jffs2_sync_fs makes the assumption that if CONFIG_JFFS2_FS_WRITEBUFFER
is defined then a write buffer is available and has been initialized.
However, this does is not the case when the mtd device has no
out-of-band buffer:
int jffs2_nand_flash_setup(struct jffs2_sb_info *c)
{
if (!c->mtd->oobsize)
return 0;
...
The resulting call to cancel_delayed_work_sync passing a uninitialized
(but zeroed) delayed_work struct forces lockdep to become disabled.
Signed-off-by: Daniel Santos <daniel.santos@pobox.com> Reviewed-by: Hou Tao <houtao1@huawei.com> Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>