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02-09-2006 meeting minutes
- From: Hien Nguyen <hien at us dot ibm dot com>
- To: SystemTAP <systemtap at sources dot redhat dot com>
- Date: Thu, 09 Feb 2006 15:58:20 -0800
- Subject: 02-09-2006 meeting minutes
Attendees
IBM - Jim, Hien, Vara, Richard, Prasanna, Maneesh, Ananth
Redhat - Will, Martin, Frank
Intel - Anil, Josh
Hitachi - Satoshi
LKML watch -
Redhat is next to watch LKML. Hien will post summary.
elfutils -
No new news. Elena is on PTO.
User space probes -
Jim suggested to stay with Prasanna's approach since there is too much
objection on the mailing list. Prassana had posted take2 of the user
probes patches.
Richard indicated that we should not allow interrupt during single step
out of line or inline (for stack base architecture). Try to disable
interrupt just for a small window (as small as possible) when single step.
kprobes fault handler -
Prasanna will work on the patch. Anil would like to include this patch
in the RHEL4 U4 back port set.
We need to delay the kprobe notification registering until some one
register a probes (other than the inital trampoline probe). We may need
to consider a way to unregister kprobes notification ....
The discussion moved to disable kprobe completely (not even compiled in)
when CONFIG_MODULEs= disable
kprobe vs debugger -
The general consensus in the group is to not allow inserting probe if
other apps already put a breakpoint at that same location. Propose a
change to ptrace to do the same (not allow setting breakpoint if someone
else already did). Unpredictable results will happen sometime, but it is
not terribly bad (document what would happen and why)
Prasanna will work on this and roll them into the future user probe patches.
kprobe test-
Test cases for all bug fixes should be checked in to CVS tests/kernel by
the end of Feb.
4g/4g -
Satoshi indicated that Redhat supports 4g/4g kernel, what about
kprobes/ user probes. Kprobe/user space probe does not support 4g/4g is
an option, but there are customers currently using it.
We need to understand what are the issues. Perhaps the 4g/4g people
should look at our current kprobe/user probes implementation and give us
their opinions.
Ananth said 4g/4g is not in the mainline, therefore it will be harder
to user probes support 4g/4g to go to the mainline.
kprobe-booster -
Satoshi announced that kprobe-booster is now in the mm tree. according
to Satoshi, there will a port for x86_64 and ia64. What's about ppc64?