In the Linux kernel, the following vulnerability has been resolved:

ibmvnic: Do not reset dql stats on NON_FATAL err

All ibmvnic resets, make a call to netdev_tx_reset_queue() when
re-opening the device. netdev_tx_reset_queue() resets the num_queued
and num_completed byte counters. These stats are used in Byte Queue
Limit (BQL) algorithms. The difference between these two stats tracks
the number of bytes currently sitting on the physical NIC. ibmvnic
increases the number of queued bytes though calls to
netdev_tx_sent_queue() in the drivers xmit function. When, VIOS reports
that it is done transmitting bytes, the ibmvnic device increases the
number of completed bytes through calls to netdev_tx_completed_queue().
It is important to note that the driver batches its transmit calls and
num_queued is increased every time that an skb is added to the next
batch, not necessarily when the batch is sent to VIOS for transmission.

Unlike other reset types, a NON FATAL reset will not flush the sub crq
tx buffers. Therefore, it is possible for the batched skb array to be
partially full. So if there is call to netdev_tx_reset_queue() when
re-opening the device, the value of num_queued (0) would not account
for the skb's that are currently batched. Eventually, when the batch
is sent to VIOS, the call to netdev_tx_completed_queue() would increase
num_completed to a value greater than the num_queued. This causes a
BUG_ON crash:

ibmvnic 30000002: Firmware reports error, cause: adapter problem.
Starting recovery...
ibmvnic 30000002: tx error 600
ibmvnic 30000002: tx error 600
ibmvnic 30000002: tx error 600
ibmvnic 30000002: tx error 600
------------[ cut here ]------------
kernel BUG at lib/dynamic_queue_limits.c:27!
Oops: Exception in kernel mode, sig: 5
[....]
NIP dql_completed+0x28/0x1c0
LR ibmvnic_complete_tx.isra.0+0x23c/0x420 [ibmvnic]
Call Trace:
ibmvnic_complete_tx.isra.0+0x3f8/0x420 [ibmvnic] (unreliable)
ibmvnic_interrupt_tx+0x40/0x70 [ibmvnic]
__handle_irq_event_percpu+0x98/0x270
---[ end trace ]---

Therefore, do not reset the dql stats when performing a NON_FATAL reset.
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Wed, 01 Oct 2025 12:00:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: ibmvnic: Do not reset dql stats on NON_FATAL err All ibmvnic resets, make a call to netdev_tx_reset_queue() when re-opening the device. netdev_tx_reset_queue() resets the num_queued and num_completed byte counters. These stats are used in Byte Queue Limit (BQL) algorithms. The difference between these two stats tracks the number of bytes currently sitting on the physical NIC. ibmvnic increases the number of queued bytes though calls to netdev_tx_sent_queue() in the drivers xmit function. When, VIOS reports that it is done transmitting bytes, the ibmvnic device increases the number of completed bytes through calls to netdev_tx_completed_queue(). It is important to note that the driver batches its transmit calls and num_queued is increased every time that an skb is added to the next batch, not necessarily when the batch is sent to VIOS for transmission. Unlike other reset types, a NON FATAL reset will not flush the sub crq tx buffers. Therefore, it is possible for the batched skb array to be partially full. So if there is call to netdev_tx_reset_queue() when re-opening the device, the value of num_queued (0) would not account for the skb's that are currently batched. Eventually, when the batch is sent to VIOS, the call to netdev_tx_completed_queue() would increase num_completed to a value greater than the num_queued. This causes a BUG_ON crash: ibmvnic 30000002: Firmware reports error, cause: adapter problem. Starting recovery... ibmvnic 30000002: tx error 600 ibmvnic 30000002: tx error 600 ibmvnic 30000002: tx error 600 ibmvnic 30000002: tx error 600 ------------[ cut here ]------------ kernel BUG at lib/dynamic_queue_limits.c:27! Oops: Exception in kernel mode, sig: 5 [....] NIP dql_completed+0x28/0x1c0 LR ibmvnic_complete_tx.isra.0+0x23c/0x420 [ibmvnic] Call Trace: ibmvnic_complete_tx.isra.0+0x3f8/0x420 [ibmvnic] (unreliable) ibmvnic_interrupt_tx+0x40/0x70 [ibmvnic] __handle_irq_event_percpu+0x98/0x270 ---[ end trace ]--- Therefore, do not reset the dql stats when performing a NON_FATAL reset.
Title ibmvnic: Do not reset dql stats on NON_FATAL err
References

cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2025-10-01T11:42:34.308Z

Reserved: 2025-10-01T11:39:39.400Z

Link: CVE-2023-53463

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2025-10-01T12:15:48.120

Modified: 2025-10-01T12:15:48.120

Link: CVE-2023-53463

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.