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| author |   Masami Hiramatsu <mhiramat@redhat.com> | 2009-01-06 14:41:46 -0800 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2009-01-06 15:59:20 -0800 |
| commit | bc2f70151fe7a117dbe8347edc5a877e749572a3 (patch) | |
| tree | 930634f100acb38baa597f840b5b12bec750c66e | |
| parent | drivers/spi: move a dereference below a NULL test (diff) | |
| download | linux-dev-bc2f70151fe7a117dbe8347edc5a877e749572a3.tar.xz linux-dev-bc2f70151fe7a117dbe8347edc5a877e749572a3.zip | |
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>
| -rw-r--r-- | kernel/kprobes.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 9f8a3f25259a..3afd354c46f1 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -634,7 +634,7 @@ static int __kprobes __register_kprobe(struct kprobe *p, * avoid incrementing the module refcount, so as to allow * unloading of self probing modules. */ - if (calling_mod && calling_mod != probed_mod) { + if (calling_mod != probed_mod) { if (unlikely(!try_module_get(probed_mod))) { preempt_enable(); return -EINVAL; |