[Bug translator/31404] New: Systemtap unable to find kernel.trace("*") probe points on Fedora rawhide Linux 6.8 kernels

[Bug translator/31404] New: Systemtap unable to find kernel.trace("*") probe points on Fedora rawhide Linux 6.8 kernels

[wcohen at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=31404

            Bug ID: 31404
           Summary: Systemtap unable to find kernel.trace("*") probe
                    points on Fedora rawhide Linux 6.8 kernels
           Product: systemtap
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: translator
          Assignee: systemtap at sourceware dot org
          Reporter: wcohen at redhat dot com
  Target Milestone: ---

When reviewing the "make installcheck" results on Fedora rawhide.  I found that
a number of the tests using the tracepoint probe points were failing.  For
example:

Running
/home/wcohen/systemtap_write/systemtap/testsuite/systemtap.base/bz1027459.exp
...
spawn stap -wP
/home/wcohen/systemtap_write/systemtap/testsuite/systemtap.base/bz1027459.stp
semantic error: while resolving probe point: identifier 'kernel' at
/home/wcohen/systemtap_write/install/share/systemtap/tapset/linux/sysc_clone.stp:131:26
        source: probe tp_syscall.clone = kernel.trace("sys_enter")
                                         ^

semantic error: no match

Pass 2: analysis failed.  [man error::pass2]
Number of similar error messages suppressed: 2.
Rerun with -v to see them.
FAIL: bz1027459 -p5 (0)


The probe point can be seen with "perf list tracepoint", but doesn't show up
with systemtap:

[wcohen@rawhide systemtap]$ uname -a
Linux rawhide 6.8.0-0.rc5.41.fc41.x86_64 #1 SMP PREEMPT_DYNAMIC Mon Feb 19
14:05:40 UTC 2024 x86_64 GNU/Linux
[wcohen@rawhide systemtap]$ sudo perf list tracepoint |grep raw
[sudo] password for wcohen: 
  raw_syscalls:sys_enter                             [Tracepoint event]
  raw_syscalls:sys_exit                              [Tracepoint event]
[wcohen@rawhide systemtap]$ ../install/bin/stap  -L 'kernel.trace("sys_enter")'
[wcohen@rawhide systemtap]$ 

On Fedora 39 systemtap can find the tracepoints:

wcohen@fedora39:~/systemtap_write/systemtap$ uname -a
Linux fedora39 6.7.5-200.fc39.x86_64 #1 SMP PREEMPT_DYNAMIC Sat Feb 17 17:20:08
UTC 2024 x86_64 GNU/Linux
wcohen@fedora39:~/systemtap_write/systemtap$ sudo perf list tracepoint |grep
raw
  raw_syscalls:sys_enter                             [Tracepoint event]
  raw_syscalls:sys_exit                              [Tracepoint event]
wcohen@fedora39:~/systemtap_write/systemtap$ ../install/bin/stap  -L
'kernel.trace("sys_enter")'
kernel.trace("raw_syscalls:sys_enter") $regs:struct pt_regs* $id:long int

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[Bug translator/31404] Systemtap unable to find kernel.trace("*") probe points on Fedora rawhide Linux 6.8 kernels

[wcohen at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=31404

William Cohen <wcohen at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED

--- Comment #1 from William Cohen <wcohen at redhat dot com> ---
Was able to compare the tracequery_kmod_1 builds between fedora 39 and rawhide.
 The problem on rawhide is that the additional -Werror-missing-prototypes
option is being passed into rawhide build which causes:

$  ../install/bin/stap  --disable-cache -k -vvvvv -L
'kernel.trace("sys_enter")' >& rawhide_log
have /tmp/stapypAUhu
make -C /lib/modules/$(uname -r)/build M=/tmp/stapypAUhu/tracequery_kmod_1
modules
 make -C /lib/modules/$(uname -r)/build M=/tmp/stapypAUhu/tracequery_kmod_1
modules
make: Entering directory
'/usr/src/kernels/6.8.0-0.rc5.20240222git39133352cbed.44.fc41.x86_64'
  CC [M]  /tmp/stapypAUhu/tracequery_kmod_1/tracequery_kmod_1_2.o
/tmp/stapypAUhu/tracequery_kmod_1/tracequery_kmod_1_2.c:51:8: error: no
previous prototype for ‘stapprobe_read_msr’ [-Werror=missing-prototypes]
   51 |   void stapprobe_##name(proto) {}
      |        ^~~~~~~~~~
./include/linux/tracepoint.h:555:9: note: in expansion of macro ‘DECLARE_TRACE’
  555 |         DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
      |         ^~~~~~~~~~~~~
./arch/x86/include/asm/msr-trace.h:40:1: note: in expansion of macro
‘DEFINE_EVENT’
   40 | DEFINE_EVENT(msr_trace_class, read_msr,
      | ^~~~~~~~~~~~
/tmp/stapypAUhu/tracequery_kmod_1/tracequery_kmod_1_2.c:51:8: error: no
previous prototype for ‘stapprobe_write_msr’ [-Werror=missing-prototypes]
   51 |   void stapprobe_##name(proto) {}
      |        ^~~~~~~~~~
./include/linux/tracepoint.h:555:9: note: in expansion of macro ‘DECLARE_TRACE’
  555 |         DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
      |         ^~~~~~~~~~~~~
./arch/x86/include/asm/msr-trace.h:45:1: note: in expansion of macro
‘DEFINE_EVENT’
   45 | DEFINE_EVENT(msr_trace_class, write_msr,
      | ^~~~~~~~~~~~
/tmp/stapypAUhu/tracequery_kmod_1/tracequery_kmod_1_2.c:51:8: error: no
previous prototype for ‘stapprobe_rdpmc’ [-Werror=missing-prototypes]
   51 |   void stapprobe_##name(proto) {}
      |        ^~~~~~~~~~
./include/linux/tracepoint.h:555:9: note: in expansion of macro ‘DECLARE_TRACE’
  555 |         DECLARE_TRACE(name, PARAMS(proto), PARAMS(args))
      |         ^~~~~~~~~~~~~
./arch/x86/include/asm/msr-trace.h:50:1: note: in expansion of macro
‘DEFINE_EVENT’
   50 | DEFINE_EVENT(msr_trace_class, rdpmc,
      | ^~~~~~~~~~~~
cc1: all warnings being treated as errors
make[2]: *** [scripts/Makefile.build:243:
/tmp/stapypAUhu/tracequery_kmod_1/tracequery_kmod_1_2.o] Error 1
make[1]: ***
[/usr/src/kernels/6.8.0-0.rc5.20240222git39133352cbed.44.fc41.x86_64/Makefile:1939:
/tmp/stapypAUhu/tracequery_kmod_1] Error 2
make: *** [Makefile:252: __sub-make] Error 2
make: Leaving directory
'/usr/src/kernels/6.8.0-0.rc5.20240222git39133352cbed.44.fc41.x86_64'

There looks to be a couple ways to fix this.

1) kernel git commit 1c57b9f63ab34f01b8c73731cc0efacb5a9a2f16 adds a "static"
before the function definition.

2) kernel git commit c97dac57c804b53eab492ca0230d86356729d633 adds following
line to Kbuild to remove the -Wmissing-prototypes:

+KBUILD_CFLAGS := $(filter-out -Wmissing-prototypes -Wmissing-declarations,
$(KBUILD_CFLAGS))
+

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[Bug translator/31404] Systemtap unable to find kernel.trace("*") probe points on Fedora rawhide Linux 6.8 kernels

[wcohen at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=31404

William Cohen <wcohen at redhat dot com> changed:

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

--- Comment #2 from William Cohen <wcohen at redhat dot com> ---
This issue has been fixed with the following commit:

commit 7765366ae09859cf68d55782185ec3ceb9a04ed5 (HEAD -> master, origin/master,
origin/HEAD)
Author: William Cohen <wcohen@redhat.com>
Date:   Wed Feb 28 10:43:51 2024 -0500

    PR31404: Make tracepoint queries work with gcc14

    The Fedora rawhide Linux 6.8 kernels are built with gcc14 and include
    -Wmissing-prototypes in the CFLAGS options.  When building the
    kernel modules to query the available tracepoints errors occur
    resulting in kernel tracepoints being found. The fix is to
    include a function declaration before the function definition
    in the DECLARE_TRACE macro.

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