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authorAnanth N Mavinakayanahalli <ananth@in.ibm.com>2009-09-15 10:43:07 +0530
committerFrederic Weisbecker <fweisbec@gmail.com>2009-09-17 04:24:57 +0200
commit1f0ab40976460bc4673fa204ce917a725185d8f2 (patch)
treed854f402352917359729eb35e73bc34ee227c875 /kernel/kprobes.c
parent5a0d9050db4d1147722b42afef9011251b2651ee (diff)
kprobes: Prevent re-registration of the same kprobe
Prevent re-registration of the same kprobe. This situation, though unlikely, needs to be flagged since it can lead to a system crash if it's not handled. The core change itself is small, but the helper routine needed to be moved around a bit; hence the diffstat. Signed-off-by: Ananth N Mavinakayanahalli<ananth@in.ibm.com> Acked-by: Masami Hiramatsu <mhiramat@redhat.com> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Frank Ch. Eigler <fche@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Jason Baron <jbaron@redhat.com> Cc: K.Prasad <prasad@linux.vnet.ibm.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Tom Zanussi <tzanussi@gmail.com> LKML-Reference: <20090915051307.GB26458@in.ibm.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Diffstat (limited to 'kernel/kprobes.c')
-rw-r--r--kernel/kprobes.c58
1 files changed, 38 insertions, 20 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 00d01b0f9fee..b946761f84bd 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -676,6 +676,40 @@ static kprobe_opcode_t __kprobes *kprobe_addr(struct kprobe *p)
return (kprobe_opcode_t *)(((char *)addr) + p->offset);
}
+/* Check passed kprobe is valid and return kprobe in kprobe_table. */
+static struct kprobe * __kprobes __get_valid_kprobe(struct kprobe *p)
+{
+ struct kprobe *old_p, *list_p;
+
+ old_p = get_kprobe(p->addr);
+ if (unlikely(!old_p))
+ return NULL;
+
+ if (p != old_p) {
+ list_for_each_entry_rcu(list_p, &old_p->list, list)
+ if (list_p == p)
+ /* kprobe p is a valid probe */
+ goto valid;
+ return NULL;
+ }
+valid:
+ return old_p;
+}
+
+/* Return error if the kprobe is being re-registered */
+static inline int check_kprobe_rereg(struct kprobe *p)
+{
+ int ret = 0;
+ struct kprobe *old_p;
+
+ mutex_lock(&kprobe_mutex);
+ old_p = __get_valid_kprobe(p);
+ if (old_p)
+ ret = -EINVAL;
+ mutex_unlock(&kprobe_mutex);
+ return ret;
+}
+
int __kprobes register_kprobe(struct kprobe *p)
{
int ret = 0;
@@ -688,6 +722,10 @@ int __kprobes register_kprobe(struct kprobe *p)
return -EINVAL;
p->addr = addr;
+ ret = check_kprobe_rereg(p);
+ if (ret)
+ return ret;
+
preempt_disable();
if (!kernel_text_address((unsigned long) p->addr) ||
in_kprobes_functions((unsigned long) p->addr)) {
@@ -757,26 +795,6 @@ out:
}
EXPORT_SYMBOL_GPL(register_kprobe);
-/* Check passed kprobe is valid and return kprobe in kprobe_table. */
-static struct kprobe * __kprobes __get_valid_kprobe(struct kprobe *p)
-{
- struct kprobe *old_p, *list_p;
-
- old_p = get_kprobe(p->addr);
- if (unlikely(!old_p))
- return NULL;
-
- if (p != old_p) {
- list_for_each_entry_rcu(list_p, &old_p->list, list)
- if (list_p == p)
- /* kprobe p is a valid probe */
- goto valid;
- return NULL;
- }
-valid:
- return old_p;
-}
-
/*
* Unregister a kprobe without a scheduler synchronization.
*/

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