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    Subject[PATCH 5.15 885/917] bcache: Revert "bcache: use bvec_virt"
    Date
    From: Coly Li <colyli@suse.de>

    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 | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    --- a/drivers/md/bcache/btree.c
    +++ b/drivers/md/bcache/btree.c
    @@ -378,7 +378,7 @@ static void do_btree_node_write(struct b
    struct bvec_iter_all iter_all;

    bio_for_each_segment_all(bv, b->bio, iter_all) {
    - memcpy(bvec_virt(bv), addr, PAGE_SIZE);
    + memcpy(page_address(bv->bv_page), addr, PAGE_SIZE);
    addr += PAGE_SIZE;
    }


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