Re: ERROR: Build-id mismatch: "kernel" vs. "vmlinux" byte 0 (0x00 vs 0x00)

["Frank Ch. Eigler" <fche at redhat dot com>]

Hi -


> >-14 is -EFAULT.  This should not happen unless our address
> >calculations have gotten messed up somehow.  Try rerunning stap with
> >-DDEBUG_TRANS -DDEBUG_SYMBOLS.

> Here are full logs with " stap --vp 9999 -DDEBUG_TRANS -DDEBUG_SYMBOLS"
> The working dropwatch:
> http://karl.hiramoto.org/temp/stap_dropwatch.txt
> The non working tcp_trace
> http://karl.hiramoto.org/temp/stap_tcp_trace.txt

Thanks.

The difference is that dropwatch uses tracepoints only, and does not
rely on kernel symbol/debug data.  That in turn means that stap does
not emit build-id-checking code.  A better test would be to vary
kernel version and/or systemtap version, but running with the same
script.  (Even a simple one like  probe kernel.function("sys_open"){}
should show the problem.)

I'm building myself a 2.6.34-rc3 kernel to see if something became
broken lately.


> there's also some errors like:
> [...]
> /tmp/stapEyVbEM/stapconf_6415a8d55b7118f55f4e4a8368ac8512_390.h
> /usr/share/systemtap/runtime/autoconf-grsecurity.c: In function foo:
> /usr/share/systemtap/runtime/autoconf-grsecurity.c:10: error: struct 
> module) has no member namedi~init_size_
> [...]

That's OK, runtime/autoconf-* bits are meant to detect kernel
characteristics by compilation success / failures.


- FChE