diff options
| author | Mike Snitzer <snitzer@redhat.com> | 2020-01-27 14:07:23 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-02-14 16:32:23 -0500 |
| commit | ad6026d244ef0a1fa4823efed0abcfad11a06849 (patch) | |
| tree | a34bce945c18fc4a3fd6d4e0f7f81936db45f33f | |
| parent | f2cfc606d03c00558393d8688b64b33bcb1de710 (diff) | |
dm: fix potential for q->make_request_fn NULL pointer
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>
[smb: adjusted for context and dm_init_md_queue() exitsting in older
kernels]
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/md/dm.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index a56008b2e7c2..02ba6849f89d 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1647,7 +1647,6 @@ void dm_init_md_queue(struct mapped_device *md) * - must do so here (in alloc_dev callchain) before queue is used */ md->queue->queuedata = md; - md->queue->backing_dev_info->congested_data = md; } void dm_init_normal_md_queue(struct mapped_device *md) @@ -1658,6 +1657,7 @@ 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; } @@ -1750,6 +1750,12 @@ static struct mapped_device *alloc_dev(int minor) goto bad; dm_init_md_queue(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, numa_node_id); if (!md->disk) @@ -2055,7 +2061,6 @@ int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t) 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); /* * DM handles splitting bios as needed. Free the bio_split bioset * since it won't be used (saves 1 process per bio-based DM device). |