CVE-2026-98919
CVE-2026-98919CVE-2026-98919
Description
In the Linux kernel, the following vulnerability has been resolved:
drm/xe: harden adjust_idledly() against divide-by-zero and overflow
adjust_idledly() has several corner-case issues flagged during review:
1. If xe_gt_clock_init() failed to recognise the crystal clock,
gt->info.timestamp_base is 0, which makes idledly_units_ps also 0.
The subsequent DIV_ROUND_CLOSEST(..., idledly_units_ps) is then a
divide-by-zero and panics the kernel.
2. The tick-to-ns conversions are done in u32:
idledly * idledly_units_ps, (maxcnt - 1) * 1000
Both overflow u32 before DIV_ROUND_CLOSEST() sees them.
3. If IDLE_WAIT_TIME reads back as 0, maxcnt evaluates to 0 and
the maxcnt - 1 clamp wraps to 0xFFFFFFFF in u32.
4. The register only stores whole ticks, so the clamped ns value has
to be converted to ticks and back. DIV_ROUND_CLOSEST() can round
that conversion up past maxcnt:
maxcnt = 640 ns, one tick = 666664 ps
clamp: max
Scoring
| Last modified | 2026-10-23 |