While allocating packet-split buffer pages, a failed DMA mapping would
leave DMA_MAPPING_ERROR in the ps_page->dma field.
This would have two consequences:
* The next attempt to allocate that buffer would write DMA_MAPPING_ERROR
to h/w if all pages are allocated. If the h/w uses that buffer and is
handling a frame large enough to touch the affected page, it would
cause a DMA fault and be dropped. The driver would then call
dma_unmap_page() on DMA_MAPPING_ERROR and unknowingly send the
uninitialized page up the stack as part of the frame payload.
* On ring teardown, dma_unmap_page() would be called on
DMA_MAPPING_ERROR.
This condition is only reachable when MTU > 1500 and PAGE_SIZE <= 16K.
Fix this by setting ps_page->dma = 0 upon mapping failure and separately
testing ->page and ->dma during allocation and teardown.
The rewrite of the ps_pages section of e1000_clean_rx_ring was necessary
to recognize the case of an allocated page without a valid DMA mapping.
It also fixes a separate bug which would potentially leak pages on ring
teardown. The cleaner stops cleaning pages when h/w reported that it did
not write to a page in the sequence, leaving the following pages
allocated and mapped. The teardown would then break early and leak the
unused mapped pages. If the ring is re-constructed by down/up with
similar configuration, it would reclaim those lost pages. This would
only affect configurations with rx_ps_pages >= 2 (MTU > PAGE_SIZE) and
the same condition of MTU > 1500 and PAGE_SIZE <= 16K.
Signed-off-by: Matt Vollrath <redacted>
Assisted-by: Claude:claude-5-fable
Fixes: bc7f75fa9788 ("[E1000E]: New pci-express e1000 driver (currently for ICH9 devices only)")
Cc: stable@vger.kernel.org
---
v2:
* Reword last paragraph of description.
---
drivers/net/ethernet/intel/e1000e/netdev.c | 19 ++++++++++++-------
1 file changed, 12 insertions(+), 7 deletions(-)
diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ ethernet/intel/e1000e/netdev.c
index 26f45ee8c7e7..063fc8cd2673 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -759,12 +759,15 @@ static void e1000_alloc_rx_buffers_ps(struct e1000_ring *rx_ring,
adapter->alloc_rx_buff_failed++;
goto no_buffers;
}
+ }
+ if (!ps_page->dma) {
ps_page->dma = dma_map_page(&pdev->dev,
ps_page->page,
0, PAGE_SIZE,
DMA_FROM_DEVICE);
if (dma_mapping_error(&pdev->dev,
ps_page->dma)) {
+ ps_page->dma = 0;
dev_err(&adapter->pdev->dev,
"Rx DMA page map failed\n");
adapter->rx_dma_failed++;@@ -1722,13 +1725,15 @@ static void e1000_clean_rx_ring(struct e1000_ring *rx_ring)
for (j = 0; j < PS_PAGE_BUFFERS; j++) {
ps_page = &buffer_info->ps_pages[j];
- if (!ps_page->page)
- break;
- dma_unmap_page(&pdev->dev, ps_page->dma, PAGE_SIZE,
- DMA_FROM_DEVICE);
- ps_page->dma = 0;
- put_page(ps_page->page);
- ps_page->page = NULL;
+ if (ps_page->dma) {
+ dma_unmap_page(&pdev->dev, ps_page->dma,
+ PAGE_SIZE, DMA_FROM_DEVICE);
+ ps_page->dma = 0;
+ }
+ if (ps_page->page) {
+ put_page(ps_page->page);
+ ps_page->page = NULL;
+ }
}
}