iommu/mediatek: Fix NULL pointer dereference when printing dev_name

published 2025-02-26 20 mo ago modified 2026-06-17 4 mo ago also EUVD-2022-54805

cvss: 5.5; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 19%
public exploits: 0; none known

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

When larbdev is NULL (in the case I hit, the node is incorrectly set iommus = <&iommu NUM>), it will cause device_link_add() fail and kernel crashes when we try to print dev_name(larbdev).

Let's fail the probe if a larbdev is NULL to avoid invalid inputs from dts.

It should work for normal correct setting and avoid the crash caused by my incorrect setting.

Error log: [ 18.189042][ T301] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000050 ... [ 18.344519][ T301] pstate: a0400005 (NzCv daif +PAN -UAO) [ 18.345213][ T301] pc : mtk_iommu_probe_device+0xf8/0x118 [mtk_iommu] [ 18.346050][ T301] lr : mtk_iommu_probe_device+0xd0/0x118 [mtk_iommu] [ 18.346884][ T301] sp : ffffffc00a5635e0 [ 18.347392][ T301] x29: ffffffc00a5635e0 x28: ffffffd44a46c1d8 [ 18.348156][ T301] x27: ffffff80c39a8000 x26: ffffffd44a80cc38 [ 18.348917][ T301] x25: 0000000000000000 x24: ffffffd44a80cc38 [ 18.349677][ T301] x23: ffffffd44e4da4c6 x22: ffffffd44a80cc38 [ 18.350438][ T301] x21: ffffff80cecd1880 x20: 0000000000000000 [ 18.351198][ T301] x19: ffffff80c439f010 x18: ffffffc00a50d0c0 [ 18.351959][ T301] x17: ffffffffffffffff x16: 0000000000000004 [ 18.352719][ T301] x15: 0000000000000004 x14: ffffffd44eb5d420 [ 18.353480][ T301] x13: 0000000000000ad2 x12: 0000000000000003 [ 18.354241][ T301] x11: 00000000fffffad2 x10: c0000000fffffad2 [ 18.355003][ T301] x9 : a0d288d8d7142d00 x8 : a0d288d8d7142d00 [ 18.355763][ T301] x7 : ffffffd44c2bc640 x6 : 0000000000000000 [ 18.356524][ T301] x5 : 0000000000000080 x4 : 0000000000000001 [ 18.357284][ T301] x3 : 0000000000000000 x2 : 0000000000000005 [ 18.358045][ T301] x1 : 0000000000000000 x0 : 0000000000000000 [ 18.360208][ T301] Hardware name: MT6873 (DT) [ 18.360771][ T301] Call trace: [ 18.361168][ T301] dump_backtrace+0xf8/0x1f0 [ 18.361737][ T301] dump_stack_lvl+0xa8/0x11c [ 18.362305][ T301] dump_stack+0x1c/0x2c [ 18.362816][ T301] mrdump_common_die+0x184/0x40c [mrdump] [ 18.363575][ T301] ipanic_die+0x24/0x38 [mrdump] [ 18.364230][ T301] atomic_notifier_call_chain+0x128/0x2b8 [ 18.364937][ T301] die+0x16c/0x568 [ 18.365394][ T301] __do_kernel_fault+0x1e8/0x214 [ 18.365402][ T301] do_page_fault+0xb8/0x678 [ 18.366934][ T301] do_translation_fault+0x48/0x64 [ 18.368645][ T301] do_mem_abort+0x68/0x148 [ 18.368652][ T301] el1_abort+0x40/0x64 [ 18.368660][ T301] el1h_64_sync_handler+0x54/0x88 [ 18.368668][ T301] el1h_64_sync+0x68/0x6c [ 18.368673][ T301] mtk_iommu_probe_device+0xf8/0x118 [mtk_iommu] ...

Patch / fix

fixed in 1 distros 3 links 4

Linux Linux 5.15.46, 5.17, 5.17.14, 5.18.3, 5.19

debian ubuntu suse

linux Debian 14, Debian 13, Debian 12 5.18.5-1

debian advisories DEBIAN-CVE-2022-49424

linux Ubuntu 22.04 LTS 5.15.0-47.51
linux-aws Ubuntu 22.04 LTS 5.15.0-1019.23
linux-gcp Ubuntu 22.04 LTS 5.15.0-1017.23
linux-gke Ubuntu 22.04 LTS 5.15.0-1015.18
linux-ibm Ubuntu 22.04 LTS 5.15.0-1013.15
linux-kvm Ubuntu 22.04 LTS 5.15.0-1017.21
linux-azure Ubuntu 22.04 LTS 5.15.0-1019.24
linux-gkeop Ubuntu 22.04 LTS 5.15.0-1002.4

ubuntu advisories UBUNTU-CVE-2022-49424

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

kernel-64kb SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS, SLE High Performance Computing 15 SP5-ESPOS 5.14.21-150500.55.100.1
kernel-syms SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS +1 more 5.14.21-150500.55.100.1
kernel-source SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE Micro 5.5 +2 more 5.14.21-150500.55.100.1
kernel-default SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE Micro 5.5 +3 more 5.14.21-150500.55.100.1
kernel-obs-build SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS +1 more 5.14.21-150500.55.100.1
kernel-default-base SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE Micro 5.5 +2 more 5.14.21-150500.55.100.1.150500.6.47.1
kernel-rt SLE Micro 5.4, SLE Micro 5.3 5.14.21-150400.15.115.1
kernel-source-rt SLE Micro 5.4, SLE Micro 5.3 5.14.21-150400.15.115.1

suse advisories SUSE-SU-2025:1241-1 SUSE-SU-2025:1183-1 SUSE-SU-2025:1176-1 SUSE-SU-2025:1027-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2022-49424 updated 2026-11-06

kernel: iommu/mediatek: Fix NULL pointer dereference when printing dev_name

Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat Enterprise Linux 10 kernel
not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.27% chance of exploitation in the next 30 days, higher than 19% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
NVD	3.1	5.5	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

Linux Linux

Classification

Weakness

CWE-476 NULL Pointer Dereference

Technology feeds

Linux kernel rss critical rss

References

Sources

CVE List CVE-2022-49424
NVD CVE-2022-49424

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary