Description (CNA)
In the Linux kernel, the following vulnerability has been resolved: ice: Restore Ordered MMIO Writes for Tx Doorbells The DQL accounting state which tracks the number of bytes queued for the NIC to transmit, namely dql->num_queued, is updated by the ICE driver when it invokes __netdev_tx_sent_queue(). Subsequently the driver updates the hardware queue tail allowing the NIC to begin processing the work queue. The queue accounting update should be ordered before the NIC begins transmitting descriptors. The transmit path currently updates the hardware doorbell using writel_relaxed(), which (on arm64) does not provide the same ordering guarantees between writes to normal memory and writes to MMIO registers that writel() does. This introduces a potential race where the NIC begins transmitting descriptors before the dql->num_queued update is globally visible. If the NIC finishes before the update is observed by dql_completed(), it detects an invalid state where more bytes have been completed than have been queued. When this happens the following BUG_ON is triggered. BUG_ON(count > num_queued - dql->num_completed); This has been observed and manifests as the following crash (note that the trace has been trimmed) in an environment with sustained network load that uses an Intel Corporation Ethernet Controller E810-XXV for SFP (rev 02) on an arm64 machine. Replacing writel_relaxed() with writel() in a test kernel eliminated the crash in the user's workload, which previously reproduced the issue reliably. kernel BUG at lib/dynamic_queue_limits.c:99 Internal error: Oops - BUG: 00000000f2000800 [#1] SMP pc : dql_completed+0x268/0x2a0 lr : ice_clean_tx_irq+0x1d4/0x620 [ice] Call trace: dql_completed+0x268/0x2a0 (P) ice_napi_poll+0x94/0x520 [ice] __napi_poll+0x48/0x3f0 net_rx_action+0x194/0x420 This restores the behaviour prior to commit ccde82e90946 ("ice: add E830 Earliest TxTime First Offload support"), which changed the notification mechanism from writel() to writel_relaxed().
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| Linux / Linux | affected ccde82e909467abdf098a8ee6f63e1ecf9a47ce5 before b7725acf9c574debb97ae1613569ac9e148438be; affected ccde82e909467abdf098a8ee6f63e1ecf9a47ce5 before f94ab1fffd009250d72c6dc1662cb84467ac5365; affected ccde82e909467abdf098a8ee6f63e1ecf9a47ce5 before 7a579dec8423bba7bec96fcfcb2e30838b0858ee |
| Linux / Linux | affected 6.18; unaffected 0 before 6.18; unaffected 6.18.57 through 6.18.*; unaffected 7.2.11 through 7.2.*; unaffected 7.3 through * |
CWE
No CWE identifiers supplied.