Re: [PATCH 0/4] ftrace: prevent ftrace modifications while beingkprobe'd

From: Abhishek Sagar
Date: Thu Jun 26 2008 - 13:48:22 EST


Ingo Molnar wrote:
> best would be a delta patch against tip/master to fix up whatever is
> still missing.

Here is the merge fixup for tip/master (and tip/tracing/ftrace).

Signed-off-by: Abhishek Sagar <sagar.abhishek@xxxxxxxxx>
---

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 85e8413..0f271c4 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -502,8 +502,12 @@ static void ftrace_replace_code(int enable)
continue;

/* ignore updates to this record's mcount site */
- if (get_kprobe((void *)rec->ip))
+ if (get_kprobe((void *)rec->ip)) {
+ freeze_record(rec);
continue;
+ } else {
+ unfreeze_record(rec);
+ }

failed = __ftrace_replace_code(rec, old, new, enable);
if (failed && (rec->flags & FTRACE_FL_CONVERTED)) {
@@ -740,7 +744,10 @@ static int __ftrace_update_code(void *ignore)
ftrace_del_hash(p);
INIT_HLIST_NODE(&p->node);
hlist_add_head(&p->node, &temp_list);
+ freeze_record(p);
continue;
+ } else {
+ unfreeze_record(p);
}

/* convert record (i.e, patch mcount-call with NOP) */
--
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