Bug 2513363 (CVE-2026-68129) - CVE-2026-68129 kernel: gve: fix Rx queue stall on alloc failure
Summary: CVE-2026-68129 kernel: gve: fix Rx queue stall on alloc failure
Keywords:
Status: NEW
Alias: CVE-2026-68129
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-08-10 12:33 UTC by OSIDB Bzimport
Modified: 2026-08-12 18:58 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
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Description OSIDB Bzimport 2026-08-10 12:33:14 UTC
In the Linux kernel, the following vulnerability has been resolved:

gve: fix Rx queue stall on alloc failure

When the system is under extreme memory pressure, page allocations can
fail during the Rx buffer refill loop. If the number of buffers posted
to hardware falls below a critical low threshold and the refill loop
exits due to allocation failures, the queue can stall:

1. The device drops incoming packets because there are no descriptors.
2. Since no packets are processed, no Rx completions are generated.
3. Because no completions occur, NAPI is never scheduled, preventing
   the refill loop from running again even after memory is freed.

This results in a permanent queue stall.

Resolve this by introducing a starvation recovery timer for each Rx queue.
If the number of buffers posted to hardware falls below a critical low
threshold, start a timer to periodically reschedule NAPI. Once NAPI runs
and successfully refills the queue above the threshold, the timer is
not rescheduled.

The threshold is set to 32 because a single maximum-sized Receive Segment
Coalescing (RSC) packet can consume up to 19 descriptors in the Rx path.
Lower thresholds (such as 8 or 16) would be insufficient to process a
complete maximum-sized RSC packet, risking packet drops or unexpected
hardware behavior under memory pressure. Setting the threshold to 32
guarantees a safe margin to handle at least one full RSC packet.


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