From: Coly Li <colyli@suse.de>
To: linux-bcache@vger.kernel.org
Cc: linux-block@vger.kernel.org, Coly Li <colyli@suse.de>,
Ken Raeburn <raeburn@redhat.com>,
stable@vger.kernel.org
Subject: [PATCH v2 1/2] bcache: avoid nr_stripes overflow in bcache_device_init()
Date: Mon, 13 Jul 2020 19:15:00 +0800 [thread overview]
Message-ID: <20200713111501.19061-1-colyli@suse.de> (raw)
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-by: Ken Raeburn <raeburn@redhat.com>
Signed-off-by: Coly Li <colyli@suse.de>
Link: https://bugzilla.redhat.com/show_bug.cgi?id=1783075
Cc: stable@vger.kernel.org
---
Changelog:
v2: Improve overflow fix on 32bit machine, suggested by Jens and Ken.
v1: initial version.
drivers/md/bcache/super.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index a239fcaec70b..7615be9d4498 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -886,19 +886,19 @@ 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?)\n",
- (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);
--
2.26.2
next reply other threads:[~2020-07-13 11:15 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-13 11:15 Coly Li [this message]
2020-07-13 11:15 ` [PATCH v2 2/2] bcche: fix overflow in offset_to_stripe() Coly Li
2020-07-17 17:08 ` Sasha Levin
2020-07-17 17:08 ` [PATCH v2 1/2] bcache: avoid nr_stripes overflow in bcache_device_init() Sasha Levin
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