* [PATCH stable 4.14.y] block: unhash blkdev part inode when the part is deleted
@ 2022-12-13 7:16 Ming Lei
2022-12-13 7:18 ` kernel test robot
0 siblings, 1 reply; 2+ messages in thread
From: Ming Lei @ 2022-12-13 7:16 UTC (permalink / raw)
To: Greg Kroah-Hartman, stable
Cc: Jens Axboe, linux-block, Ming Lei, Shiwei Cui, Christoph Hellwig,
Jan Kara
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@lst.de/
So fixes it by unhashing part bdev in delete_partition(), and this way
is actually aligned with v5.11+'s behavior.
Backported from the following 5.10.y commit:
5f2f77560591 ("block: unhash blkdev part inode when the part is deleted")
Reported-by: Shiwei Cui <cuishw@inspur.com>
Tested-by: Shiwei Cui <cuishw@inspur.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
block/partition-generic.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/block/partition-generic.c b/block/partition-generic.c
index db57cced9b98..68bd04d044b9 100644
--- a/block/partition-generic.c
+++ b/block/partition-generic.c
@@ -270,6 +270,7 @@ void delete_partition(struct gendisk *disk, int partno)
struct disk_part_tbl *ptbl =
rcu_dereference_protected(disk->part_tbl, 1);
struct hd_struct *part;
+ struct block_device *bdev;
if (partno >= ptbl->len)
return;
@@ -283,6 +284,11 @@ void delete_partition(struct gendisk *disk, int partno)
kobject_put(part->holder_dir);
device_del(part_to_dev(part));
+ bdev = bdget(part_devt(part));
+ if (bdev) {
+ remove_inode_hash(bdev->bd_inode);
+ bdput(bdev);
+ }
hd_struct_kill(part);
}
--
2.38.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH stable 4.14.y] block: unhash blkdev part inode when the part is deleted
2022-12-13 7:16 [PATCH stable 4.14.y] block: unhash blkdev part inode when the part is deleted Ming Lei
@ 2022-12-13 7:18 ` kernel test robot
0 siblings, 0 replies; 2+ messages in thread
From: kernel test robot @ 2022-12-13 7:18 UTC (permalink / raw)
To: Ming Lei; +Cc: stable, oe-kbuild-all
Hi,
Thanks for your patch.
FYI: kernel test robot notices the stable kernel rule is not satisfied.
Rule: 'Cc: stable@vger.kernel.org' or 'commit <sha1> upstream.'
Subject: [PATCH stable 4.14.y] block: unhash blkdev part inode when the part is deleted
Link: https://lore.kernel.org/stable/20221213071627.1197786-1-ming.lei%40redhat.com
The check is based on https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
--
0-DAY CI Kernel Test Service
https://01.org/lkp
^ permalink raw reply [flat|nested] 2+ messages in thread
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2022-12-13 7:18 ` kernel test robot
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