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authorSteven Rostedt <srostedt@redhat.com>2010-10-18 10:38:58 -0400
committerSteven Rostedt <rostedt@goodmis.org>2010-10-29 12:55:55 -0400
commitde31c3ca8179d7c21def7ecb56e4fec0c8659d36 (patch)
tree63a488e1e3778c328074aaa47cb062b910d9c902 /kernel
parent91bad2f8d3057482b9afb599f14421b007136960 (diff)
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jump label: Fix error with preempt disable holding mutex
Kprobes and jump label were having a race between mutexes that was fixed by reordering the jump label. But this reordering moved the jump label mutex into a preempt disable location. This patch does a little fiddling to move the grabbing of the jump label mutex from inside the preempt disable section and still keep the order correct between the mutex and the kprobes lock. Reported-by: Ingo Molnar <mingo@elte.hu> Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Jason Baron <jbaron@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/kprobes.c26
1 files changed, 13 insertions, 13 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 9437e14f36b..9737a76e106 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1145,17 +1145,13 @@ int __kprobes register_kprobe(struct kprobe *p)
if (ret)
return ret;
- preempt_disable();
jump_label_lock();
+ preempt_disable();
if (!kernel_text_address((unsigned long) p->addr) ||
in_kprobes_functions((unsigned long) p->addr) ||
ftrace_text_reserved(p->addr, p->addr) ||
- jump_label_text_reserved(p->addr, p->addr)) {
- preempt_enable();
- jump_label_unlock();
- return -EINVAL;
- }
- jump_label_unlock();
+ jump_label_text_reserved(p->addr, p->addr))
+ goto fail_with_jump_label;
/* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */
p->flags &= KPROBE_FLAG_DISABLED;
@@ -1169,10 +1165,9 @@ int __kprobes register_kprobe(struct kprobe *p)
* We must hold a refcount of the probed module while updating
* its code to prohibit unexpected unloading.
*/
- if (unlikely(!try_module_get(probed_mod))) {
- preempt_enable();
- return -EINVAL;
- }
+ if (unlikely(!try_module_get(probed_mod)))
+ goto fail_with_jump_label;
+
/*
* If the module freed .init.text, we couldn't insert
* kprobes in there.
@@ -1180,11 +1175,11 @@ int __kprobes register_kprobe(struct kprobe *p)
if (within_module_init((unsigned long)p->addr, probed_mod) &&
probed_mod->state != MODULE_STATE_COMING) {
module_put(probed_mod);
- preempt_enable();
- return -EINVAL;
+ goto fail_with_jump_label;
}
}
preempt_enable();
+ jump_label_unlock();
p->nmissed = 0;
INIT_LIST_HEAD(&p->list);
@@ -1226,6 +1221,11 @@ out:
module_put(probed_mod);
return ret;
+
+fail_with_jump_label:
+ preempt_enable();
+ jump_label_unlock();
+ return -EINVAL;
}
EXPORT_SYMBOL_GPL(register_kprobe);