This is a note to let you know that I've just added the patch titled
nbd: Add the maximum limit of allocated index in nbd_dev_add
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nbd-add-the-maximum-limit-of-allocated-index-in-nbd_.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 456f7e7cba47667316050e9866ad8506c9e47f6f
Author: Zhong Jinghua <zhongjinghua@xxxxxxxxxx>
Date: Mon Jun 5 20:21:59 2023 +0800
nbd: Add the maximum limit of allocated index in nbd_dev_add
[ Upstream commit f12bc113ce904777fd6ca003b473b427782b3dde ]
If the index allocated by idr_alloc greater than MINORMASK >> part_shift,
the device number will overflow, resulting in failure to create a block
device.
Fix it by imiting the size of the max allocation.
Signed-off-by: Zhong Jinghua <zhongjinghua@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Link: https://lore.kernel.org/r/20230605122159.2134384-1-zhongjinghua@xxxxxxxxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 218aa7e419700..37994a7a1b6f4 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -1708,7 +1708,8 @@ static int nbd_dev_add(int index)
if (err == -ENOSPC)
err = -EEXIST;
} else {
- err = idr_alloc(&nbd_index_idr, nbd, 0, 0, GFP_KERNEL);
+ err = idr_alloc(&nbd_index_idr, nbd, 0,
+ (MINORMASK >> part_shift) + 1, GFP_KERNEL);
if (err >= 0)
index = err;
}
