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Commit 5f9d1fde authored by Shaohua Li's avatar Shaohua Li
Browse files

raid5: fix memory leak of bio integrity data 



Yi reported a memory leak of raid5 with DIF/DIX enabled disks. raid5
doesn't alloc/free bio, instead it reuses bios. There are two issues in
current code:
1. the code calls bio_init (from
init_stripe->raid5_build_block->bio_init) then bio_reset (ops_run_io).
The bio is reused, so likely there is integrity data attached. bio_init
will clear a pointer to integrity data and makes bio_reset can't release
the data
2. bio_reset is called before dispatching bio. After bio is finished,
it's possible we don't free bio's integrity data (eg, we don't call
bio_reset again)
Both issues will cause memory leak. The patch moves bio_init to stripe
creation and bio_reset to bio end io. This will fix the two issues.

Reported-by: default avatarYi Zhang <yizhan@redhat.com>
Signed-off-by: default avatarShaohua Li <shli@fb.com>
parent 27028626

drivers/md/raid5.c

+15 −7
Original line number Diff line number Diff line
@@ -1005,7 +1005,6 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s) 


			set_bit(STRIPE_IO_STARTED, &sh->state);



			bio_reset(bi);

			bi->bi_bdev = rdev->bdev;

			bio_set_op_attrs(bi, op, op_flags);

			bi->bi_end_io = op_is_write(op)
@@ -1057,7 +1056,6 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s) 


			set_bit(STRIPE_IO_STARTED, &sh->state);



			bio_reset(rbi);

			rbi->bi_bdev = rrdev->bdev;

			bio_set_op_attrs(rbi, op, op_flags);

			BUG_ON(!op_is_write(op));
@@ -1990,9 +1988,11 @@ static void raid_run_ops(struct stripe_head *sh, unsigned long ops_request) 
	put_cpu();

}



static struct stripe_head *alloc_stripe(struct kmem_cache *sc, gfp_t gfp)

static struct stripe_head *alloc_stripe(struct kmem_cache *sc, gfp_t gfp,

	int disks)

{

	struct stripe_head *sh;

	int i;



	sh = kmem_cache_zalloc(sc, gfp);

	if (sh) {
@@ -2001,6 +2001,12 @@ static struct stripe_head *alloc_stripe(struct kmem_cache *sc, gfp_t gfp) 
		INIT_LIST_HEAD(&sh->batch_list);

		INIT_LIST_HEAD(&sh->lru);

		atomic_set(&sh->count, 1);

		for (i = 0; i < disks; i++) {

			struct r5dev *dev = &sh->dev[i];



			bio_init(&dev->req);

			bio_init(&dev->rreq);

		}

	}

	return sh;

}
@@ -2008,7 +2014,7 @@ static int grow_one_stripe(struct r5conf *conf, gfp_t gfp) 
{

	struct stripe_head *sh;



	sh = alloc_stripe(conf->slab_cache, gfp);

	sh = alloc_stripe(conf->slab_cache, gfp, conf->pool_size);

	if (!sh)

		return 0;
@@ -2179,7 +2185,7 @@ static int resize_stripes(struct r5conf *conf, int newsize) 
	mutex_lock(&conf->cache_size_mutex);



	for (i = conf->max_nr_stripes; i; i--) {

		nsh = alloc_stripe(sc, GFP_KERNEL);

		nsh = alloc_stripe(sc, GFP_KERNEL, newsize);

		if (!nsh)

			break;
@@ -2311,6 +2317,7 @@ static void raid5_end_read_request(struct bio * bi) 
		(unsigned long long)sh->sector, i, atomic_read(&sh->count),

		bi->bi_error);

	if (i == disks) {

		bio_reset(bi);

		BUG();

		return;

	}
@@ -2414,6 +2421,7 @@ static void raid5_end_read_request(struct bio * bi) 
	clear_bit(R5_LOCKED, &sh->dev[i].flags);

	set_bit(STRIPE_HANDLE, &sh->state);

	raid5_release_stripe(sh);

	bio_reset(bi);

}



static void raid5_end_write_request(struct bio *bi)
@@ -2448,6 +2456,7 @@ static void raid5_end_write_request(struct bio *bi) 
		(unsigned long long)sh->sector, i, atomic_read(&sh->count),

		bi->bi_error);

	if (i == disks) {

		bio_reset(bi);

		BUG();

		return;

	}
@@ -2491,18 +2500,17 @@ static void raid5_end_write_request(struct bio *bi) 


	if (sh->batch_head && sh != sh->batch_head)

		raid5_release_stripe(sh->batch_head);

	bio_reset(bi);

}



static void raid5_build_block(struct stripe_head *sh, int i, int previous)

{

	struct r5dev *dev = &sh->dev[i];



	bio_init(&dev->req);

	dev->req.bi_io_vec = &dev->vec;

	dev->req.bi_max_vecs = 1;

	dev->req.bi_private = sh;



	bio_init(&dev->rreq);

	dev->rreq.bi_io_vec = &dev->rvec;

	dev->rreq.bi_max_vecs = 1;

	dev->rreq.bi_private = sh;