| From 47ace7e012b9f7ad71d43ac9063d335ea3d6820b Mon Sep 17 00:00:00 2001 |
| From: Mike Snitzer <snitzer@redhat.com> |
| Date: Mon, 27 Jan 2020 14:07:23 -0500 |
| Subject: dm: fix potential for q->make_request_fn NULL pointer |
| |
| From: Mike Snitzer <snitzer@redhat.com> |
| |
| commit 47ace7e012b9f7ad71d43ac9063d335ea3d6820b upstream. |
| |
| 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> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/md/dm.c | 9 +++++++-- |
| 1 file changed, 7 insertions(+), 2 deletions(-) |
| |
| --- a/drivers/md/dm.c |
| +++ b/drivers/md/dm.c |
| @@ -1819,6 +1819,7 @@ static void dm_init_normal_md_queue(stru |
| /* |
| * 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; |
| } |
| |
| @@ -1913,7 +1914,12 @@ static struct mapped_device *alloc_dev(i |
| 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) |
| @@ -2242,7 +2248,6 @@ int dm_setup_md_queue(struct mapped_devi |
| case DM_TYPE_BIO_BASED: |
| case DM_TYPE_DAX_BIO_BASED: |
| dm_init_normal_md_queue(md); |
| - blk_queue_make_request(md->queue, dm_make_request); |
| break; |
| case DM_TYPE_NVME_BIO_BASED: |
| dm_init_normal_md_queue(md); |