[Bug runtime/10381] New: sdt.h macros create relocatable addresses in non-writable allocated .probes section

[Bug runtime/10381] New: sdt.h macros create relocatable addresses in non-writable allocated .probes section

[mjw at redhat dot com]

This causes selinux memory protection failures:

SELinux is preventing uprobesgcc-O0de from loading
/usr/local/build/systemtap-obj/testsuite/libuprobeslibgcc-O0default-debug.so
which requires text relocation.

Which look like:

./myexe: error while loading shared libraries: libmylib.so: cannot open shared
object file: No such file or directory

Where mylib.c just has the innocent looking:

STAP_PROBE1(test, lib_main, 1);

This seems to be caused by the fact that we are taking the address of the
generated label (&&label) and store that in the .probes section. Which seem to
result in R_X86_64_RELATIVE relocations in the .probes section, which is
insegment 0 which is LOADed with just R E, not W.

-- 
           Summary: sdt.h macros create relocatable addresses in non-
                    writable allocated .probes section
           Product: systemtap
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: runtime
        AssignedTo: systemtap at sources dot redhat dot com
        ReportedBy: mjw at redhat dot com


http://sourceware.org/bugzilla/show_bug.cgi?id=10381

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[Bug runtime/10381] sdt.h macros create relocatable addresses in non-writable allocated .probes section

[mjw at redhat dot com]

------- Additional Comments From mjw at redhat dot com  2009-07-10 11:56 -------
commit 880fc23fa180ae9c9557e7ff945f5f1e750aef15
Author: Mark Wielaard <mjw@redhat.com>
Date:   Fri Jul 10 13:53:00 2009 +0200

    PR10381 sdt.h macros create relocatable addresses in non-writable section.
    
    Allocated section needs to be writable when creating pic shared objects
    because we store relocatable addresses in them.
    
    * includes/sys/sdt.h (ALLOCSEC): New macro, depends on __PIC__.
      (STAP_PROBE_DATA_): Use new ALLOCSEC macro.


-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED


http://sourceware.org/bugzilla/show_bug.cgi?id=10381

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