[Bug runtime/10601] New: user-space deref/registers in loc2c

[Bug runtime/10601] New: user-space deref/registers in loc2c

[fche at redhat dot com]

For secure/robust memory and register access for user-space $target expressions,
the translator must parametrize loc2c to emit different calls for user-space
probes than for kernel-space ones.  This is partly so that user-space $pointers
can't poke at kernel memories, and vice versa.

Related, the user-space register/memory access logic must become aware of
32-bit vs. 64-bit user-space processes on a 64-bit host.  For registers,
this appears to require use of the proper utrace regset machinery instead
of poking at pt_regs.

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           Summary: user-space deref/registers in loc2c
           Product: systemtap
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: runtime
        AssignedTo: systemtap at sources dot redhat dot com
        ReportedBy: fche at redhat dot com


http://sourceware.org/bugzilla/show_bug.cgi?id=10601

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[Bug runtime/10601] user-space deref/registers in loc2c

[jistone at redhat dot com]

------- Additional Comments From jistone at redhat dot com  2009-09-03 21:11 -------
Likewise, @cast will need to learn whether its type should be treated as a user
or kernel.  This can't come from probe context, since @cast can appear in any
probe or function.

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                 CC|                            |jistone at redhat dot com


http://sourceware.org/bugzilla/show_bug.cgi?id=10601

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[Bug runtime/10601] user-space deref/registers in loc2c

[mjw at redhat dot com]

------- Additional Comments From mjw at redhat dot com  2009-09-04 07:05 -------
This is the root cause of bug #10318 "Bad address reading arg from mark probe"
which also contains some discussions about the implementation of this in loc2c.
The register mapping disparity also seems to be the root cause of some of the
exelib.exp mark.tcl tests failing (currently disabled) on 32-on-64 bit systems,
bug #10289 "stap probes user space markers don't work with 32-on-64
executables". On i386 some sdt_misc.exp sdt_types tests are failing, which most
likely can also be attributed to the register fetch mismatch in user space.

It might be good to make comment #1 into its own bug.

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           What    |Removed                     |Added
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OtherBugsDependingO|                            |10289, 10318
              nThis|                            |
         AssignedTo|systemtap at sources dot    |mjw at redhat dot com
                   |redhat dot com              |
             Status|NEW                         |ASSIGNED


http://sourceware.org/bugzilla/show_bug.cgi?id=10601

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[Bug runtime/10601] user-space deref/registers in loc2c

[fche at redhat dot com]

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           What    |Removed                     |Added
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OtherBugsDependingO|                            |10907
              nThis|                            |


http://sourceware.org/bugzilla/show_bug.cgi?id=10601

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