strace stacktrace: offsets printed
Thomas De Schampheleire
patrickdepinguin at gmail.com
Tue Oct 28 14:28:17 UTC 2014
I'm glad that strace 4.9 has integrated the features previously part
of strace-plus. I successfully built and run it on a PowerPC linux
One thing I noticed: the function addresses printed are offset against
the virtual memory location of the text section, i.e. strace prints
0xdcc but this actually corresponds to 0x10000dcc.
When no symbolic information is available in the build (because it's
stripped), it would be nice that the addresses are in the second
format so that they can be matched directly with the contents of the
non-stripped ELF file (for example with the output of 'nm').
>From a comment in unwind.c (above the definition of
STACK_ENTRY_SYMBOL_FMT) I have the impression that this is by design,
but I wonder how usable this output is: how can one easily create a
symbolic stacktrace from it?
Not having symbolic information in applications is very typical in
embedded development. In this case, stacktraces taken from target only
have address information, and using fairly simple tools this
information can be matched against the output of nm to produce a
symbolic stacktrace, or sent to addr2line to get line number
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