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authorMike Snitzer <snitzer@redhat.com>2020-01-27 22:07:23 +0300
committerMike Snitzer <snitzer@redhat.com>2020-01-27 22:52:36 +0300
commit47ace7e012b9f7ad71d43ac9063d335ea3d6820b (patch)
tree2b45907e46c5531c2fb824a68ad4aa5b63ce0f5c /drivers/md/dm.c
parentdcd195071f22d4770911ca46694ca398b6d5101d (diff)
downloadlinux-47ace7e012b9f7ad71d43ac9063d335ea3d6820b.tar.xz
dm: fix potential for q->make_request_fn NULL pointer
Move blk_queue_make_request() to dm.c:alloc_dev() so that q->make_request_fn is never NULL during the lifetime of a DM device (even one that is created without a DM table). Otherwise generic_make_request() will crash simply by doing: dmsetup create -n test mount /dev/dm-N /mnt While at it, move ->congested_data initialization out of dm.c:alloc_dev() and into the bio-based specific init method. Reported-by: Stefan Bader <stefan.bader@canonical.com> BugLink: https://bugs.launchpad.net/bugs/1860231 Fixes: ff36ab34583a ("dm: remove request-based logic from make_request_fn wrapper") Depends-on: c12c9a3c3860c ("dm: various cleanups to md->queue initialization code") Cc: stable@vger.kernel.org Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md/dm.c')
-rw-r--r--drivers/md/dm.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index e8f9661a10a1..b89f07ee2eff 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1859,6 +1859,7 @@ static void dm_init_normal_md_queue(struct mapped_device *md)
/*
* Initialize aspects of queue that aren't relevant for blk-mq
*/
+ md->queue->backing_dev_info->congested_data = md;
md->queue->backing_dev_info->congested_fn = dm_any_congested;
}
@@ -1949,7 +1950,12 @@ static struct mapped_device *alloc_dev(int minor)
if (!md->queue)
goto bad;
md->queue->queuedata = md;
- md->queue->backing_dev_info->congested_data = md;
+ /*
+ * default to bio-based required ->make_request_fn until DM
+ * table is loaded and md->type established. If request-based
+ * table is loaded: blk-mq will override accordingly.
+ */
+ blk_queue_make_request(md->queue, dm_make_request);
md->disk = alloc_disk_node(1, md->numa_node_id);
if (!md->disk)
@@ -2264,7 +2270,6 @@ int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t)
case DM_TYPE_DAX_BIO_BASED:
case DM_TYPE_NVME_BIO_BASED:
dm_init_normal_md_queue(md);
- blk_queue_make_request(md->queue, dm_make_request);
break;
case DM_TYPE_NONE:
WARN_ON_ONCE(true);