Author: avg
Date: Tue Apr 12 06:46:54 2016
New Revision: 297846
URL: https://svnweb.freebsd.org/changeset/base/297846

Log:
  [amd64] dtrace_invop handler is to be called only for kernel exceptions
  
  DTrace-related exceptions in userland code are handled elsewhere.
  One practical problem was a crash in dtrace_invop_start() when saved
  %rsp pointed to a virtual address that was not backed.
  
  i386 code already ignored userland exceptions.
  
  Reviewed by: markj, kib
  MFC after:    2 weeks
  Differential Revision: https://reviews.freebsd.org/D5906

Modified:
  head/sys/amd64/amd64/exception.S

Modified: head/sys/amd64/amd64/exception.S
==============================================================================
--- head/sys/amd64/amd64/exception.S    Tue Apr 12 03:55:33 2016        
(r297845)
+++ head/sys/amd64/amd64/exception.S    Tue Apr 12 06:46:54 2016        
(r297846)
@@ -211,6 +211,8 @@ alltraps_pushregs_no_rdi:
         * interrupt. For all other trap types, just handle them in
         * the usual way.
         */
+       testb   $SEL_RPL_MASK,TF_CS(%rsp) /* Did we come from kernel? */
+       jnz     calltrap                /* ignore userland traps */
        cmpl    $T_BPTFLT,TF_TRAPNO(%rsp)
        jne     calltrap
 
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