This is a note to let you know that I've just added the patch titled
[PATCH 5.10.y stable v2] block: unhash blkdev part inode when the part is deleted
to the 5.10-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:
block-unhash-blkdev-part-inode-when-the-part-is-deleted.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ming.lei@xxxxxxxxxx Mon Dec 5 17:35:21 2022
From: Ming Lei <ming.lei@xxxxxxxxxx>
Date: Mon, 5 Dec 2022 21:27:39 +0800
Subject: [PATCH 5.10.y stable v2] block: unhash blkdev part inode when the part is deleted
To: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>, stable@xxxxxxxxxxxxxxx
Cc: Jens Axboe <axboe@xxxxxxxxx>, linux-block@xxxxxxxxxxxxxxx, Ming Lei <ming.lei@xxxxxxxxxx>, Shiwei Cui <cuishw@xxxxxxxxxx>, Christoph Hellwig <hch@xxxxxx>, Jan Kara <jack@xxxxxxx>
Message-ID: <20221205132739.844399-1-ming.lei@xxxxxxxxxx>
v5.11 changes the blkdev lookup mechanism completely since commit
22ae8ce8b892 ("block: simplify bdev/disk lookup in blkdev_get"),
and small part of the change is to unhash part bdev inode when
deleting partition. Turns out this kind of change does fix one
nasty issue in case of BLOCK_EXT_MAJOR:
1) when one partition is deleted & closed, disk_put_part() is always
called before bdput(bdev), see blkdev_put(); so the part's devt can
be freed & re-used before the inode is dropped
2) then new partition with same devt can be created just before the
inode in 1) is dropped, then the old inode/bdev structurein 1) is
re-used for this new partition, this way causes use-after-free and
kernel panic.
It isn't possible to backport the whole big patchset of "merge struct
block_device and struct hd_struct v4" for addressing this issue.
https://lore.kernel.org/linux-block/20201128161510.347752-1-hch@xxxxxx/
So fixes it by unhashing part bdev in delete_partition(), and this way
is actually aligned with v5.11+'s behavior.
Reported-by: Shiwei Cui <cuishw@xxxxxxxxxx>
Tested-by: Shiwei Cui <cuishw@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
Acked-by: Jens Axboe <axboe@xxxxxxxxx>
---
block/partitions/core.c | 7 +++++++
1 file changed, 7 insertions(+)
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -329,6 +329,7 @@ void delete_partition(struct hd_struct *
struct gendisk *disk = part_to_disk(part);
struct disk_part_tbl *ptbl =
rcu_dereference_protected(disk->part_tbl, 1);
+ struct block_device *bdev;
/*
* ->part_tbl is referenced in this part's release handler, so
@@ -346,6 +347,12 @@ void delete_partition(struct hd_struct *
* "in-use" until we really free the gendisk.
*/
blk_invalidate_devt(part_devt(part));
+
+ bdev = bdget_part(part);
+ if (bdev) {
+ remove_inode_hash(bdev->bd_inode);
+ bdput(bdev);
+ }
percpu_ref_kill(&part->ref);
}
Patches currently in stable-queue which might be from ming.lei@xxxxxxxxxx are
queue-5.10/block-unhash-blkdev-part-inode-when-the-part-is-deleted.patch
