Re: [PATCH net] net: openvswitch: fix data race in ovs_vport_get_upcall_stats
From: Eric Dumazet <edumazet@google.com>
Date: 2026-01-19 18:30:30
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Subsystem:
networking [general], openvswitch, the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Aaron Conole, Eelco Chaudron, Ilya Maximets, Linus Torvalds
On Mon, Jan 19, 2026 at 7:14 PM David Yang [off-list ref] wrote:
quoted hunk ↗ jump to hunk
In ovs_vport_get_upcall_stats(), some statistics protected by u64_stats_sync, are read and accumulated in ignorance of possible u64_stats_fetch_retry() events. These statistics are already accumulated by u64_stats_inc(). Fix this by reading them into temporary variables first. Fixes: 1933ea365aa7 ("net: openvswitch: Add support to count upcall packets") Signed-off-by: David Yang <mmyangfl@gmail.com> --- net/openvswitch/vport.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)diff --git a/net/openvswitch/vport.c b/net/openvswitch/vport.c index 6bbbc16ab778..bc46d661b527 100644 --- a/net/openvswitch/vport.c +++ b/net/openvswitch/vport.c@@ -319,13 +319,17 @@ int ovs_vport_get_upcall_stats(struct vport *vport, struct sk_buff *skb) for_each_possible_cpu(i) { const struct vport_upcall_stats_percpu *stats; unsigned int start; + __u64 n_success; + __u64 n_fail;
Please use u64 New __u64 only makes sense in include/uapi/ Feel free to change existing variables for consistency in your V2 patch (please wait ~24 hours before sending it)
diff --git a/net/openvswitch/vport.c b/net/openvswitch/vport.c
index 6bbbc16ab7780840c0f0d18f629b4747efe8f0e4..1c51f1fe0810976bbeece229be4370cad9a31c1c100644
--- a/net/openvswitch/vport.c
+++ b/net/openvswitch/vport.c@@ -310,12 +310,10 @@ void ovs_vport_get_stats(struct vport *vport,struct ovs_vport_stats *stats)
*/
int ovs_vport_get_upcall_stats(struct vport *vport, struct sk_buff *skb)
{
+ u64 tx_success = 0, tx_fail = 0;
struct nlattr *nla;
int i;
- __u64 tx_success = 0;
- __u64 tx_fail = 0;
-
for_each_possible_cpu(i) {
const struct vport_upcall_stats_percpu *stats;
unsigned int start;