News
Abstract
DLPAR remove of a network SR-IOV device operation might result in error messages on the console.
Content
Linux Releases Affected
RedHat Enterprise Linux 8.x, for Power LE
RedHat Enterprise Linux 9.x, for Power LE
SUSE Linux Enterprise Server 15
RedHat Enterprise Linux 9.x, for Power LE
SUSE Linux Enterprise Server 15
IBM Systems Affected
Linux logical partitions that run on any PowerVM-based POWER9 or Power10 system.
Symptoms
Network drivers use the page_pool interface to manage DMA mappings. When the DLPAR remove of a network SR-IOV adapter operation is initiated, the Page Pool interface asynchronously unmaps the DMA-mapped pages for the device.
In such a scenario, then the following messages are displayed on the console:
[ 1134.086999] __iommu_free+0x1e0/0x1f0 (unreliable)
[ 1134.087005] iommu_unmap_page+0x6c/0xb0
[ 1134.087010] dma_iommu_unmap_page+0x24/0x40
[ 1134.087013] dma_unmap_page_attrs+0x1a8/0x240
[ 1134.087019] page_pool_return_page+0x58/0x190
[ 1134.087024] page_pool_release+0x108/0x2c0
[ 1134.087028] page_pool_release_retry+0x2c/0x110
[ 1134.087032] process_one_work+0x294/0x580
[ 1134.087037] worker_thread+0xa8/0x5e0
[ 1134.087041] kthread+0x124/0x130
[ 1134.087044] ret_from_kernel_thread+0x5c/0x64
Workaround
To perform the DLPAR remove of a SR-IOV device operation, complete the following steps:
- Set the SR-IOV link to down by running the following command:
ip link set down dev <sriov-interface> - Wait for approximately 5 minutes. Waiting gives enough time for all the buffers that are mapped to the SR-IOV device to be flushed out.
- Initiate the DLPAR remove of a SR-IOV device operation.
Fix Outlook
IBM is working to include a fix in a future release.
I/O device impacted
None
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Document Information
Modified date:
04 June 2025
UID
ibm17235374