In the Linux kernel, the following vulnerability has been resolved: md/raid5: fix possible null-pointer dereferences in raid5storegroupthreadcnt() The variable mddev->private is first assigned to conf and then checked: conf = mddev->private; if (!conf) ... If conf is NULL, then mddev->private is also NULL. In this case, null-pointer dereferences can occur when calling raid5quiesce(): raid5quiesce(mddev, true); raid5quiesce(mddev, false); since mddev->private is assigned to conf again in raid5quiesce(), and conf is dereferenced in several places, for example: conf->quiesce = 0; wakeup(&conf->waitforquiescent); To fix this issue, the function should unlock mddev and return before invoking raid5quiesce() when conf is NULL, following the existing pattern in raid5changeconsistency_policy().