewing an mpeg transport stream with mplayer causes crash)

[Andrew Doran <ad%NetBSD.org@localhost>]

The following reply was made to PR port-i386/40143; it has been noted by GNATS.

From: Andrew Doran <ad%NetBSD.org@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: 
Subject: Re: port-i386/40143 (Viewing an mpeg transport stream with mplayer 
causes crash)
Date: Fri, 20 Mar 2009 22:25:20 +0000

 The error recovery should be easy to solve for most interrupts and traps:
 disable interrupts until the prologue has assembled a frame, and only then
 re-enable interrupts. It can be done by converting existing trap gates into
 interrupt gates, and by sprinkling 'cli' where needed.
 
 A problem with this approach is call gates, which do not disable interrupts
 on entry. Call gates are used for IBCS and SVR4 system calls (and any other
 emulation, if you feel like it). For call gates one approach would be to
 have the trap handler clean up the mess.
 
 This does not solve the underlying problem, which is selectors becoming
 invalid while in kernel: assuming that mplayer is functioning correctly it
 should not happen. This is a seperate issue that also needs to be resolved.
 It appears to be caused by bugs with USER_LDT.