CVE-2026-98654drm/amd/display: Atomize IRQ register read/modify/write ops

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Atomize IRQ register read/modify/write ops [Why] The OTG_GLOBAL_SYNC_STATUS register controls various HW IRQ sources for the output timing generator (OTG). VUPDATE_NO_LOCK is one of them. To enable the IRQ, driver sets the VUPDATE_NO_LOCK_EN bit in the GLOBAL_SYNC_STATUS register. To ack the IRQ after it fires, the driver sets the VUPDATE_NO_LOCK_CLEAR bit in the same GLOBAL_SYNC_STATUS register. The bit sets are done through read/modify/write operations, which are not atomic. Thus, the following race is possible: Thread A: IRQ handler: *HW IRQ fires* # IRQ disable val = read(GLOBAL_SYNC_STATUS) unset(val, VUPDATE_NO_LOCK_EN) write(val, GLOBAL_SYNC_STATUS) # ACK reads VUPDATE_NO_LOCK_EN unset val1 = read(GLOBAL_SYNC_STATUS) set(val1, VUPDATE_NO_LOCK_CLEAR) # IRQ enable val = read(GLOBAL_SYNC_STATUS) set(val, VUPDATE_NO_LOCK_EN) write(val, GLOBAL_SYNC_STATUS) # BAD! clears VUPDATE_NO_LOCK_EN write(val1, GLOBAL_SYNC_STATUS) Regarding the tagged Fixes: change, it appears the change made this race more likely to occur. Since VUPDATE_NO_LOCK is now the sole IRQ source for vblank handling, a single race on high refresh panels can lead to a time out. [How] The GLOBAL_SYNC_STATUS register is only one example, other IRQ control registers also share the same scheme. On top of GLOBAL_SYNC_STATUS, let's clean up those as well. To keep things simple, Let's atomize the IRQ rmw ops via a single driver-wide spinlock. Due to the small scope of this lock, it is unlikely to cause noticeable overhead on top of all the existing locking within the IRQ set/handle paths. Since DM is responsible for locking, wrap dc_interrupt_set/ack with the spinlock in the new amdgpu_dm_irq_set/ack functions. Migrate/drop all references in DM to dc_interrupt_set/ack to use amdgpu_dm_irq_set/ack instead. (cherry picked from commit 70de0a0216583a53c946155f8c8adedfdca6b4e7)

CVSS

Not yet scored

Weakness (CWE)

Not given

Known exploited

Not in CISA's KEV catalog

EPSS (exploitation in the next 30 days)

Not loaded for this CVE

Assigned by

Linux

NVD analysis

Received

Record last updated

Oct 18, 2026

First seen by InfoSec Signals

Oct 18, 2026

The CVE record on cve.org · NVD's entry

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