[Bug dyninst/15061] New: stapdyn missing process.library.mark probe hits

[Bug dyninst/15061] New: stapdyn missing process.library.mark probe hits

[dsmith at redhat dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=15061

             Bug #: 15061
           Summary: stapdyn missing process.library.mark probe hits
           Product: systemtap
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: dyninst
        AssignedTo: systemtap@sourceware.org
        ReportedBy: dsmith@redhat.com
    Classification: Unclassified


While adding dyninst support to several testcases (commit 5acb534), I
investigated some odd failures with the systemtap.base/library.exp testcase. To
simplify things, let's avoid the testcase itself, but use its test programs.

(Note that the testcase has several failures with the linux runtime on modern
kernels, since there is no 'process.function.return' probe support yet.)

The following command should build the test programs - the vebose (-v) option
will cause the testcase to not clean up its test programs.

====
# cd testsuite
# make installcheck RUNTESTFLAGS="-v library.exp"
... stuff deleted ...
====

OK, now we've got the test programs (sdt_misc.x and libsdt.so).

With the linux runtime, we get the following:

====
# stap -e 'probe process("sdt_misc.x").library("libsdt.so").mark("*") {
printf("mark %s\n", $$name) }' -c ./sdt_misc.x
mark test_probe_2
mark test_probe_2
mark test_probe_0
mark test_probe_3
mark test_probe_4
mark test_probe_1
====

With the dyninst runtime, we get:

====
# stap --runtime=dyninst -e 'probe
process("sdt_misc.x").library("libsdt.so").mark("*") { printf("mark %s\n",
$$name) }' -c ./sdt_misc.x
mark test_probe_2
mark test_probe_1
====

So, the dyninst runtime missed 4 mark probe hits.

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[Bug dyninst/15061] stapdyn missing process.library.mark probe hits

[jistone at redhat dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=15061

Josh Stone <jistone at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |jistone at redhat dot com
         Resolution|                            |DUPLICATE

--- Comment #1 from Josh Stone <jistone at redhat dot com> 2013-01-24 17:20:37 UTC ---
I'm pretty sure this is because semaphores have been neglected, bug 14705.

*** This bug has been marked as a duplicate of bug 14705 ***

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[Bug dyninst/15061] stapdyn missing process.library.mark probe hits

[dsmith at redhat dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=15061

--- Comment #2 from David Smith <dsmith at redhat dot com> 2013-01-24 19:16:29 UTC ---
Looking at the source to libsdt.so (in testsuite/systemtap.base/sdt_misc.c), it
appears the problem is semaphores. Having two calls to 'test_probe_2', one
protected by a semaphore, one not protected, helped mislead me.

Sorry for the noise.

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