[Bug runtime/30123] New: bitfield.exp fails with fresh kernels

[Bug runtime/30123] New: bitfield.exp fails with fresh kernels

[mcermak at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=30123

            Bug ID: 30123
           Summary: bitfield.exp fails with fresh kernels
           Product: systemtap
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: runtime
          Assignee: systemtap at sourceware dot org
          Reporter: mcermak at redhat dot com
  Target Milestone: ---

With Rawhide or recent RHEL9, the bitfield.exp testcase fails.  The problem
seems to be with @cast().  To demonstrate it, let's have the following code
snippet:

=======8<=======
%{
#include <linux/tcp.h>
static struct tcphdr foo = {0};
%}

function get_ptr:long() %{ STAP_RETVALUE = (long)&foo; /* pure */ %}


probe begin {
    ptr = get_ptr()

    # setter1 (seems to work)
    %{ foo.ack = 1 %}

    # setter2 (doesn't seem to work)
    # @cast(ptr, "tcphdr", "kernel<linux/tcp.h>")->ack = 1

    # printer1 (seems to work)
    println(%{ foo.ack %})

    # printer2 (doesn't seem to work)
    println(@cast(ptr, "tcphdr", "kernel<linux/tcp.h>")->ack)

    exit()
}
=======8<=======

A success is to write 1 to foo->ack and then read/print it.  When embedded C is
used, things work fine.  Using @cast() however, the experiment fails both to
write the data, and to read it.  Tested with 6.2.0-0.rc8.57.fc39 and
5.14.0-252.el9.

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[Bug runtime/30123] bitfield.exp fails with fresh kernels

[wcohen at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=30123

William Cohen <wcohen at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |wcohen at redhat dot com

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[Bug runtime/30123] bitfield.exp fails with fresh kernels

[fche at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=30123

Frank Ch. Eigler <fche at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Depends on|                            |29037
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED
                 CC|                            |fche at redhat dot com

--- Comment #1 from Frank Ch. Eigler <fche at redhat dot com> ---
commit aeb35e508eaa completes the work begun back in bug #29037.


Referenced Bugs:

https://sourceware.org/bugzilla/show_bug.cgi?id=29037
[Bug 29037] Systemtap unable to find struct bitfield members for gcc11 compiled
code
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