lkml.org 
[lkml]   [2021]   [Feb]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 4.14 31/57] xen/netback: avoid race in xenvif_rx_ring_slots_available()
Date
From: Juergen Gross <jgross@suse.com>

[ Upstream commit ec7d8e7dd3a59528e305a18e93f1cb98f7faf83b ]

Since commit 23025393dbeb3b8b3 ("xen/netback: use lateeoi irq binding")
xenvif_rx_ring_slots_available() is no longer called only from the rx
queue kernel thread, so it needs to access the rx queue with the
associated queue held.

Reported-by: Igor Druzhinin <igor.druzhinin@citrix.com>
Fixes: 23025393dbeb3b8b3 ("xen/netback: use lateeoi irq binding")
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Wei Liu <wl@xen.org>
Link: https://lore.kernel.org/r/20210202070938.7863-1-jgross@suse.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/xen-netback/rx.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/net/xen-netback/rx.c b/drivers/net/xen-netback/rx.c
index f152246c7dfb7..ddfb1cfa2dd94 100644
--- a/drivers/net/xen-netback/rx.c
+++ b/drivers/net/xen-netback/rx.c
@@ -38,10 +38,15 @@ static bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue)
RING_IDX prod, cons;
struct sk_buff *skb;
int needed;
+ unsigned long flags;
+
+ spin_lock_irqsave(&queue->rx_queue.lock, flags);

skb = skb_peek(&queue->rx_queue);
- if (!skb)
+ if (!skb) {
+ spin_unlock_irqrestore(&queue->rx_queue.lock, flags);
return false;
+ }

needed = DIV_ROUND_UP(skb->len, XEN_PAGE_SIZE);
if (skb_is_gso(skb))
@@ -49,6 +54,8 @@ static bool xenvif_rx_ring_slots_available(struct xenvif_queue *queue)
if (skb->sw_hash)
needed++;

+ spin_unlock_irqrestore(&queue->rx_queue.lock, flags);
+
do {
prod = queue->rx.sring->req_prod;
cons = queue->rx.req_cons;
--
2.27.0


\
 
 \ /
  Last update: 2021-02-22 14:25    [W:0.164 / U:3.032 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site