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Re: semantic error: not accessible at this address
- From: David Smith <dsmith at redhat dot com>
- To: Vincent Bernat <bernat at luffy dot cx>
- Cc: systemtap at sourceware dot org
- Date: Fri, 27 Sep 2013 15:30:26 -0500
- Subject: Re: semantic error: not accessible at this address
- Authentication-results: sourceware.org; auth=none
- References: <87ioxmf2e9 dot fsf at guybrush dot luffy dot cx>
On 09/27/2013 03:14 PM, Vincent Bernat wrote:
> Hi!
>
> I have the following error when trying to use iotop example with a 3.11
> kernel:
>
> semantic error: not accessible at this address [man error::dwarf] (0xffffffff811b42b0, dieoffset: 0x177422e): identifier '$file' at /usr/share/systemtap/tapset/linux/vfs.stp:855:9
> source: file = $file
> ^
>
> Pass 2: analysis failed. [man error::pass2]
>
> I have read the wiki but if I use eu-readelf on vmlinux, I get the
> appropriate stuff:
>
> [1774208] subprogram
> external (flag) Yes
> name (strp) "vfs_write"
> decl_file (data1) 1
> decl_line (data2) 459
> prototyped (flag) Yes
> type (ref4) [17643bb]
> low_pc (addr) 0xffffffff811b42b0
> high_pc (addr) 0xffffffff811b44a9
> frame_base (data4) location list [5ec58b]
> sibling (ref4) [17744b9]
> [177422e] formal_parameter
> name (strp) "file"
> decl_file (data1) 1
> decl_line (data2) 459
> type (ref4) [1769ace]
> location (data4) location list [5ec5ff]
>
> The kernel was compiled with gcc 4.6.3 (the one in Ubuntu Precise). I
> have tried with gcc 4.7.3 instead but I get less complete information
> (the formal parameter lose its name).
>
> systemtap seems to use the right debug file:
>
> focused on module 'kernel' = [0xffffffff81000000-0xffffffff8240e000, bias 0
> file /usr/lib/debug/boot/vmlinux-3.11.0-7-generic ELF machine |x86_64 (code
> 62)
>
> How could I fix this?
This could certainly be a systemtap problem. To help narrow this down a
bit, could you show us the output of the following 2 commands?
# stap -V
# stap -L 'kernel.function("vfs_write").*'
--
David Smith
dsmith@redhat.com
Red Hat
http://www.redhat.com
256.217.0141 (direct)
256.837.0057 (fax)