UBUNTU-CVE-2026-74453: Medium severity ubuntu/linux-azure vulnerability
In the Linux kernel, the following vulnerability has been resolved: drm/vc4: Zero the tile state data array before each BIN job The binner BO is a single 16MB buffer split into 512KB slots that are handed out to jobs at submission time and recycled as jobs complete, without ever being cleared. Each slot holds the job's Tile State Data Array (TSDA) at its start, followed by the tile allocation pool. While the tile allocation pool is only walked by the render thread through branches the binner generated during the current job, the TSDA is the PTB's own per-tile bookkeeping and is consumed by the hardware itself. Although the kernel sets the "Auto-initialise Tile State Data Array" flag in the tile binning mode configuration, the PTB demonstrably still acts on stale tile state left by the slot's previous user: the binner ends up creating invalid command streams with invalid primitive streams and branches, which can cause GPU hangs as observed in [1][2]. Zero the TSDA when the job's binning slot is configured. This clears 48 bytes per tile (~24KB for a 1080p frame) in the submission path, and guarantees the PTB never sees another job's tile state. The tile count is only checked for being non-zero today, so the 8-bit fields it comes from can describe a tile state array almost six times larger than the slot it has to live in. Bound it before the slot is handed out, since such size decides how much of the slot is left for the tile alloc pool.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
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ubuntu/linux-aws-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1117.124~20.04.1 - Upgrade
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ubuntu/linux-azure-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1123.132~20.04.1 - Upgrade
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ubuntu/linux-azure-fde-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1122.131~20.04.1 - Upgrade
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ubuntu/linux-gcp-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1118.128~20.04.1 - Upgrade
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ubuntu/linux-hwe-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-198.208~20.04.1 - Upgrade
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ubuntu/linux-ibm-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1111.115~20.04.1 - Upgrade
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ubuntu/linux-intel-iotg-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1112.118~20.04.1 - Upgrade
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ubuntu/linux-lowlatency-hwe-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-195.205~20.04.1 - Upgrade
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ubuntu/linux-oracle-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1114.120~20.04.1 - Upgrade
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ubuntu/linux-riscv-5.15to a version that resolves this vulnerability.Fixed in 5.15.0-1111.115~20.04.1 - Upgrade
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ubuntu/linuxto a version that resolves this vulnerability.Fixed in 5.15.0-198.208 - Upgrade
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ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 5.15.0-1117.124 - Upgrade
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ubuntu/linux-azureto a version that resolves this vulnerability.Fixed in 5.15.0-1123.132 - Upgrade
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ubuntu/linux-azure-fdeto a version that resolves this vulnerability.Fixed in 5.15.0-1122.131 - Upgrade
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ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 5.15.0-1118.128 - Upgrade
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ubuntu/linux-gketo a version that resolves this vulnerability.Fixed in 5.15.0-1113.119 - Upgrade
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ubuntu/linux-gkeopto a version that resolves this vulnerability.Fixed in 5.15.0-1100.108 - Upgrade
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ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 5.15.0-1111.115 - Upgrade
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ubuntu/linux-intel-iotgto a version that resolves this vulnerability.Fixed in 5.15.0-1112.118 - Upgrade
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ubuntu/linux-kvmto a version that resolves this vulnerability.Fixed in 5.15.0-1109.114 - Upgrade
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ubuntu/linux-lowlatencyto a version that resolves this vulnerability.Fixed in 5.15.0-195.205 - Upgrade
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ubuntu/linux-nvidiato a version that resolves this vulnerability.Fixed in 5.15.0-1112.113 - Upgrade
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ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 5.15.0-1114.120 - Upgrade
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ubuntu/linux-xilinx-zynqmpto a version that resolves this vulnerability.Fixed in 5.15.0-1080.84 - Upgrade
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ubuntu/linux-bluefieldto a version that resolves this vulnerability.Fixed in 5.15.0-1101.103 - Upgrade
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ubuntu/linux-intel-iot-realtimeto a version that resolves this vulnerability.Fixed in 5.15.0-1109.111 - Upgrade
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ubuntu/linux-realtimeto a version that resolves this vulnerability.Fixed in 5.15.0-1116.125 - Upgrade
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ubuntu/linux-aws-fipsto a version that resolves this vulnerability.Fixed in 5.15.0-1117.124+fips1 - Upgrade
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ubuntu/linux-azure-fipsto a version that resolves this vulnerability.Fixed in 5.15.0-1123.132+fips1 - Upgrade
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ubuntu/linux-fipsto a version that resolves this vulnerability.Fixed in 5.15.0-198.208+fips1 - Upgrade
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ubuntu/linux-gcp-fipsto a version that resolves this vulnerability.Fixed in 5.15.0-1118.128+fips1 - Upgrade
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ubuntu/linux-nvidia-tegrato a version that resolves this vulnerability.Fixed in 6.8.0-1036.39 - Configuration
Zero the TSDA when the job's binning slot is configured, before the slot is handed out to the job.
Linux kernel drm/vc4 Tile State Data Array (TSDA) initialization = zeroed
Event History
Frequently Asked Questions
What level of access does an attacker need?
The supplied CVSS vector indicates local access with low privileges is required. No user interaction is required.
Which Ubuntu kernel packages are in scope?
The affected software list includes ubuntu/linux, ubuntu/linux-azure, ubuntu/linux-azure-fips, ubuntu/linux-aws-fips, ubuntu/linux-fips, ubuntu/linux-gcp, ubuntu/linux-gcp-fips, and ubuntu/linux-oracle. No affected or fixed version numbers are provided.
How might this issue appear operationally?
The described failure mode is invalid GPU command, primitive, and branch streams that can result in GPU hangs. This symptom alone does not establish that this vulnerability is the cause.
What does the available fix do?
The resolution clears the Tile State Data Array when a binning slot is configured, preventing the hardware from consuming tile state left by a previous job.