Re: [gentoo-user] SystemTap failing on basic check

[Fernando Rodriguez <frodriguez.developer@outlook.com>]

On Monday, September 21, 2015 7:15:59 AM Lukáš Oliva wrote:
>   Hi,
> I am trying SystemTap - a tool for dynamic tracing on Gentoo and I have
> some troubles to make it working. I followed the guide on
> 
> https://sourceware.org/systemtap/wiki/SystemTapWithSelfBuiltKernel
> 
> and built the kernel with required options:
> 
> zgrep -E
> 'CONFIG_DEBUG_INFO|CONFIG_KPROBES|CONFIG_RELAY|CONFIG_DEBUG_FS|
CONFIG_MODULES|CONFIG_MODULE_UNLOAD|CONFIG_UPROBES|CONFIG_DEBUG_INFO'
> /proc/config.gz
> CONFIG_RELAY=y
> CONFIG_KPROBES=y
> CONFIG_UPROBES=y
> CONFIG_MODULES_USE_ELF_RELA=y
> CONFIG_MODULES=y
> CONFIG_MODULE_UNLOAD=y
> CONFIG_DEBUG_INFO=y
> # CONFIG_DEBUG_INFO_REDUCED is not set
> # CONFIG_DEBUG_INFO_SPLIT is not set
> CONFIG_DEBUG_INFO_DWARF4=y
> CONFIG_DEBUG_FS=y
> # CONFIG_KPROBES_SANITY_TEST is not set
> 
> But even the simplest check fails on:
> 
> stap -r /usr/src/linux -v -e 'probe vfs.read {printf("read performed\n");
> exit()}'
> Pass 1: parsed user script and 122 library script(s) using
> 214692virt/125980res/5604shr/122476data kb, in 450usr/20sys/464real ms.
> Pass 2: analyzed script: 1 probe(s), 1 function(s), 3 embed(s), 0 global(s)
> using 347656virt/260520res/6984shr/255440data kb, in
> 1210usr/250sys/1462real ms.
> Pass 3: translated to C into
> "/tmp/stap2nY7sY/stap_9aad5fb97c53bb7c4bc51dce0ccbb236_1259_src.c" using
> 347656virt/260772res/7236shr/255440data kb, in 0usr/0sys/4real ms.
> In file included from /usr/share/systemtap/runtime/linux/task_finder.c:17:0,
>                  from /usr/share/systemtap/runtime/linux/runtime.h:206,
>                  from /usr/share/systemtap/runtime/runtime.h:24,
>                  from
> /tmp/stap2nY7sY/stap_9aad5fb97c53bb7c4bc51dce0ccbb236_1259_src.c:24:
> /usr/share/systemtap/runtime/linux/task_finder2.c: In function
> '__stp_call_mmap_callbacks_with_addr':
> /usr/share/systemtap/runtime/linux/task_finder2.c:695:24: error: 'struct
> file' has no member named 'f_dentry'
>    dentry = vma->vm_file->f_dentry;
>                         ^
> /usr/share/systemtap/runtime/linux/task_finder2.c: In function
> '__stp_call_mmap_callbacks_for_task':
> /usr/share/systemtap/runtime/linux/task_finder2.c:1198:42: error: 'struct
> file' has no member named 'f_dentry'
>         vma_cache_p->dentry = vma->vm_file->f_dentry;
>                                           ^
> scripts/Makefile.build:258: recipe for target
> '/tmp/stap2nY7sY/stap_9aad5fb97c53bb7c4bc51dce0ccbb236_1259_src.o' failed
> make[1]: ***
> [/tmp/stap2nY7sY/stap_9aad5fb97c53bb7c4bc51dce0ccbb236_1259_src.o] Error 1
> Makefile:1390: recipe for target '_module_/tmp/stap2nY7sY' failed
> make: *** [_module_/tmp/stap2nY7sY] Error 2
> WARNING: kbuild exited with status: 2
> Pass 4: compiled C into "stap_9aad5fb97c53bb7c4bc51dce0ccbb236_1259.ko" in
> 3230usr/260sys/4290real ms.
> Pass 4: compilation failed.  [man error::pass4]
> 
> I am wondering now - is there anything wrong with my aproach? Does anyone
> succesfully use SystemTap on Gentoo? And if so, could you help me to make
> this running?
> 
>   Lukas

It is outdated. It's trying to build a module that was written for an old 
kernel. I remember that change because it broke some module for me, I think it 
was on kernel 3.12.x or 3.14.x

-- 
Fernando Rodriguez