pkt_sched: Add lockdep annotation for qdisc locks (25bfcd5a) · Commits · 戴 / test

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:

Denys Fedoryshchenko <denys@visp.net.lb> Signed-off-by:

Jarek Poplawski <jarkao2@gmail.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

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;

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