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Commit 25bfcd5a authored by Jarek Poplawski's avatar Jarek Poplawski Committed by David S. Miller
Browse files

pkt_sched: Add lockdep annotation for qdisc locks 



Qdisc locks are initialized in the same function, qdisc_alloc(), so
lockdep can't distinguish tx qdisc lock from rx and reports "possible
recursive locking detected" when both these locks are taken eg. while
using act_mirred with ifb. This looks like a false positive. Anyway,
after this patch these locks will be reported more exactly.

Reported-by: default avatarDenys Fedoryshchenko <denys@visp.net.lb>
Signed-off-by: default avatarJarek Poplawski <jarkao2@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 8608db03

net/sched/sch_api.c

+7 −0
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ 
#include <linux/kmod.h>

#include <linux/list.h>

#include <linux/hrtimer.h>

#include <linux/lockdep.h>



#include <net/net_namespace.h>

#include <net/sock.h>
@@ -707,6 +708,10 @@ static int qdisc_graft(struct net_device *dev, struct Qdisc *parent, 
	return err;

}



/* lockdep annotation is needed for ingress; egress gets it only for name */

static struct lock_class_key qdisc_tx_lock;

static struct lock_class_key qdisc_rx_lock;



/*

   Allocate and initialize new qdisc.
@@ -767,6 +772,7 @@ qdisc_create(struct net_device *dev, struct netdev_queue *dev_queue, 
	if (handle == TC_H_INGRESS) {

		sch->flags |= TCQ_F_INGRESS;

		handle = TC_H_MAKE(TC_H_INGRESS, 0);

		lockdep_set_class(qdisc_lock(sch), &qdisc_rx_lock);

	} else {

		if (handle == 0) {

			handle = qdisc_alloc_handle(dev);
@@ -774,6 +780,7 @@ qdisc_create(struct net_device *dev, struct netdev_queue *dev_queue, 
			if (handle == 0)

				goto err_out3;

		}

		lockdep_set_class(qdisc_lock(sch), &qdisc_tx_lock);

	}



	sch->handle = handle;