CVE-2025-38621

BUG: kernel NULL pointer dereference, address: 00000000000000e0 ... Oops: Oops: 0000 [#1] SMP NOPTI CPU: 2 UID: 0 PID: 85 Comm: kworker/2:1 Not tainted 6.16.0+ #94 PREEMPT(none) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014 Workqueue: mdmisc mdstartsync RIP: 0010:rdevaddable+0x4d/0xf0 ... Call Trace: <TASK> mdstartsync+0x329/0x480 processonework+0x226/0x6d0 workerthread+0x19e/0x340 kthread+0x10f/0x250 retfromfork+0x14d/0x180 retfromforkasm+0x1a/0x30 </TASK> Modules linked in: raid10 CR2: 00000000000000e0 ---[ end trace 0000000000000000 ]--- RIP: 0010:rdev_addable+0x4d/0xf0

mdsparesneedchange in mdstartsync will call rdevaddable which protected by rcureadlock/rcureadunlock. This rcu context will help protect rdev won't be released, but rdev->mddev will be set to NULL before we call synchronizercu in mdkickrdevfromarray. Fix this by using READONCE and check does rdev->mddev still alive.

References

Affected packages

Debian:13 / linux

Package

Name: linux
Purl: pkg:deb/debian/linux?arch=source

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Affected versions

6.*

6.12.38-1

6.12.41-1

6.12.43-1

6.13~rc6-1~exp1

6.13~rc7-1~exp1

6.13.2-1~exp1

6.13.3-1~exp1

6.13.4-1~exp1

6.13.5-1~exp1

6.13.6-1~exp1

6.13.7-1~exp1

6.13.8-1~exp1

6.13.9-1~exp1

6.13.10-1~exp1

6.13.11-1~exp1

6.14.3-1~exp1

6.14.5-1~exp1

6.14.6-1~exp1

6.15~rc7-1~exp1

6.15-1~exp1

6.15.1-1~exp1

6.15.2-1~exp1

6.15.3-1~exp1

6.15.4-1~exp1

6.15.5-1~exp1

6.15.6-1~exp1

6.16~rc7-1~exp1

6.16-1~exp1

6.16.1-1~exp1

6.16.3-1

Ecosystem specific

{
    "urgency": "not yet assigned"
}

Debian:14 / linux