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Commit c1d0ef0e authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by Greg Kroah-Hartman
Browse files

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: 3d48b53f ("net: dev_weight: TX/RX orthogonality")
Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent dbd0f199

net/core/dev.c

+1 −1
Original line number Diff line number Diff line
@@ -5892,7 +5892,7 @@ 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;

net/core/sysctl_net_core.c

+9 −6
Original line number Diff line number Diff line
@@ -238,14 +238,17 @@ 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;

}

net/sched/sch_generic.c

+1 −1
Original line number Diff line number Diff line
@@ -403,7 +403,7 @@ static inline bool 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)) {