Commit-ID: 2a4efa42450762cbfa5c5712aa4cc9f06924c9fd
Gitweb: http://git.kernel.org/tip/2a4efa42450762cbfa5c5712aa4cc9f06924c9fd
Author: Zhaolei <zhaolei@xxxxxxxxxxxxxx>
AuthorDate: Wed, 25 Mar 2009 12:06:05 +0800
Committer: Steven Rostedt <srostedt@xxxxxxxxxx>
CommitDate: Wed, 25 Mar 2009 17:45:36 -0400
ftrace: Using FTRACE_WARN_ON() to check "freed record" in ftrace_release()
"Because when we call ftrace_free_rec we change the rec->ip to point to the
next record in the chain. Something is very wrong if rec->ip >= s &&
rec->ip < e and the record is already free."
"Note, use FTRACE_WARN_ON() macro. This way it shuts down ftrace if it is
hit and helps to avoid further damage later."
-- Steven Rostedt <rostedt@xxxxxxxxxxx>
Signed-off-by: Zhao Lei <zhaolei@xxxxxxxxxxxxxx>
Signed-off-by: Steven Rostedt <srostedt@xxxxxxxxxx>
---
kernel/trace/ftrace.c | 9 +++++++--
1 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 7b8722b..1752a63 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -358,9 +358,14 @@ void ftrace_release(void *start, unsigned long size)
mutex_lock(&ftrace_lock);
do_for_each_ftrace_rec(pg, rec) {
- if ((rec->ip >= s) && (rec->ip < e) &&
- !(rec->flags & FTRACE_FL_FREE))
+ if ((rec->ip >= s) && (rec->ip < e)) {
+ /*
+ * rec->ip is changed in ftrace_free_rec()
+ * It should not between s and e if record was freed.
+ */
+ FTRACE_WARN_ON(rec->flags & FTRACE_FL_FREE);
ftrace_free_rec(rec);
+ }
} while_for_each_ftrace_rec();
mutex_unlock(&ftrace_lock);
}
--
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