PR/42787 CVS commit: src/sys/arch/i386/i386

[Matthias Drochner <drochner%netbsd.org@localhost>]

The following reply was made to PR port-i386/42787; it has been noted by GNATS.

From: Matthias Drochner <drochner%netbsd.org@localhost>
To: gnats-bugs%gnats.NetBSD.org@localhost
Cc: 
Subject: PR/42787 CVS commit: src/sys/arch/i386/i386
Date: Sun, 14 Feb 2010 11:09:55 +0000

 Module Name:   src
 Committed By:  drochner
 Date:          Sun Feb 14 11:09:54 UTC 2010
 
 Modified Files:
        src/sys/arch/i386/i386: ibcs2_machdep.c svr4_machdep.c
 
 Log Message:
 fix confused CS selector, fixes the panic reported by Mark Davis
 per PR port-i386/42787 (the panic happens due to a GPF when a
 privileged descriptor is tried to be loaded with the UPL bit set)
 The original bug is very old (pre-2.0, i386/svr4_machdep.c rev. 1.69),
 but it was relatively harmless until the order of GDT entries was
 shuffled (pre-5.0, i386/segments.h rev. 1.42). Before, it caused
 a userlevel data selector to be used for CS which broke the emulation
 (likely the reason of PR port-i386/32424). The shuffle made that
 a privileged selector was used, causing the GPF.
 (recent -current doesn't panic on that GPF which seems to be a
 side effect of another change)
 
 
 To generate a diff of this commit:
 cvs rdiff -u -r1.39 -r1.40 src/sys/arch/i386/i386/ibcs2_machdep.c
 cvs rdiff -u -r1.95 -r1.96 src/sys/arch/i386/i386/svr4_machdep.c
 
 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.