Date: Fri, 18 Aug 2017 17:11:15 +0000 (UTC) From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r322667 - head/sys/i386/i386 Message-ID: <201708181711.v7IHBFtO036108@repo.freebsd.org>
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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 <max@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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