registration error (rc -84) and -DSTP_OVERLOAD_THRESHOLD

[Daniel Migault]

Hi,

While running my tap script, I receive WARNINGs and would like to knwo 
how to consider them. Does it means that matching between source code 
and memory address presents dome differences? If so, is there any way to 
correct this mismatch ? How does it really impact the probe? For 
exmaple, does a probe on tcp_new_space for example don't consider the 
function ?

Pass 5: starting run.
WARNING: probe 
kernel.function("tcp_new_space@net/ipv4/tcp_input.c:4885") (address 
0xffffffff814064f0) registration error (rc -84)
WARNING: probe 
kernel.function("tcp_update_reordering@net/ipv4/tcp_input.c:935") 
(address 0xffffffff81404578) registration error (rc -84)
WARNING: probe 
kernel.function("tcp_should_expand_sndbuf@net/ipv4/tcp_input.c:4854") 
(address 0xffffffff814064f0) registration error (rc -84)
WARNING: probe 
kernel.function("ablkcipher_get_spot@crypto/ablkcipher.c:71") (address 
0xffffffff812059bc) registration error (rc -84)
[...]

By the way, I also noticed some problems with the 
-DSTP_OVERLOAD_THRESHOLD. The script does not run and sometime it may 
result by frezzing the OS. We don't have any problems with the 
-DSTP_NO_OVERLOAD option for example. I am using gcc version 4.6.0 
20110509 (Red Hat 4.6.0-7) (GCC).

stap -g --vp 00001 -DSTP_OVERLOAD_THRESHOLD script.stp

[root@fedora-amd64 systemtap.git]#
Pass 5: run failed.  Try again with another '--vp 00001' option.
[root@fedora-amd64 systemtap-script]#

Regards,

Daniel