Re: Fedora 33 and perf probe failures

[Masami Hiramatsu <mhiramat@kernel.org>]

Hi Thomas,

On Wed, 18 Nov 2020 17:37:21 +0100
Thomas Richter <tmricht@linux.ibm.com> wrote:

> I debugged the failure of some perf test cases on Fedora 33. The following
> test cases fail on s390 and x86_64 using

Thanks for the report!
Let me setup Fedora33.

> 
> [root@f33 yum.repos.d]# uname -a
> Linux f33 5.9.8-200.fc33.x86_64 #1 SMP Tue Nov 10 21:58:19 UTC 2020
>                                 x86_64 x86_64 x86_64 GNU/Linux
> [root@f33 yum.repos.d]#
> 
> [root@f33 yum.repos.d]# perf test -F 74 77 78
> 74: Use vfs_getname probe to get syscall args filenames
>                 :Failed to write event: Invalid argument
> Error: Failed to add events.
> FAILED!
> 77: Check open filename arg using perf trace + vfs_getname
>                 :Failed to write event: Invalid argument
> Error: Failed to add events.
> FAILED!
> 78: Add vfs_getname probe to get syscall args filenames
>                 :Failed to write event: Invalid argument
> Error: Failed to add events.
> FAILED!
> [root@f33 yum.repos.d]#

BTW, do we have vfs_getname in the kernel?

> 
> The root cause is the output of perf probe -L which returns:
> [root@f33 yum.repos.d]# perf probe -L getname_flags
> Specified source line is not found.
> Error: Failed to show lines.

Hmm, could you run it with -vvv option?

> [root@f33 yum.repos.d]#
> 
> whereas on my Fedora 32 installation this command shows
> [root@t35lp46 perf]# cat /etc/redhat-release
> Fedora release 32 (Thirty Two)
> [root@t35lp46 perf]#
> 
> [root@t35lp46 perf]# ./perf probe -L getname_flags | tail -10
>      68                         return ERR_PTR(-ENOENT);
>                         }
>                 }
> 
>      72         result->uptr = filename;
>      73         result->aname = NULL;
>      74         audit_getname(result);
>                 return result;
> }
> 
> [root@t35lp46 perf]#
> 
> Any ideas how to fix this? Is this failure related to a missing debuginfod
> setup, even when I have installed the debuginfo packages for the kernel:

If you can find the vmlinux in debuginfo package, could you try
eu-addr2line to find getname_flags?
 
eu-addr2line -e /somewhere/to/vmlinux getname_flags+0

Thank you,

> 
> [root@f33 ~]# perf probe -L getname_flags
> Specified source line is not found.
>   Error: Failed to show lines.
> [root@f33 ~]# uname -a
> Linux f33 5.9.8-200.fc33.x86_64 #1 SMP Tue Nov 10 21:58:19 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
> [root@f33 ~]# rpm -qa | fgrep kernel | fgrep debuginfo
> kernel-debuginfo-common-x86_64-5.9.8-200.fc33.x86_64
> kernel-debuginfo-5.9.8-200.fc33.x86_64
> kernel-tools-debuginfo-5.9.7-200.fc33.x86_64
> [root@f33 ~]#
> ~                          
> 
> Thanks a lot
> -- 
> Thomas Richter, Dept 3252, IBM s390 Linux Development, Boeblingen, Germany
> --
> Vorsitzender des Aufsichtsrats: Gregor Pillen
> Geschäftsführung: Dirk Wittkopp
> Sitz der Gesellschaft: Böblingen / Registergericht: Amtsgericht Stuttgart, HRB 243294


-- 
Masami Hiramatsu <mhiramat@kernel.org>