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bcache: avoid nr_stripes overflow in bcache_device_init() 

[ Upstream commit 65f0f017e7 ]

For some block devices which large capacity (e.g. 8TB) but small io_opt
size (e.g. 8 sectors), in bcache_device_init() the stripes number calcu-
lated by,
	DIV_ROUND_UP_ULL(sectors, d->stripe_size);
might be overflow to the unsigned int bcache_device->nr_stripes.

This patch uses the uint64_t variable to store DIV_ROUND_UP_ULL()
and after the value is checked to be available in unsigned int range,
sets it to bache_device->nr_stripes. Then the overflow is avoided.

Reported-and-tested-by: Ken Raeburn <raeburn@redhat.com>
Signed-off-by: Coly Li <colyli@suse.de>
Cc: stable@vger.kernel.org
Link: https://bugzilla.redhat.com/show_bug.cgi?id=1783075
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
5.4-rM2-2.2.x-imx-squashed
Coly Li 2020-07-25 20:00:21 +08:00 committed by Greg Kroah-Hartman
parent 9f4f7c08d5
commit b407539849
1 changed files with 6 additions and 6 deletions
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12
drivers/md/bcache/super.c
View File

@ -816,19 +816,19 @@ static int bcache_device_init(struct bcache_device *d, unsigned int block_size,
struct request_queue *q;
const size_t max_stripes = min_t(size_t, INT_MAX,
SIZE_MAX / sizeof(atomic_t));
size_t n;
uint64_t n;
int idx;
if (!d->stripe_size)
d->stripe_size = 1 << 31;
d->nr_stripes = DIV_ROUND_UP_ULL(sectors, d->stripe_size);
if (!d->nr_stripes || d->nr_stripes > max_stripes) {
pr_err("nr_stripes too large or invalid: %u (start sector beyond end of disk?)",
(unsigned int)d->nr_stripes);
n = DIV_ROUND_UP_ULL(sectors, d->stripe_size);
if (!n || n > max_stripes) {
pr_err("nr_stripes too large or invalid: %llu (start sector beyond end of disk?)\n",
n);
return -ENOMEM;
}
d->nr_stripes = n;
n = d->nr_stripes * sizeof(atomic_t);
d->stripe_sectors_dirty = kvzalloc(n, GFP_KERNEL);