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[Bug runtime/6646] SystemTap scripts fail with an Oops on x86
- From: "ananth at in dot ibm dot com" <sourceware-bugzilla at sourceware dot org>
- To: systemtap at sources dot redhat dot com
- Date: 17 Jun 2008 07:12:52 -0000
- Subject: [Bug runtime/6646] SystemTap scripts fail with an Oops on x86
- References: <20080616053045.6646.ananth@in.ibm.com>
- Reply-to: sourceware-bugzilla at sourceware dot org
------- Additional Comments From ananth at in dot ibm dot com 2008-06-17 07:12 -------
The NULL pointer deref is coming from the modules_op->start() call in
runtime/transport/symbols.c:
606 static int _stp_init_modules(void)
....
611 const struct seq_operations *modules_op = (const struct seq_oper
ations *)_stp_kallsyms_lookup_name("modules_op");
612
......
617
618 /* Use the seq_file interface to safely get a list of installed
modules */
619 res = modules_op->start(NULL, &pos); <-- here!
620 while (res) {
The reason is that _stp_kallsyms_lookup_name returns an incorrect address (it
returns c11a0e0c while the actual address is c05a0e0c):
[root@jataayu mod]# cat /proc/kallsyms |grep modules_op
c048eee9 t modules_open
c05a0e0c R modules_op
c05a40d8 r proc_modules_operations
I've verified that *(c11a0e0c) is NULL causing the BUG.
--
http://sourceware.org/bugzilla/show_bug.cgi?id=6646
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