dm: fix alloc_dax error handling in alloc_dev

[ Upstream commit d751939235b9b7bc4af15f90a3e99288a8b844a7 ]

Make sure ->dax_dev is NULL on error so that the cleanup path doesn't
trip over an ERR_PTR.

Reported-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211129102203.2243509-2-hch@lst.de
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 76d9da4..671bb45 100644 (file)
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1794,8 +1794,10 @@ static struct mapped_device *alloc_dev(int minor)
        if (IS_ENABLED(CONFIG_DAX_DRIVER)) {
                md->dax_dev = alloc_dax(md, md->disk->disk_name,
                                        &dm_dax_ops, 0);
-               if (IS_ERR(md->dax_dev))
+               if (IS_ERR(md->dax_dev)) {
+                       md->dax_dev = NULL;
                        goto bad;
+               }
        }
 
        format_dev_t(md->name, MKDEV(_major, minor));