linux-kernel - Re: [PATCH] fs: System memory leak when running HTX with T10 DIF enabled

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Message-ID: <0fa90019-5b07-7afb-8915-17c54a22709b@fb.com>
Date:   Wed, 28 Jun 2017 12:34:15 -0600
From:   Jens Axboe <axboe@...com>
To:     Christoph Hellwig <hch@....de>, Keith Busch <keith.busch@...el.com>
CC:     <wenxiong@...ux.vnet.ibm.com>, <linux-kernel@...r.kernel.org>,
        <bjking@...ux.vnet.ibm.com>
Subject: Re: [PATCH] fs: System memory leak when running HTX with T10 DIF
 enabled

On 06/28/2017 12:31 PM, Christoph Hellwig wrote:
> On Wed, Jun 28, 2017 at 01:10:31PM -0400, Keith Busch wrote:
>> On Wed, Jun 28, 2017 at 11:32:51AM -0500, wenxiong@...ux.vnet.ibm.com wrote:
>>> diff --git a/fs/block_dev.c b/fs/block_dev.c
>>> index 519599d..e871444 100644
>>> --- a/fs/block_dev.c
>>> +++ b/fs/block_dev.c
>>> @@ -264,6 +264,10 @@ static void blkdev_bio_end_io_simple(struct bio *bio)
>>>  
>>>  	if (unlikely(bio.bi_error))
>>>  		return bio.bi_error;
>>> +
>>> +	if (bio_integrity(&bio))
>>> +		bio_integrity_free(&bio);
>>> +
>>>  	return ret;
>>>  }
>>
>> We don't want to leak the integrity payload in case of bi_error either.
> 
> And we should just call __bio_free.  Which btw every user of bio_init
> probably needs.

That's what I sent out. Here it is again. We should get this into 4.12,
so would be great with a review or two.


diff --git a/block/bio.c b/block/bio.c
index 888e7801c638..bdc6e6541278 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -240,7 +240,7 @@ struct bio_vec *bvec_alloc(gfp_t gfp_mask, int nr, unsigned long *idx,
 	return bvl;
 }
 
-static void __bio_free(struct bio *bio)
+void __bio_free(struct bio *bio)
 {
 	bio_disassociate_task(bio);
 
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 519599dddd36..d929f886ee7b 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -263,7 +263,10 @@ __blkdev_direct_IO_simple(struct kiocb *iocb, struct iov_iter *iter,
 		kfree(vecs);
 
 	if (unlikely(bio.bi_error))
-		return bio.bi_error;
+		ret = bio.bi_error;
+
+	__bio_free(&bio);
+
 	return ret;
 }
 
diff --git a/include/linux/bio.h b/include/linux/bio.h
index d1b04b0e99cf..4a29dc3db8cb 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -380,6 +380,7 @@ extern mempool_t *biovec_create_pool(int pool_entries);
 
 extern struct bio *bio_alloc_bioset(gfp_t, unsigned int, struct bio_set *);
 extern void bio_put(struct bio *);
+extern void __bio_free(struct bio *);
 
 extern void __bio_clone_fast(struct bio *, struct bio *);
 extern struct bio *bio_clone_fast(struct bio *, gfp_t, struct bio_set *);

-- 
Jens Axboe