This is a note to let you know that I've just added the patch titled
net: Fix data-races around weight_p and dev_weight_[rt]x_bias.
to the 4.14-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-fix-data-races-around-weight_p-and-dev_weight_-r.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 835e887a1aedf1d60430bf1e5c64fa82ace01c54
Author: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
Date: Tue Aug 23 10:46:45 2022 -0700
net: Fix data-races around weight_p and dev_weight_[rt]x_bias.
[ Upstream commit bf955b5ab8f6f7b0632cdef8e36b14e4f6e77829 ]
While reading weight_p, it can be changed concurrently. Thus, we need
to add READ_ONCE() to its reader.
Also, dev_[rt]x_weight can be read/written at the same time. So, we
need to use READ_ONCE() and WRITE_ONCE() for its access. Moreover, to
use the same weight_p while changing dev_[rt]x_weight, we add a mutex
in proc_do_dev_weight().
Fixes: 3d48b53fb2ae ("net: dev_weight: TX/RX orthogonality")
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/core/dev.c b/net/core/dev.c
index ea09e0809c122..51721fb2e30cf 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5186,7 +5186,7 @@ static int process_backlog(struct napi_struct *napi, int quota)
net_rps_action_and_irq_enable(sd);
}
- napi->weight = dev_rx_weight;
+ napi->weight = READ_ONCE(dev_rx_weight);
while (again) {
struct sk_buff *skb;
diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index ac1a32d5cad3c..1b5749f2ef9c0 100644
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c
@@ -229,14 +229,17 @@ static int set_default_qdisc(struct ctl_table *table, int write,
static int proc_do_dev_weight(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
- int ret;
+ static DEFINE_MUTEX(dev_weight_mutex);
+ int ret, weight;
+ mutex_lock(&dev_weight_mutex);
ret = proc_dointvec(table, write, buffer, lenp, ppos);
- if (ret != 0)
- return ret;
-
- dev_rx_weight = weight_p * dev_weight_rx_bias;
- dev_tx_weight = weight_p * dev_weight_tx_bias;
+ if (!ret && write) {
+ weight = READ_ONCE(weight_p);
+ WRITE_ONCE(dev_rx_weight, weight * dev_weight_rx_bias);
+ WRITE_ONCE(dev_tx_weight, weight * dev_weight_tx_bias);
+ }
+ mutex_unlock(&dev_weight_mutex);
return ret;
}
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 82752dcbf2a2c..4a76ceeca6fdd 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -251,7 +251,7 @@ static inline int qdisc_restart(struct Qdisc *q, int *packets)
void __qdisc_run(struct Qdisc *q)
{
- int quota = dev_tx_weight;
+ int quota = READ_ONCE(dev_tx_weight);
int packets;
while (qdisc_restart(q, &packets)) {
