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SubjectRe: [PATCH] kprobes/x86: opt: free optinsn cache when range check fails

Hi Ingo,

Could you pull this for a bugfix of a memory leak?

(2014/08/27 21:15), Wang Nan wrote:
> On 2014/7/29 9:43, Masami Hiramatsu wrote:
>> (2014/07/28 21:20), Wang Nan wrote:
>>> This patch frees optinsn slot when range check error to prevent memory
>>> leaks. Before this patch, cache entry in kprobe_insn_cache won't be
>>> freed if kprobe optimizing fails due to range check failure.
>>>
>>> Signed-off-by: Wang Nan <wangnan0@huawei.com>
>>
>> Oops, thank you for finding it!
>>
>> Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
>>
>
> Hi Masami Hiramatsu,
>
> I don't find this patch in newest upstream. Is there any problem?
>
>> BTW, would you really have hit this error?
>> I'd like to know the case if this really happens.
>>
>>> ---
>>> arch/x86/kernel/kprobes/opt.c | 4 +++-
>>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c
>>> index f304773..f1314d0 100644
>>> --- a/arch/x86/kernel/kprobes/opt.c
>>> +++ b/arch/x86/kernel/kprobes/opt.c
>>> @@ -338,8 +338,10 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe *op)
>>> * a relative jump.
>>> */
>>> rel = (long)op->optinsn.insn - (long)op->kp.addr + RELATIVEJUMP_SIZE;
>>> - if (abs(rel) > 0x7fffffff)
>>> + if (abs(rel) > 0x7fffffff) {
>>> + __arch_remove_optimized_kprobe(op, 0);
>>> return -ERANGE;
>>> + }
>>>
>>> buf = (u8 *)op->optinsn.insn;
>>>
>>>
>>
>>
>
>
>


--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com




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