CVE-2026-98654
CVE-2026-98654CVE-2026-98654
Description
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)
Scoring
| Last modified | 2026-10-18 |