resolving kernel addresses to symbol names via /proc/kallsyms
Milian Wolff
mail@milianw.de
Tue Jan 31 13:39:00 GMT 2017
Hey all,
should I be able to resolve kernel addresses to symbol names with elfutils
libdwfl? I did something like this:
m_dwfl = dwfl_begin(m_callbacks);
auto i_k = dwfl_linux_kernel_report_kernel(m_dwfl);
auto i_m = dwfl_linux_kernel_report_modules(m_dwfl);
Both i_k and i_m returned 0. Then, I picked a random address from my /proc/
kallsyms, e.g.:
ffffffff81001000 T hypercall_page
and try to find that symbol:
auto module = dwfl_addrmodule(m_dwfl, 0xffffffff81001000ll);
The module is non-null and points me at this module (comparing to output I get
from dwfl_getmodules):
0x61400000fa40 kernel ffffffff81000000
But when I try to get a symbol, I get a nullptr:
auto sym = dwfl_module_addrname(module, 0xffffffff81001000ll);
So, what am I missing?
Also, it doesn't seem to be possible to specify the path to the kallsyms file
with the current dwfl_linux_kernel_report_kernel API - how is this intended to
be handled? Should one instead use dwfl_linux_kernel_report_offline when one
wants to support cross-machine analysis?
Thanks
--
Milian Wolff
mail@milianw.de
http://milianw.de
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