kernel/linux
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ synced 2026-09-28 19:20:30 +00:00
Code Issues Releases Packages Activity

s390/dcssblk: fix kernel crash with list_add corruption

Browse source 
commit c8f40a0bcc upstream.

Commit fb08a1908c ("dax: simplify the dax_device <-> gendisk
association") introduced new logic for gendisk association, requiring
drivers to explicitly call dax_add_host() and dax_remove_host().

For dcssblk driver, some dax_remove_host() calls were missing, e.g. in
device remove path. The commit also broke error handling for out_dax case
in device add path, resulting in an extra put_device() w/o the previous
get_device() in that case.

This lead to stale xarray entries after device add / remove cycles. In the
case when a previously used struct gendisk pointer (xarray index) would be
used again, because blk_alloc_disk() happened to return such a pointer, the
xa_insert() in dax_add_host() would fail and go to out_dax, doing the extra
put_device() in the error path. In combination with an already flawed error
handling in dcssblk (device_register() cleanup), which needs to be
addressed in a separate patch, this resulted in a missing device_del() /
klist_del(), and eventually in the kernel crash with list_add corruption on
a subsequent device_add() / klist_add().

Fix this by adding the missing dax_remove_host() calls, and also move the
put_device() in the error path to restore the previous logic.

Fixes: fb08a1908c ("dax: simplify the dax_device <-> gendisk association")
Cc: <stable@vger.kernel.org> # 5.17+
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Gerald Schaefer 2023-08-10 10:22:36 +02:00 • committed by Greg Kroah-Hartman
commit 6489ec0107
1 changed files with 3 additions and 1 deletions
Download patch file Download diff file Expand all files Collapse all files