CVE-2026-43466

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

net/mlx5e: Fix DMA FIFO desync on error CQE SQ recovery

In case of a TX error CQE, a recovery flow is triggered, mlx5eresettxqsqccpc() resets dmafifocc to 0 but not dmafifopc, desyncing the DMA FIFO producer and consumer.

After recovery, the producer pushes new DMA entries at the old dmafifopc, while the consumer reads from position 0. This causes us to unmap stale DMA addresses from before the recovery.

The DMA FIFO is a purely software construct with no HW counterpart. At the point of reset, all WQEs have been flushed so dmafifocc is already equal to dmafifopc. There is no need to reset either counter, similar to how skb_fifo pc/cc are untouched.

Remove the 'dmafifocc = 0' reset.

This fixes the following WARNING: WARNING: CPU: 0 PID: 0 at drivers/iommu/dma-iommu.c:1240 iommudmaunmappage+0x79/0x90 Modules linked in: mlx5vdpa vringh vdpa bonding mlx5ib mlx5vfiopci ipip mlx5fwctl tunnel4 mlx5core ibipoib geneve ip6gre ipgre gre nftables ip6tunnel rdmaucm ibuverbs ibumad vfiopci vfiopcicore actmirred actskbedit actvlan vhostnet vhost tap ip6tablemangle ip6tablenat ip6tablefilter ip6tables iptablemangle clsmatchall nfnetlinkcttimeout actgact clsflower schingress vhostiotlb iptableraw tunnel6 vfioiommutype1 vfio openvswitch nsh rpcsecgsskrb5 authrpcgss oidregistry xtconntrack xtMASQUERADE nfconntracknetlink nfnetlink iptablenat nfnat xtaddrtype brnetfilter overlay zram zsmalloc rpcrdma ibiser libiscsi scsitransportiscsi rdmacm iwcm ibcm ibcore fuse [last unloaded: nftables] CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.13.0-rc5forupstreammindebug202412302133 #1 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 RIP: 0010:iommudmaunmappage+0x79/0x90 Code: 2b 4d 3b 21 72 26 4d 3b 61 08 73 20 49 89 d8 44 89 f9 5b 4c 89 f2 4c 89 e6 48 89 ef 5d 41 5c 41 5d 41 5e 41 5f e9 c7 ae 9e ff <0f> 0b 5b 5d 41 5c 41 5d 41 5e 41 5f c3 66 2e 0f 1f 84 00 00 00 00 Call Trace: <IRQ> ? __warn+0x7d/0x110 ? iommudmaunmap_page+0x79/0x90 ? reportbug+0x16d/0x180 ? handlebug+0x4f/0x90 ? excinvalidop+0x14/0x70 ? asmexcinvalidop+0x16/0x20 ? iommudmaunmappage+0x79/0x90 ? iommudmaunmappage+0x2e/0x90 dmaunmappageattrs+0x10d/0x1b0 mlx5etxwidmaunmap+0xbe/0x120 [mlx5core] mlx5epolltxcq+0x16d/0x690 [mlx5core] mlx5enapipoll+0x8b/0xac0 [mlx5core] _napipoll+0x24/0x190 netrxaction+0x32a/0x3b0 ? mlx5eqcompint+0x7e/0x270 [mlx5core] ? notifiercallchain+0x35/0xa0 handlesoftirqs+0xc9/0x270 irqexitrcu+0x71/0xd0 commoninterrupt+0x7f/0xa0 </IRQ> <TASK> asmcommoninterrupt+0x22/0x40