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authorZhaolei <zhaolei@cn.fujitsu.com>2009-03-25 12:06:05 +0800
committerSteven Rostedt <srostedt@redhat.com>2009-03-25 17:45:36 -0400
commit2a4efa42450762cbfa5c5712aa4cc9f06924c9fd (patch)
tree70af0a079541af99dec634fc89ce317dee2f1a33
parent759ee0915dd713361e72facb78b66600b5712d65 (diff)
downloadop-kernel-dev-2a4efa42450762cbfa5c5712aa4cc9f06924c9fd.zip
op-kernel-dev-2a4efa42450762cbfa5c5712aa4cc9f06924c9fd.tar.gz
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@goodmis.org> Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> Signed-off-by: Steven Rostedt <srostedt@redhat.com>
-rw-r--r--kernel/trace/ftrace.c9
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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