This is a note to let you know that I've just added the patch titled
dm: fix potential for q->make_request_fn NULL pointer
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
dm-fix-potential-for-q-make_request_fn-null-pointer.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 47ace7e012b9f7ad71d43ac9063d335ea3d6820b Mon Sep 17 00:00:00 2001
From: Mike Snitzer <snitzer@xxxxxxxxxx>
Date: Mon, 27 Jan 2020 14:07:23 -0500
Subject: dm: fix potential for q->make_request_fn NULL pointer
From: Mike Snitzer <snitzer@xxxxxxxxxx>
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@xxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxx
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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);
Patches currently in stable-queue which might be from snitzer@xxxxxxxxxx are
queue-4.19/dm-crypt-fix-benbi-iv-constructor-crash-if-used-in-authenticated-mode.patch
queue-4.19/dm-fix-potential-for-q-make_request_fn-null-pointer.patch
queue-4.19/dm-zoned-support-zone-sizes-smaller-than-128mib.patch
queue-4.19/dm-space-map-common-fix-to-ensure-new-block-isn-t-already-in-use.patch
