runtime error

[Wenji Huang]

Hi,

Found that runtime error for latest source code, even the simplest stap 
script.

[root@dhcp-beijing-cdc-10-182-120-233 wjhuang]# stap -vve 'probe begin 
{printf("hello world")}'
SystemTap translator/driver (version 0.7/0.131 git branch master, commit 
7eb702bf)
Copyright (C) 2005-2008 Red Hat, Inc. and others
This is free software; see the source for copying conditions.
Created temporary directory "/tmp/staphWf0IN"
Searched '/usr/local/share/systemtap/tapset/i686/*.stp', found 1
Searched '/usr/local/share/systemtap/tapset/*.stp', found 39
Pass 1: parsed user script and 40 library script(s) in 
330usr/70sys/984real ms.
Pass 2: analyzed script: 1 probe(s), 0 function(s), 0 embed(s), 0 
global(s) in 10usr/0sys/16real ms.
Pass 3: translated to C into 
"/tmp/staphWf0IN/stap_95b1ffee2099cfe87ed71f43e80c3ce5_152.c" in 
20usr/30sys/434real ms.
Running make -C "/lib/modules/2.6.25-rc6/build" M="/tmp/staphWf0IN" 
modules >/dev/null
Pass 4: compiled C into "stap_95b1ffee2099cfe87ed71f43e80c3ce5_152.ko" 
in 4440usr/1890sys/10204real ms.
Copying /tmp/staphWf0IN/stap_95b1ffee2099cfe87ed71f43e80c3ce5_152.ko to 
/root/.systemtap/cache/95/stap_95b1ffee2099cfe87ed71f43e80c3ce5_152.ko
Copying /tmp/staphWf0IN/stap_95b1ffee2099cfe87ed71f43e80c3ce5_152.c to 
/root/.systemtap/cache/95/stap_95b1ffee2099cfe87ed71f43e80c3ce5_152.c
Pass 5: starting run.
Running /usr/local/bin/staprun -v 
/tmp/staphWf0IN/stap_95b1ffee2099cfe87ed71f43e80c3ce5_152.ko
Pass 5: run completed in 10usr/50sys/160real ms.
Pass 5: run failed.  Try again with more '-v' (verbose) options.
Running rm -rf /tmp/staphWf0IN

The module couldn't be unloaded:
[root@dhcp-beijing-cdc-10-182-120-233 wjhuang]# /sbin/lsmod
Module                  Size  Used by
stap_95b1ffee2099cfe87ed71f43e80c3ce5_152   322364  1
ipv6                  182308  16

Dmesg say:
BUG: unable to handle kernel NULL pointer dereference at 00000000
IP: [<00000000>]
*pde = 00000000
Oops: 0000 [#1]
Modules linked in: stap_95b1ffee2099cfe87ed71f43e80c3ce5_152(+) ipv6

Pid: 3873, comm: staprun Not tainted (2.6.25-rc6 #5)
EIP: 0060:[<00000000>] EFLAGS: 00010246 CPU: 0
EIP is at 0x0
EAX: 00000000 EBX: cf580200 ECX: 00000000 EDX: cfa6beb8
ESI: c119cc60 EDI: cf527220 EBP: d0932080 ESP: cfa6bdac
  DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 0068
Process staprun (pid: 3873, ti=cfa6a000 task=cf904000 task.ti=cfa6a000)
Stack: d08e8e62 cf152588 00000000 74737973 61746d65 c0290070 cf904028 
cf152588
        c0386460 cf904000 c010df0c 00000001 c03864c0 cf807f30 00000001 
00000005
        cf807f30 00000001 00000005 70617473 6235395f 65666631 39303265 
65666339
Call Trace:
  [<d08e8e62>] _stp_transport_init+0x379/0x495 
[stap_95b1ffee2099cfe87ed71f43e80c3ce5_152]
  [<c0290070>] rwsem_down_failed_common+0x13/0x13c
  [<c010df0c>] check_preempt_wakeup+0x60/0x8f
  [<c01b52d4>] ida_get_new_above+0xb4/0x12e
  [<c0172c4f>] sysfs_ilookup_test+0x0/0xd
  [<c0154713>] ifind+0xa/0x44
  [<c01547a0>] ilookup5_nowait+0x27/0x2c
  [<c0130852>] free_pages_bulk+0xc1/0x1d0
  [<c0126ab9>] sys_init_module+0x1387/0x14eb
  [<c01b7f86>] simple_strtoull+0x0/0xdc
  [<c01151d5>] sys_capset+0x29f/0x2ba
  [<c01036a6>] sysenter_past_esp+0x5f/0x85
  =======================
Code:  Bad EIP value.
EIP: [<00000000>] 0x0 SS:ESP 0068:cfa6bdac
---[ end trace 952d114c5bfd31b1 ]---

Environment:
[wjhuang@dhcp-beijing-cdc-10-182-120-233 ~]$ gcc -v
Using built-in specs.
Target: i386-redhat-linux
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man 
--infodir=/usr/share/info --enable-shared --enable-threads=posix 
--enable-checking=release --with-system-zlib --enable-__cxa_atexit 
--disable-libunwind-exceptions --enable-libgcj-multifile 
--enable-languages=c,c++,objc,obj-c++,java,fortran,ada 
--enable-java-awt=gtk --disable-dssi --enable-plugin 
--with-java-home=/usr/lib/jvm/java-1.4.2-gcj-1.4.2.0/jre 
--with-cpu=generic --host=i386-redhat-linux
Thread model: posix
gcc version 4.1.1 20070105 (Red Hat 4.1.1-52)
[wjhuang@dhcp-beijing-cdc-10-182-120-233 ~]$ uname -r
2.6.25-rc6

I guess some problem in stapio. And need the facility of unloading stap 
module/terminating stap process in case of error.

Regards,
Wenji