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: Denys Fedoryshchenko <denys@visp.net.lb>
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 98c0084..7d7070b 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -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 @@
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 @@
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 @@
if (handle == 0)
goto err_out3;
}
+ lockdep_set_class(qdisc_lock(sch), &qdisc_tx_lock);
}
sch->handle = handle;
