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Subject: Re: [PATCH] lightnvm: pblk: fix use-after-free bug
To:     =?UTF-8?Q?Matias_Bj=c3=b8rling?= <mb@lightnvm.io>,
        Igor Konopko <igor.j.konopko@intel.com>,
        Jens Axboe <axboe@kernel.dk>
Cc:     linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20181222073952.GA11561@embeddedor>
 <1992ea52-cc13-c704-4653-7fbe667b1c5a@lightnvm.io>
From:   "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Message-ID: <b25d175f-ec2d-5906-bd90-68c12c2c975d@embeddedor.com>
Date:   Sat, 22 Dec 2018 13:01:09 -0600
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On 12/22/18 12:30 PM, Matias Bjørling wrote:
> On 12/22/18 8:39 AM, Gustavo A. R. Silva wrote:
>> Remove one of the calls to function bio_put(), so *bio* is only
>> freed once.
>>
>> Notice that bio is being dereferenced in bio_put(), hence leading to
>> a use-after-free bug once *bio* has already been freed.
>>
>> Addresses-Coverity-ID: 1475952 ("Use after free")
>> Fixes: 55d8ec35398e ("lightnvm: pblk: support packed metadata")
>> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
>> ---
>>   drivers/lightnvm/pblk-recovery.c | 1 -
>>   1 file changed, 1 deletion(-)
>>
>> diff --git a/drivers/lightnvm/pblk-recovery.c 
>> b/drivers/lightnvm/pblk-recovery.c
>> index 3fcf062d752c..5ee20da7bdb3 100644
>> --- a/drivers/lightnvm/pblk-recovery.c
>> +++ b/drivers/lightnvm/pblk-recovery.c
>> @@ -418,7 +418,6 @@ static int pblk_recov_scan_oob(struct pblk *pblk, 
>> struct pblk_line *line,
>>       if (ret) {
>>           pblk_err(pblk, "I/O submission failed: %d\n", ret);
>>           bio_put(bio);
>> -        bio_put(bio);
>>           return ret;
>>       }
>>
> 
> Thanks Gustavo. I missed that one.
> 
> Jens, if possible could you please pick this up?
> 
> Happy holidays!
> 

Glad to help. :)

Happy holidays everybody.

--
Gustavo