From 2a4efa42450762cbfa5c5712aa4cc9f06924c9fd Mon Sep 17 00:00:00 2001 From: Zhaolei Date: Wed, 25 Mar 2009 12:06:05 +0800 Subject: [PATCH] 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 Signed-off-by: Zhao Lei Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 7b8722baf15..1752a63f37c 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); } -- 2.39.2