bcache: Revert "bcache: use bvec_virt"
authorColy Li <colyli@suse.de>
Wed, 3 Nov 2021 15:10:41 +0000 (23:10 +0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 18 Nov 2021 18:17:17 +0000 (19:17 +0100)
commitac8ffb5d9dfbdb965f72732a0e214cfcdc8eb44c
tree6b770443295ec23405a397e5a2c6f512e5938283
parentd6a300977ac9fd714303049a37e0f5f74ef5e6c9
bcache: Revert "bcache: use bvec_virt"

commit 2878feaed543c35f9dbbe6d8ce36fb67ac803eef upstream.

This reverts commit 2fd3e5efe791946be0957c8e1eed9560b541fe46.

The above commit replaces page_address(bv->bv_page) by bvec_virt(bv) to
avoid directly access to bv->bv_page, but in situation bv->bv_offset is
not zero and page_address(bv->bv_page) is not equal to bvec_virt(bv). In
such case a memory corruption may happen because memory in next page is
tainted by following line in do_btree_node_write(),
memcpy(bvec_virt(bv), addr, PAGE_SIZE);

This patch reverts the mentioned commit to avoid the memory corruption.

Fixes: 2fd3e5efe791 ("bcache: use bvec_virt")
Signed-off-by: Coly Li <colyli@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org # 5.15
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211103151041.70516-1-colyli@suse.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/md/bcache/btree.c