Bug 2546450 (CVE-2026-98277) - CVE-2026-98277 kernel: eth: fbnic: ring the doorbell if a burst ends in a drop
Summary: CVE-2026-98277 kernel: eth: fbnic: ring the doorbell if a burst ends in a drop
Keywords:
Status: NEW
Alias: CVE-2026-98277
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-10-06 09:22 UTC by OSIDB Bzimport
Modified: 2026-10-10 21:27 UTC (History)
17 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:


Attachments (Terms of Use)

Description OSIDB Bzimport 2026-10-06 09:22:34 UTC
In the Linux kernel, the following vulnerability has been resolved:

eth: fbnic: ring the doorbell if a burst ends in a drop

fbnic_tx_map() skips the doorbell write, and the completion request,
for every packet handed to it with xmit_more set, counting on the
packet which ends the burst to publish them all. When that packet is
dropped instead - skb_put_padto(), skb_cow_head() or a DMA mapping
failure - nothing rings. The descriptors of the preceding packets stay
invisible to the HW until the next transmit on that queue, which for a
burst-then-idle workload may never come.

Remember the meta descriptor of the last packet left without a doorbell
and flush it from the error paths. The completion request has to be set
on that descriptor rather than simply writing the tail, otherwise the HW
would transmit the packets but never report a head, and the ring would
fill up and stall for good.

This is very similar to Joe's recent series of fixes for bnxt.
Not seen in real life, reproduced under QEMU with failure injection.


Note You need to log in before you can comment on or make changes to this bug.