• Mathieu Desnoyers's avatar
    Marker depmod fix core kernel list · 87f3b6b6
    Mathieu Desnoyers authored
    * Theodore Ts'o (tytso@mit.edu) wrote:
    >
    > I've been playing with adding some markers into ext4 to see if they
    > could be useful in solving some problems along with Systemtap.  It
    > appears, though, that as of 2.6.27-rc8, markers defined in code which is
    > compiled directly into the kernel (i.e., not as modules) don't show up
    > in Module.markers:
    >
    > kvm_trace_entryexit arch/x86/kvm/kvm-intel  %u %p %u %u %u %u %u %u
    > kvm_trace_handler arch/x86/kvm/kvm-intel  %u %p %u %u %u %u %u %u
    > kvm_trace_entryexit arch/x86/kvm/kvm-amd  %u %p %u %u %u %u %u %u
    > kvm_trace_handler arch/x86/kvm/kvm-amd  %u %p %u %u %u %u %u %u
    >
    > (Note the lack of any of the kernel_sched_* markers, and the markers I
    > added for ext4_* and jbd2_* are missing as wel.)
    >
    > Systemtap apparently depends on in-kernel trace_mark being recorded in
    > Module.markers, and apparently it's been claimed that it used to be
    > there.  Is this a bug in systemtap, or in how Module.markers is getting
    > built?   And is there a file that contains the equivalent information
    > for markers located in non-modules code?
    
    I think the problem comes from "markers: fix duplicate modpost entry"
    (commit d35cb360)
    
    Especially :
    
      -   add_marker(mod, marker, fmt);
      +   if (!mod->skip)
      +     add_marker(mod, marker, fmt);
        }
        return;
       fail:
    
    Here is a fix that should take care if this problem.
    
    Thanks for the bug report!
    Signed-off-by: default avatarMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
    Tested-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
    CC: Greg KH <greg@kroah.com>
    CC: David Smith <dsmith@redhat.com>
    CC: Roland McGrath <roland@redhat.com>
    CC: Sam Ravnborg <sam@ravnborg.org>
    CC: Wenji Huang <wenji.huang@oracle.com>
    CC: Takashi Nishiie <t-nishiie@np.css.fujitsu.com>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    87f3b6b6
modpost.c 54.2 KB