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SubjectRe: [PATCH] ftrace: Avoid double-free of dyn_ftrace
Date
* From: "Ingo Molnar" <mingo@elte.hu>
> * Zhaolei <zhaolei@cn.fujitsu.com> wrote:
>
>> If dyn_ftrace is free before ftrace_release(),
>> ftrace_release() will free it again and make
>> ftrace_free_records wrong.
>>
>> Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
>> ---
>> kernel/trace/ftrace.c | 3 ++-
>> 1 files changed, 2 insertions(+), 1 deletions(-)
>>
>> diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
>> index d33d306..26c45aa 100644
>> --- a/kernel/trace/ftrace.c
>> +++ b/kernel/trace/ftrace.c
>> @@ -356,7 +356,8 @@ 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))
>> + if ((rec->ip >= s) && (rec->ip < e) &&
>> + !(rec->flags & FTRACE_FL_FREE))
>> ftrace_free_rec(rec);
>
> Applied to tip:tracing/ftrace, thanks!
>
> I'm wondering, did you trigger this in practice (if yes, how?),
> or have you found it via code review?
Hello, Ingo

It is found via code review.

B.R.
Zhaolei
>
> Ingo
>
>
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