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 16:30:02 -0500 |
| commit | 354fc8ad0c0094d22481f6272294a226476ac19c (patch) | |
| tree | 159a9412cbb1ab82eaed257a7c7e36ee17d45170 | |
| parent | 7bd751f1c30f6a2a870169c0501875f1ca2d9416 (diff) | |
| download | linux-stable-354fc8ad0c0094d22481f6272294a226476ac19c.tar.gz linux-stable-354fc8ad0c0094d22481f6272294a226476ac19c.tar.bz2 linux-stable-354fc8ad0c0094d22481f6272294a226476ac19c.zip | |
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, and congested_data embedded in backing_dev_info, and
dm_init_normal_md_queue() was called dm_init_old_md_queue()]
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 c752c55f0bb2..c4d4cd38a58f 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -2293,7 +2293,6 @@ static 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; } static void dm_init_old_md_queue(struct mapped_device *md) @@ -2304,6 +2303,7 @@ static void dm_init_old_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; blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY); } @@ -2386,6 +2386,12 @@ 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(1); if (!md->disk) @@ -2849,7 +2855,6 @@ int dm_setup_md_queue(struct mapped_device *md) break; case DM_TYPE_BIO_BASED: dm_init_old_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). |