drm/i915/gt: fix refcount underflow in intel_engine_park_heartbeat
In the Linux kernel, the following vulnerability has been resolved: drm/i915/gt: fix refcount underflow in intel_engine_park_heartbeat A use-after-free / refcount underflow is possible when the heartbeat worker and intel_engine_park_heartbeat() race to release the same engine->heartbeat.systole request. The heartbeat worker reads engine->heartbeat.systole and calls i915_request_put() on it when the request is complete, but clears the pointer in a separate, non-atomic step. Concurrently, a request retirement on another CPU can drop the engine wakeref to zero, triggering __engine_park() -> intel_engine_park_heartbeat(). If the heartbeat timer is pending at that point, cancel_delayed_work() returns true and intel_engine_park_heartbeat() reads the stale non-NULL systole pointer and calls i915_request_put() on it again, causing a refcount underflow: ``` <4> [487.221889] Workqueue: i915-unordered engine_retire [i915] <4> [487.222640] RIP: 0010:refcount_warn_saturate+0x68/0xb0 ... <4> [487.222707] Call Trace: <4> [487.222711] <4> [487.222716] intel_engine_park_heartbeat.part.0+0x6f/0x80 [i915] <4> [487.223115] intel_engine_park_heartbeat+0x25/0x40 [i915] <4> [487.223566] __engine_park+0xb9/0x650 [i915] <4> [487.223973] ____intel_wakeref_put_last+0x2e/0xb0 [i915] <4> [487.224408] __intel_wakeref_put_last+0x72/0x90 [i915] <4> [487.224797] intel_context_exit_engine+0x7c/0x80 [i915] <4> [487.225238] intel_context_exit+0xf1/0x1b0 [i915] <4> [487.225695] i915_request_retire.part.0+0x1b9/0
CVE-2026-31656
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2026-31656
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "058179e72e0956a2dfe4927db6cbe5fbfb2406aa",
"lessThan": "82034799c6c14b3104668878c3f3e5786f777126",
"versionType": "git"
},
{
"status": "affected",
"version": "058179e72e0956a2dfe4927db6cbe5fbfb2406aa",
"lessThan": "70d3e622b10092fc483e28e57b4e8c49d9cc7f68",
"versionType": "git"
},
{
"status": "affected",
"version": "058179e72e0956a2dfe4927db6cbe5fbfb2406aa",
"lessThan": "8ce44d28a84fd5e053a88b04872a89d95c0779d4",
"versionType": "git"
},
{
"status": "affected",
"version": "058179e72e0956a2dfe4927db6cbe5fbfb2406aa",
"lessThan": "ca3f48c3567dd49efdc55b80029ae74659c682ee",
"versionType": "git"
},
{
"status": "affected",
"version": "058179e72e0956a2dfe4927db6cbe5fbfb2406aa",
"lessThan": "a00e92bf6583d019a4fb2c2df7007e6c9b269ce7",
"versionType": "git"
},
{
"status": "affected",
"version": "058179e72e0956a2dfe4927db6cbe5fbfb2406aa",
"lessThan": "2af8b200cae3fdd0e917ecc2753b28bb40c876c1",
"versionType": "git"
},
{
"status": "affected",
"version": "058179e72e0956a2dfe4927db6cbe5fbfb2406aa",
"lessThan": "455d98ed527fc94eed90406f90ab2391464ca657",
"versionType": "git"
},
{
"status": "affected",
"version": "058179e72e0956a2dfe4927db6cbe5fbfb2406aa",
"lessThan": "4c71fd099513bfa8acab529b626e1f0097b76061",
"versionType": "git"
}
],
"programFiles": [
"drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "5.5"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "5.5",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "5.10.258",
"versionType": "semver",
"lessThanOrEqual": "5.10.*"
},
{
"status": "unaffected",
"version": "5.15.203",
"versionType": "semver",
"lessThanOrEqual": "5.15.*"
},
{
"status": "unaffected",
"version": "6.1.169",
"versionType": "semver",
"lessThanOrEqual": "6.1.*"
},
{
"status": "unaffected",
"version": "6.6.135",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.82",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.23",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "6.19.13",
"versionType": "semver",
"lessThanOrEqual": "6.19.*"
},
{
"status": "unaffected",
"version": "7.0",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"drivers/gpu/drm/i915/gt/intel_engine_heartbeat.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-31656
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #39938 · Revision 1
- Added to Heist Feed
- Publisher date