CVE-2025-71135

In the Linux kernel, the following vulnerability has been resolved:

md/raid5: fix possible null-pointer dereferences in raid5_store_group_thread_cnt()

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 raid5_quiesce():

raid5_quiesce(mddev, true);
raid5_quiesce(mddev, false);

since mddev->private is assigned to conf again in raid5_quiesce(), and conf
is dereferenced in several places, for example:

conf->quiesce = 0;
wake_up(&conf->wait_for_quiescent);

To fix this issue, the function should unlock mddev and return before
invoking raid5_quiesce() when conf is NULL, following the existing pattern
in raid5_change_consistency_policy().

• https://git.kernel.org/stable/c/20597b7229aea8b5bc45cd92097640257c7fc33b

  416baaa9-dc9f-4396-8d5f-8c081fb06d67
• https://git.kernel.org/stable/c/7ad6ef91d8745d04aff9cce7bdbc6320d8e05fe9

  416baaa9-dc9f-4396-8d5f-8c081fb06d67
• https://git.kernel.org/stable/c/e5abb6af905de6b2fead8a0b3f32ab0b81468a01

  416baaa9-dc9f-4396-8d5f-8c081fb06d67