{"id":"CVE-2026-98965","title":"ice: Restore Ordered MMIO Writes for Tx Doorbells","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nice: Restore Ordered MMIO Writes for Tx Doorbells\n\nThe DQL accounting state which tracks the number of bytes queued for the\nNIC to transmit, namely dql->num_queued, is …","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= ccde82e909467abdf098a8ee6f63e1ecf9a47ce5 < b7725acf9c574debb97ae1613569ac9e148438be","Linux >= ccde82e909467abdf098a8ee6f63e1ecf9a47ce5 < f94ab1fffd009250d72c6dc1662cb84467ac5365","Linux >= ccde82e909467abdf098a8ee6f63e1ecf9a47ce5 < 7a579dec8423bba7bec96fcfcb2e30838b0858ee","Linux 6.18"],"published":"2026-10-23","updated":"2026-10-23","sourceUpdated":"2026-10-23T12:19:34.754Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-98965","references":[{"url":"https://git.kernel.org/stable/c/b7725acf9c574debb97ae1613569ac9e148438be"},{"url":"https://git.kernel.org/stable/c/f94ab1fffd009250d72c6dc1662cb84467ac5365"},{"url":"https://git.kernel.org/stable/c/7a579dec8423bba7bec96fcfcb2e30838b0858ee"}],"tags":["cve.org"],"ingestedAt":"2026-10-23T13:24:55.554Z","slug":"CVE-2026-98965","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nice: Restore Ordered MMIO Writes for Tx Doorbells\n\nThe DQL accounting state which tracks the number of bytes queued for the\nNIC to transmit, namely dql->num_queued, is updated by the ICE driver\nwhen it invokes __netdev_tx_sent_queue(). Subsequently the driver\nupdates the hardware queue tail allowing the NIC to begin processing the\nwork queue. The queue accounting update should be ordered before the NIC\nbegins transmitting descriptors.\n\nThe transmit path currently updates the hardware doorbell using\nwritel_relaxed(), which (on arm64) does not provide the same ordering\nguarantees between writes to normal memory and writes to MMIO registers\nthat writel() does. This introduces a potential race where the NIC\nbegins transmitting descriptors before the dql->num_queued update is\nglobally visible. If the NIC finishes before the update is observed by\ndql_completed(), it detects an invalid state where more bytes have been\ncompleted than have been queued. When this happens the following BUG_ON\nis triggered.\n\n  BUG_ON(count > num_queued - dql->num_completed);\n\nThis has been observed and manifests as the following crash (note that\nthe trace has been trimmed) in an environment with sustained network\nload that uses an Intel Corporation Ethernet Controller E810-XXV for SFP\n(rev 02) on an arm64 machine. Replacing writel_relaxed() with writel()\nin a test kernel eliminated the crash in the user's workload, which\npreviously reproduced the issue reliably.\n\n  kernel BUG at lib/dynamic_queue_limits.c:99\n\nInternal error: Oops - BUG: 00000000f2000800 [#1] SMP\npc : dql_completed+0x268/0x2a0\nlr : ice_clean_tx_irq+0x1d4/0x620 [ice]\nCall trace:\ndql_completed+0x268/0x2a0 (P)\nice_napi_poll+0x94/0x520 [ice]\n__napi_poll+0x48/0x3f0\nnet_rx_action+0x194/0x420\n\nThis restores the behaviour prior to commit ccde82e90946 (\"ice: add E830\nEarliest TxTime First Offload support\"), which changed the notification\nmechanism from writel() to writel_relaxed().\n\n## Affected\n\n- `Linux >= ccde82e909467abdf098a8ee6f63e1ecf9a47ce5 < b7725acf9c574debb97ae1613569ac9e148438be`\n- `Linux >= ccde82e909467abdf098a8ee6f63e1ecf9a47ce5 < f94ab1fffd009250d72c6dc1662cb84467ac5365`\n- `Linux >= ccde82e909467abdf098a8ee6f63e1ecf9a47ce5 < 7a579dec8423bba7bec96fcfcb2e30838b0858ee`\n- `Linux 6.18`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}