This is a note to let you know that I've just added the patch titled
net/mlx5e: kTLS, Fix incorrect page refcounting
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-mlx5e-ktls-fix-incorrect-page-refcounting.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit fdc154e5f624e1f848e5721d406269f32fed109a
Author: Dragos Tatulea <dtatulea@xxxxxxxxxx>
Date: Thu Nov 7 20:35:24 2024 +0200
net/mlx5e: kTLS, Fix incorrect page refcounting
[ Upstream commit dd6e972cc5890d91d6749bb48e3912721c4e4b25 ]
The kTLS tx handling code is using a mix of get_page() and
page_ref_inc() APIs to increment the page reference. But on the release
path (mlx5e_ktls_tx_handle_resync_dump_comp()), only put_page() is used.
This is an issue when using pages from large folios: the get_page()
references are stored on the folio page while the page_ref_inc()
references are stored directly in the given page. On release the folio
page will be dereferenced too many times.
This was found while doing kTLS testing with sendfile() + ZC when the
served file was read from NFS on a kernel with NFS large folios support
(commit 49b29a573da8 ("nfs: add support for large folios")).
Fixes: 84d1bb2b139e ("net/mlx5e: kTLS, Limit DUMP wqe size")
Signed-off-by: Dragos Tatulea <dtatulea@xxxxxxxxxx>
Signed-off-by: Tariq Toukan <tariqt@xxxxxxxxxx>
Link: https://patch.msgid.link/20241107183527.676877-5-tariqt@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ktls_tx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ktls_tx.c
index 52a56622034a0..807ed5963a496 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ktls_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_accel/ktls_tx.c
@@ -233,7 +233,7 @@ tx_sync_info_get(struct mlx5e_ktls_offload_context_tx *priv_tx,
while (remaining > 0) {
skb_frag_t *frag = &record->frags[i];
- get_page(skb_frag_page(frag));
+ page_ref_inc(skb_frag_page(frag));
remaining -= skb_frag_size(frag);
info->frags[i++] = *frag;
}
@@ -321,7 +321,7 @@ void mlx5e_ktls_tx_handle_resync_dump_comp(struct mlx5e_txqsq *sq,
stats = sq->stats;
mlx5e_tx_dma_unmap(sq->pdev, dma);
- put_page(wi->resync_dump_frag_page);
+ page_ref_dec(wi->resync_dump_frag_page);
stats->tls_dump_packets++;
stats->tls_dump_bytes += wi->num_bytes;
}
@@ -412,12 +412,12 @@ mlx5e_ktls_tx_handle_ooo(struct mlx5e_ktls_offload_context_tx *priv_tx,
err_out:
for (; i < info.nr_frags; i++)
- /* The put_page() here undoes the page ref obtained in tx_sync_info_get().
+ /* The page_ref_dec() here undoes the page ref obtained in tx_sync_info_get().
* Page refs obtained for the DUMP WQEs above (by page_ref_add) will be
* released only upon their completions (or in mlx5e_free_txqsq_descs,
* if channel closes).
*/
- put_page(skb_frag_page(&info.frags[i]));
+ page_ref_dec(skb_frag_page(&info.frags[i]));
return MLX5E_KTLS_SYNC_FAIL;
}
