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Trying to acquire global lock from systemtap module
- From: Anupama Chandwani <achandwani at vmware dot com>
- To: "systemtap at sourceware dot org" <systemtap at sourceware dot org>
- Date: Wed, 22 Jul 2009 10:14:38 -0700
- Subject: Trying to acquire global lock from systemtap module
Hi,
In my probe handler, I want to scan the task list using for_each_process(p).
For this I need to hold a read_lock on tasklist_lock.
tasklist_lock is a global data structure of type rwlock_t, and I am setting the probe on copy_process (from kernel/fork.c where tasklist_lock is defined)
But I am not able to dereference this address. Also when I do a read_lock(&tasklist_lock), i get following error while inserting module.
Error inserting module 'module_name.ko' : Unknown symbol in module
And dmesg tells me that the unknown symbol is 'tasklist_lock'
Any pointers?
Cheers,
Anupama