github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-11-07 06:17:02 +01:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

dm-writecache: fix a crash if we attempt to use non-dax device

Browse Source 
If we specify a non-DAX device as a cache device in the 'P' mode,
dm-writecache crashes on NULL pointer dereference inside dax_synchronous.

Note that this is not a security bug because only root can trigger it.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Fixes: a466245803 ("dm writecache: reject asynchronous pmem devices")
Cc: stable@vger.kernel.org
Assisted-by: Claude:claude-opus-5
This commit is contained in:
Mikulas Patocka 2026-09-30 21:41:11 +02:00
parent c1ab80af0d
commit b15dc73f60
1 changed files with 5 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
drivers/md/dm-writecache.c
View File

@ -2499,6 +2499,11 @@ static int writecache_ctr(struct dm_target *ti, unsigned int argc, char **argv)
}
if (WC_MODE_PMEM(wc)) {
if (!wc->ssd_dev->dax_dev) {
r = -EOPNOTSUPP;
ti->error = "Cache device is not a DAX device";
goto bad;
}
if (!dax_synchronous(wc->ssd_dev->dax_dev)) {
r = -EOPNOTSUPP;
ti->error = "Asynchronous persistent memory not supported as pmem cache";