Author: kib
Date: Fri Aug 18 17:11:15 2017
New Revision: 322667
URL: https://svnweb.freebsd.org/changeset/base/322667
Log:
When checking that #UD comes from kernel mode, check that the
exception did not happen in vm86 mode. A vm86 userland process could
have a %cs that matches GSEL_KPL, while dtrace cannot hook it.
Submitted by: Maxime Villard <m...@m00nbsd.net>
MFC after: 3 days
Modified:
head/sys/i386/i386/exception.s
Modified: head/sys/i386/i386/exception.s
==============================================================================
--- head/sys/i386/i386/exception.s Fri Aug 18 16:43:59 2017
(r322666)
+++ head/sys/i386/i386/exception.s Fri Aug 18 17:11:15 2017
(r322667)
@@ -187,11 +187,14 @@ IDTVEC(ill)
cmpl $0,dtrace_invop_jump_addr
je norm_ill
- /* Check if this is a user fault. */
- cmpl $GSEL_KPL, 4(%esp) /* Check the code segment. */
-
- /* If so, just handle it as a normal trap. */
+ /*
+ * Check if this is a user fault. If so, just handle it as a normal
+ * trap.
+ */
+ cmpl $GSEL_KPL, 4(%esp) /* Check the code segment */
jne norm_ill
+ testl $PSL_VM, 8(%esp) /* and vm86 mode. */
+ jnz norm_ill
/*
* This is a kernel instruction fault that might have been caused
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