Re:

[Fredy Neeser <Fredy dot Neeser at solnet dot ch>]

Frank Ch. Eigler <fche <at> redhat.com> writes:

> 
> Fredy Neeser <Fredy.Neeser <at> solnet.ch> writes:
> 
> > I am trying to use systemtap (20070818 snapshot) on an IA32 Core Duo
> > system with Fedora Core 5 and a kernel which I built from vanilla
> > 2.6.18 sources.
> 
> Thank you for your high-quality problem report!
> 
> Other than dsmith's comment, there's another telltale problem:
> 
> > [...]
> > focused on module 'kernel = [0x100000-0x2bd504, bias 0x0] file
> > /boot/vmlinux-2.6.18-nfd1 ELF machine i?86 (code 3)
> > control symbols: kts: 0x0 kte: 0x0 stext: 0x0
> > parsed 'sys_open' -> func 'sys_open'
> > focused on module 'kernel = [0x100000-0x2bd504, bias 0x0] [...]
> 
> Before that second "focused" line, you should be seeing something like:
> 
> pattern 'sys_open' matches function 'sys_open'
> selected function sys_open
> probe sys_open <at> fs/open.c:977 kernel section=.text pc=0xc0471088
> 
> Can you do a smell test of your vmlinux file:
> 
> % ls -l /boot/vmlinux*
> % readelf -S /boot/vmlinux* | grep -i debug 
> 
> - FChE
> 
> 

Thanks!

Your reaction made me suspicious of having the wrong vmlinux file.
Bingo, we have two of them, one under directory
<my-kernel>/arch/i386/boot/compressed
and the other (the much larger one, i.e., the right one ...)
under just <my-kernel> ...

Great, SystemTap is working now for me :-)

The symptom mentioned by dsmith is gone and I see
"matches function 'sys_open'" as you said above.

Since it's quite easy to confuse the two vmlinux versions (unless
one looks at their sizes ...), an update in the README on how to
make systemtap aware of kernel debug info (for a hand-built kernel)
would probably be helpful.

Let me draft something that I can send you ...

Thanks again,
FN

PS: Just for the records, the wrong vmlinux gives

% ls -l arch/i386/boot/compressed/vmlinux
-rwxrwxr-x 1 fn fn 1798025 23. Jul 12:58 arch/i386/boot/compressed/vmlinux

% readelf -S arch/i386/boot/compressed/vmlinux | grep -i debug
  [ 7] .debug_aranges    PROGBITS    00000000 1b10bd 000020 00      0   0  1
  [ 8] .debug_pubnames   PROGBITS    00000000 1b10dd 000061 00      0   0  1
  [ 9] .debug_info       PROGBITS    00000000 1b113e 0019d2 00      0   0  1
  [10] .debug_abbrev     PROGBITS    00000000 1b2b10 000411 00      0   0  1
  [11] .debug_line       PROGBITS    00000000 1b2f21 0005d0 00      0   0  1
  [12] .debug_frame      PROGBITS    00000000 1b34f4 0001c4 00      0   0  4
  [13] .debug_str        PROGBITS    00000000 1b36b8 00041f 01  MS  0   0  1
  [14] .debug_loc        PROGBITS    00000000 1b3ad7 0022c0 00      0   0  1
  [15] .debug_ranges     PROGBITS    00000000 1b5d97 000680 00      0   0  1

while the right vmlinux gives
% ls -l vmlinux
-rwxrwxr-x 1 fn fn 42883188 23. Jul 12:23 vmlinux

% readelf -S vmlinux | grep -i debug
  [34] .debug_aranges    PROGBITS    00000000 37260d 008980 00      0   0  1
  [35] .debug_pubnames   PROGBITS    00000000 37af8d 02c222 00      0   0  1
  [36] .debug_info       PROGBITS    00000000 3a71af 1dc21c0 00      0   0  1
  [37] .debug_abbrev     PROGBITS    00000000 216936f 0f1d3c 00      0   0  1
  [38] .debug_line       PROGBITS    00000000 225b0ab 19a111 00      0   0  1
  [39] .debug_frame      PROGBITS    00000000 23f51bc 076c20 00      0   0  4
  [40] .debug_str        PROGBITS    00000000 246bddc 0c10d1 01  MS  0   0  1
  [41] .debug_loc        PROGBITS    00000000 252cead 244ea1 00      0   0  1
  [42] .debug_ranges     PROGBITS    00000000 2771d4e 062200 00      0   0  1