From: Masami Hiramatsu <mhiramat@redhat.com>
Date: Tue, 6 Jan 2009 22:41:46 +0000 (-0800)
Subject: kprobes: bugfix: try_module_get even if calling_mod is NULL
X-Git-Tag: v2.6.29-rc1~317
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=bc2f70151fe7a117dbe8347edc5a877e749572a3;p=pandora-kernel.git

kprobes: bugfix: try_module_get even if calling_mod is NULL

When someone called register_*probe() from kernel-core code(not from
module) and that probes a kernel module, users can remove the probed
module because kprobe doesn't increment reference counter of the module.
(on the other hand, if the kernel-module calls register_*probe, kprobe
increments refcount of the probed module.)

Currently, we have no register_*probe() calling from kernel-core(except
smoke-test, but the smoke-test doesn't probe module), so there is no real
bugs.  But the logic is wrong(or not fair) and it can causes a problem
when someone might want to probe module from kernel.

After this patch is applied, even if someone put register_*probe() call in
the kernel-core code, it increments the reference counter of the probed
module, and it prevents user to remove the module until stopping probing
it.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

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