Messages in this thread | | | Subject | Re: [RFC PATCH 2/8] perf probe powerpc: Fix symbol fixup issues due to ELF type | From | Michael Ellerman <> | Date | Wed, 10 Dec 2014 20:50:50 +1100 |
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On Tue, 2014-12-09 at 23:04 +0530, Naveen N. Rao wrote: > If using the symbol table, symbol addresses are not being fixed up > properly, resulting in probes being placed at wrong addresses: > > # perf probe do_fork > Added new event: > probe:do_fork (on do_fork) > > You can now use it in all perf tools, such as: > > perf record -e probe:do_fork -aR sleep 1 > > # cat /sys/kernel/debug/tracing/kprobe_events > p:probe/do_fork _text+635952 > # printf "%x" 635952 > 9b430 > # grep do_fork /boot/System.map > c0000000000ab430 T .do_fork
OK, but why is that happening? And why does checking for ET_DYN fix it?
> Fix by checking for ELF type ET_DYN used by ppc64 kernels.
We sometimes produce ET_DYN kernels, but only if CONFIG_RELOCATABLE=y.
cheers
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