[PATCH 5.11 098/122] ch_ktls: Fix kernel panic

Greg Kroah-Hartman
2021-04-19T13:15:44Z

From: Vinay Kumar Yadav <vinay.yadav@chelsio.com>

commit 1a73e427b824133940c2dd95ebe26b6dce1cbf10 upstream.

Taking page refcount is not ideal and causes kernel panic
sometimes. It's better to take tx_ctx lock for the complete
skb transmit, to avoid page cleanup if ACK received in middle.

Fixes: 5a4b9fe7fece ("cxgb4/chcr: complete record tx handling")
Signed-off-by: Vinay Kumar Yadav <vinay.yadav@chelsio.com>
Signed-off-by: Rohit Maheshwari <rohitm@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/chelsio/inline_crypto/ch_ktls/chcr_ktls.c | 24 ++--------
1 file changed, 5 insertions(+), 19 deletions(-)

--- a/drivers/net/ethernet/chelsio/inline_crypto/ch_ktls/chcr_ktls.c
+++ b/drivers/net/ethernet/chelsio/inline_crypto/ch_ktls/chcr_ktls.c
@@ -2015,12 +2015,11 @@ static int chcr_ktls_xmit(struct sk_buff
* we will send the complete record again.
*/

+ spin_lock_irqsave(&tx_ctx->base.lock, flags);
+
do {
- int i;

cxgb4_reclaim_completed_tx(adap, &q->q, true);
- /* lock taken */
- spin_lock_irqsave(&tx_ctx->base.lock, flags);
/* fetch the tls record */
record = tls_get_record(&tx_ctx->base, tcp_seq,
&tx_info->record_no);
@@ -2079,11 +2078,11 @@ static int chcr_ktls_xmit(struct sk_buff
tls_end_offset, skb_offset,
0);

- spin_unlock_irqrestore(&tx_ctx->base.lock, flags);
if (ret) {
/* free the refcount taken earlier */
if (tls_end_offset < data_len)
dev_kfree_skb_any(skb);
+ spin_unlock_irqrestore(&tx_ctx->base.lock, flags);
goto out;
}

@@ -2093,16 +2092,6 @@ static int chcr_ktls_xmit(struct sk_buff
continue;
}

- /* increase page reference count of the record, so that there
- * won't be any chance of page free in middle if in case stack
- * receives ACK and try to delete the record.
- */
- for (i = 0; i < record->num_frags; i++)
- __skb_frag_ref(&record->frags[i]);
- /* lock cleared */
- spin_unlock_irqrestore(&tx_ctx->base.lock, flags);
-
-
/* if a tls record is finishing in this SKB */
if (tls_end_offset <= data_len) {
ret = chcr_end_part_handler(tx_info, skb, record,
@@ -2127,13 +2116,9 @@ static int chcr_ktls_xmit(struct sk_buff
data_len = 0;
}

- /* clear the frag ref count which increased locally before */
- for (i = 0; i < record->num_frags; i++) {
- /* clear the frag ref count */
- __skb_frag_unref(&record->frags[i]);
- }
/* if any failure, come out from the loop. */
if (ret) {
+ spin_unlock_irqrestore(&tx_ctx->base.lock, flags);
if (th->fin)
dev_kfree_skb_any(skb);

@@ -2148,6 +2133,7 @@ static int chcr_ktls_xmit(struct sk_buff

} while (data_len > 0);

+ spin_unlock_irqrestore(&tx_ctx->base.lock, flags);
atomic64_inc(&port_stats->ktls_tx_encrypted_packets);
atomic64_add(skb_data_len, &port_stats->ktls_tx_encrypted_bytes);