[Bug kprobes/10991] New: freeze on x86_64 for most scripts

[Bug kprobes/10991] New: freeze on x86_64 for most scripts

[sphink at gmail dot com]

I am running a preemptive x86_64 kernel (pretty much just the CentOS 5.3 kernel
with preemption enabled). Most systemtap scripts hang the machine. I have also
tried running it from within a VirtualBox VM, and get similar results.

The version I am using on actual hardware and in the VM is
systemtap-0.9.7-5.el5. Within the VM, I have also compiled the snapshot from
20091114. It managed to run for a little while before hanging.

Specific example: this script

probe kernel.function("*@net/socket.c")
{
  printf ("%s -> %s\n", thread_indent(1), probefunc())
}
probe kernel.function("*@net/socket.c").return
{
  printf ("%s <- %s\n", thread_indent(-1), probefunc())
}

run as stap -v socket-tree.stap

On the hardware, it just hangs immediately after it starts running. On the VM,
it does the same for 0.9.7, but with the snapshot version it manages to print
out (after "Pass 5: starting run."):

   0 ntpd(1903): -> do_sock_read
1000834 ntpd(1902): <- do_sock_read

and then hangs the VM. The same thing on my 32-bit desktop prints out a bunch of
stuff and then exits cleanly after 1.2 seconds. (Without me pressing Ctrl-C,
which I don't understand yet, but that's different.)

Earlier, I also got an oops on the VM with 0.9.7, but I can't remember what
exactly I was doing. (It was something simple like stap -v -e 'probe syscall.* {
printf("I am alive\n"); exit(); }')

I can post my .config. I didn't change a whole lot in it. It is not built to be
relocatable.

-- 
           Summary: freeze on x86_64 for most scripts
           Product: systemtap
           Version: unspecified
            Status: NEW
          Severity: critical
          Priority: P2
         Component: kprobes
        AssignedTo: systemtap at sources dot redhat dot com
        ReportedBy: sphink at gmail dot com


http://sourceware.org/bugzilla/show_bug.cgi?id=10991

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[Bug kprobes/10991] freeze on x86_64 for most scripts

[sphink at gmail dot com]

------- Additional Comments From sphink at gmail dot com  2009-11-20 01:45 -------
Actually, it's kind of random how far the VM makes it. I rebooted and ran the
same thing, and this time only the 1st line made it out.


-- 


http://sourceware.org/bugzilla/show_bug.cgi?id=10991

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[Bug kprobes/10991] freeze on centos5.3+preempt x86_64 for most scripts

[fche at redhat dot com]

------- Additional Comments From fche at redhat dot com  2009-11-20 02:05 -------
I suspect we need to get hold of a suchly configured kernel
in order to diagnose the situation.


-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|freeze on x86_64 for most   |freeze on centos5.3+preempt
                   |scripts                     |x86_64 for most scripts


http://sourceware.org/bugzilla/show_bug.cgi?id=10991

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[Bug kprobes/10991] freeze on centos5.3+preempt x86_64 for most scripts

[mhiramat at redhat dot com]

------- Additional Comments From mhiramat at redhat dot com  2009-11-20 20:21 -------
(In reply to comment #0)
> I am running a preemptive x86_64 kernel (pretty much just the CentOS 5.3 kernel
> with preemption enabled).

Does this happen on upstream kernel too? (with preemption enabled)


-- 


http://sourceware.org/bugzilla/show_bug.cgi?id=10991

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[Bug kprobes/10991] freeze on centos5.3+preempt x86_64 for most scripts

[sphink at gmail dot com]

------- Additional Comments From sphink at gmail dot com  2009-11-25 19:17 -------
Whoops! My kernel does have one local change applied: the atop accounting
patches. Removing those fixes the problem. I'll go try to file a bug on atop
instead. (Fortunately, I really don't need those patches.)


-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |INVALID


http://sourceware.org/bugzilla/show_bug.cgi?id=10991

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