lkml.org 
[lkml]   [2015]   [Feb]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
Subjectperf kernel module symbols
From
Hello,

I’m having some trouble getting perf to load symbols for my kernel
module. If I do a system wide capture for example with “perf record -g
fp -a sleep 15” followed by “perf report | head” it tells me the
following:

No kallsyms or vmlinux with build-id
3b4704f9bcec1645cd1041286dd5125af061ca95 was found
[mymodule] with build id 3b4704f9bcec1645cd1041286dd5125af061ca95 not
found, continuing without symbols

The module does show up in the list when I do “perf buildid-list”,
however it is not present in “~/.debug/.build-id”. I tried to manually
add it with “perf buildid-cache -a /lib/modules/`uname
-r`/extra/mymodule”. However then when I do “perf report” I get a
Segmentation fault.

I did manage to partly work-around the issue by typing “perf report
–symfs=/”. I still get the error “build id not found, continuing
without symbols” but the symbols do get resolved correctly as I can
see function names rather than just hex addresses in the report. But I
still cannot annotate functions, I get the following error:

objdump: '[mymodule]': No such file

If I statically link my driver into the kernel instead of using
modules then everything works fine, however I’d rather not do this. I
am using perf version 3.10.40-ltsi. Any help regarding this issue
would be greatly appreciated.

Regards,

Martin.


\
 
 \ /
  Last update: 2015-02-18 15:41    [W:0.050 / U:0.276 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site