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dtrace backtracing
- From: "Frank Ch. Eigler" <fche at redhat dot com>
- To: systemtap at sources dot redhat dot com
- Date: Sat, 11 Aug 2007 12:40:41 -0400
- Subject: dtrace backtracing
Hi -
FYI, piecing information together, it appears that both kernel- and
user-side backtrace functions in dtrace work by:
a) assuming that everything is compiled with frame pointers
b) assuming that the stack frames are not corrupted
c) walking the stack frame pointers to populate an array of PC value
for call sites
d) passing said array to dtrace userspace in the trace stream
e) dtrace userspace mapping the PC array to symbolic data later
by looking up ELF symbol tables
f) assuming that this deferred mapping is still valid
- FChE